Files
Open_Ultra_SAST/src/openultrasast/cpg/backend.py
T
Marius CiepluchandClaude Opus 4.8 0fef399869 fix(scan): the portioner asks single attempts and reads coverage, not wall time
End-to-end, the adaptive portioner regressed completion -- 64 of 406 against 7.7 hard-cap 153 --
while finding the same defects. The cause: the portioner timed each portion with run_batch, which
splits on failure internally, so one portion folded its own eight-way retry into its number and read
953 s. The sizer fitted a per-visit rate from that and collapsed its budget to 14 visits, spending
the back half of the deadline on tiny portions.

Two portioning layers were fighting. The portioner is now the sole retry layer: it asks
run_batch_once, a single invocation whose kill returns the answers it streamed, so its wall time is
the cost of one attempt. And it observes COVERAGE, not emptiness -- a portion that came back short
of the ids it asked halves the budget, because it was too big for the ceiling; only a whole answer
gives a clean per-visit sample to fit from.

run_batch_once is new on CpgResult, wired on the disposable and sharded paths; a backend without it
falls back to run_batch unchanged. Host controls cover the single-attempt path and the
halve-on-short-answer rule.

1,424 tests pass, nineteen skipped. The end-to-end plugin re-measure on a frozen tree is the open
item; the mechanism (a kill keeps what finished) and the sizer logic are unit-verified.

Co-Authored-By: Claude Opus 4.8 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo
2026-09-22 23:00:14 +02:00

1743 lines
90 KiB
Python

"""The Joern subprocess seam — the single place this codebase touches a CPG engine (Req 4.1, 4.4, 4.5).
Joern is JVM/Scala. Everything crosses one subprocess boundary: ``joern-parse`` builds a ``cpg.bin`` from a
source tree, then ``joern --script`` runs a CPGQL script that prints a JSON payload. Nothing is imported
in-process, so the core install keeps ``dependencies = []`` and an absent engine costs a recorded reason
rather than a traceback.
Two rules hold everywhere below:
* **Fail closed.** A build or query that errors, times out, or prints something unparseable yields *no*
verdict. The model layer then reports ``suspicion``. A wrong verdict is worse than no verdict — that is the
whole reason this arbiter exists.
* **Fence the payload.** Joern prints a banner, compilation notices and a REPL prompt on stdout. The script
brackets its JSON between markers so parsing can never swallow the noise around it.
We do not build a control-flow or dataflow engine here (Req 4.4): the CFG, PDG and call graph our flat IR
lacks are exactly what is being adopted.
"""
from __future__ import annotations
import json
import logging
import os
import re
import shutil
import signal
import stat
import subprocess
import tempfile
import time
from collections.abc import Callable, Mapping, Sequence
from dataclasses import dataclass, field, replace
from pathlib import Path
from typing import Any, Protocol
from ..model.contracts import ExecutionBudget
from .artifact import GraphArtifact, GraphCensus, GraphIdentity
from .session import EngineSession
logger = logging.getLogger(__name__)
QUERIES_DIR = Path(__file__).resolve().parent / "queries"
# The payload fence. Joern's stdout carries a banner and a prompt; the script prints these around its JSON.
BEGIN = "---OUSAST-CPG-BEGIN---"
END = "---OUSAST-CPG-END---"
BUILD_TIMEOUT_SECONDS = 900 # a large tree takes minutes; the go/no-go records what it actually cost
# A slice's questions answer in seconds; a repository's do not. Measured on a 637-file WordPress plugin:
# 13 dominance requests answer in 50s (most of it loading the graph) and 2,500 taint requests exceed 300s.
# The constant was chosen when a "scan" meant an excerpt, and a repository scan is not a slower slice -- it
# is a different order of question, so the ceiling is configurable rather than a number to keep raising.
QUERY_TIMEOUT_SECONDS = 300
# How many parts a failed batch is retried in. Small enough that a response the engine could not
# serialize becomes several it can, large enough that recovery is not one invocation per request.
_BATCH_SPLITS = 8
QUERY_TIMEOUT_ENV = "OPENULTRASAST_CPG_QUERY_TIMEOUT"
# A JVM with no -Xmx takes a quarter of physical RAM for its heap. On a contributor's laptop that is the
# difference between a scan running in the background and a scan the machine notices, and it made the
# first repository measurements unreproducible: runs were killed under memory pressure at different
# points, so the numbers described the host, not the engine. Bound it, and let the operator raise it.
CPG_HEAP_MB = 2048
# Explicit opt-in for the transaction-owned engine session (M2). Unset means the disposable path.
SESSION_ENV = "OUSAST_ENGINE_SESSION"
HEAP_ENV = "OPENULTRASAST_CPG_HEAP_MB"
# `joern-parse` detects the language and then shells out to a frontend, and on a large tree it can fail where
# the frontend alone succeeds -- measured on a 637-file WordPress plugin, where joern-parse threw after
# applying overlays while `php2cpg` on the same tree produced a 4.3MB CPG with no errors. Joern's own message
# recommends the direct route for large codebases, so this is the documented fallback rather than a
# workaround. The names are Joern's frontend executables.
_FRONTENDS = {
"php": "php2cpg",
"python": "pysrc2cpg",
"javascript": "jssrc2cpg",
"typescript": "jssrc2cpg",
"java": "javasrc2cpg",
"c": "c2cpg",
"c_cpp": "c2cpg",
}
# Languages where the frontend is run DIRECTLY instead of through `joern-parse`, and how many times.
#
# `joern-parse` invokes the same frontend, but measured on one WordPress slice it succeeds far less often
# and, worse, tells you nothing when it does not: thirteen lines of output, exit status 0, "Successfully
# wrote graph", and a graph with no methods in it. The frontend logs a warning per file it drops.
#
# joern-parse 5 of 8 builds usable
# php2cpg 11 of 12 builds usable, and names the files it dropped
#
# php2cpg 4.0.623 fails intermittently when it reads its PHP parser's output: the parser's bytes are
# complete and valid -- verified by capturing them -- so the defect is inside the frontend's own JSON
# reading, and nothing outside it can repair a given attempt. What CAN be done is notice (the warning is
# right there) and try again. Compacting the parser's output to a fifth of its size, running the parser
# through a shim, and pinning `ForkJoinPool.common.parallelism=1` were each tried and each changed nothing.
_PREFER_FRONTEND = frozenset({"php"})
# The extensions that count as source for a language, used to ask whether a graph is missing anything.
_LANGUAGE_EXTENSIONS: dict[str, tuple[str, ...]] = {"php": (".php",)}
# The script a frontend drives THROUGH the interpreter, relative to the frontend binary's directory. The
# interpreter has to be able to read it as much as the repository: php2cpg 4.0.625 in an install the
# containerised `php` had no mount for parsed 1 of 637 files -- "Could not open input file" 64 times,
# exit 0 -- and read for a minute as a frontend regression.
_FRONTEND_PARSER: dict[str, str] = {"php": "frontends/php2cpg/bin/php-parser/php-parser.php"}
# A source file above this size is a data table, not code: WP Statistics carries two vendored browser
# profile files of 1.6 MB and 1.5 MB, each one array literal, and they were 60% of the graph (9.6 MB with
# them, 3.6 MB without). The reaching-definitions overlay does not merely slow down on them, it never
# finishes -- 25 minutes at 4 GB, OutOfMemoryError inside `initGen` at every cap `--max-num-def` offers,
# because a single assignment of a hundred-thousand-element literal is ONE definition. Nothing flows
# through a lookup table that a scan could name, and the file is named in the log so the exclusion is
# visible rather than silent. Task 5.13.
MAX_SOURCE_BYTES = 1_000_000
# The overlay a graph must carry for `reachableByFlows` to be answered from the saved graph rather than
# recomputed at every load; Joern names it so in `cpg.metaData.overlays`.
DATAFLOW_OVERLAY = "dataflowOss"
# Frontends that shell out to a separate interpreter, and the command that proves it can read a file.
# `php2cpg` drives PHP-Parser through whatever `php` is on PATH, so the frontend is only as good as that
# interpreter's view of the filesystem -- and a `php` that cannot see the tree does not fail, it produces an
# empty graph with exit status 0 and no warnings.
_INTERPRETERS: dict[str, str] = {"php": "php"}
# A `global` declaration inside a CLOSURE makes php2cpg 4.0.623 emit a node with two AST parents, and Joern
# then refuses to apply its own dataflow overlay to the graph:
#
# java.lang.AssertionError: Iterable was expected to have exactly one element, but it has 2.
# Hint: trying to resolve astParent ... (which is probably a malformed cpg)
#
# Four lines reproduce it, and the whole graph is lost -- not the file, the GRAPH, so every query over the
# repository fails at load:
#
# <?php
# function f($n) {
# h("p", function($p) { global $g; return $p . $g; });
# }
#
# Controlled: `use` is irrelevant (it asserts with and without), and a `global` at function scope is fine.
# Bisected from a 637-file plugin down to one file, one function, this construct.
#
# It is rare enough to exclude rather than to give up over: 1 of 637 files in Paid Memberships Pro, 1 of 357
# in WP Statistics, 0 of 169 in MW WP Form -- about 0.2%. Excluding them costs those files and saves the
# other 99.8%, which is the difference between a scan and no scan at all. They are reported as `unparsed`,
# so the coverage section names them rather than implying they were clean.
_CLOSURE = re.compile(r"\bfunction\s*\(")
# The release that fixes the miscompile (joernio/joern#6281, same root cause as #6269, fixed by #6270).
# At or above it the exclusion below is a loss with nothing to buy, so it is not applied.
CLOSURE_DEFECT_FIXED_IN = (4, 0, 625)
_JOERN_JAR = re.compile(r"^io\.joern\.joern-cli-(\d+)\.(\d+)\.(\d+)\.jar$")
def joern_version() -> tuple[int, int, int] | None:
"""The installed Joern's version, read off the jar beside the launcher; ``None`` when it cannot be told.
The launcher is a shell script with no `--version`, and every release ships `lib/io.joern.joern-cli-X.Y.Z.jar`
next to it. Unknown is unknown: a caller gating a workaround on this keeps the workaround.
"""
launcher = shutil.which("joern")
if launcher is None:
return None
lib = Path(launcher).resolve().parent / "lib"
try:
names = [entry.name for entry in lib.iterdir()]
except OSError:
return None
for name in names:
match = _JOERN_JAR.match(name)
if match:
return (int(match.group(1)), int(match.group(2)), int(match.group(3)))
return None
_GLOBAL_IN_BODY = re.compile(r"\bglobal\s+\$")
FRONTEND_BUILD_ATTEMPTS = 4
# Request fields that describe the REPOSITORY rather than the region, and are therefore identical in every
# request of a batch. They are hoisted to a single `--param` instead of being repeated thousands of times.
#
# Not a micro-optimisation. `hookCallbacks` is 16,270 characters on a 637-file plugin, and repeating it
# across 2,500 requests made a 42.5MB request file of which 41.7MB was the same string over and over. Joern
# parsed that with ujson inside a 2GB heap and the whole batch died in ForkJoinPool, which the driver
# correctly reported as `query_failed` for all 2,500 regions -- a whole-repository scan that decided nothing.
_SHARED_REQUEST_FIELDS = ("hookCallbacks", "dispatchApply")
Runner = Callable[..., subprocess.CompletedProcess[str]]
# A streamed answer: one JSON document per line inside the fence, each carrying the request id it answers,
# printed and flushed as the engine finishes it. The point is what a KILL keeps. A batch that used to build
# its whole answer and print it once lost every answer when it was killed at the ceiling -- 116 requests at
# 300 s, then eight fresh JVM starts to ask them again. Streamed, the same kill keeps everything that had
# finished, and only the unfinished requests are asked again.
STREAM_ID = "id"
STREAM_ROWS = "rows"
PARTIAL = "__partial__"
def extract_payload(stdout: str) -> object | None:
"""The JSON between the fence markers, or ``None`` when it is absent or malformed.
Two shapes are accepted. The committed one is a single document. The streamed one is a document per
line, each `{"id": ..., "rows": [...]}` or `{"__census__": [...]}`, which this assembles into the same
mapping the callers already read. A streamed body whose closing fence never arrived -- the process was
killed -- still yields every complete line, marked ``__partial__`` so a caller can tell a harvest from a
whole answer. A single-document body without its closing fence is still nothing, as before: there is
no partial truth in half a document.
"""
start = stdout.find(BEGIN)
if start < 0:
return None
end = stdout.find(END, start + 1)
body = stdout[start + len(BEGIN) : end if end >= 0 else len(stdout)].strip()
streamed = _streamed(body, complete=end >= 0)
if streamed is not None:
return streamed
if end < 0:
return None
# Joern logs to STDOUT, and it does so while the script is running -- so a log line can land INSIDE the
# fence, ahead of the payload. `[INFO ] Attempting to determine flows from empty list of sources.` did
# exactly that and cost a 205-request batch every one of its answers, reported as `query_failed`. The
# payload is always one JSON object or array, so trim to its own brackets rather than trusting the fence
# to contain nothing else.
payload = _decoded_json(body)
if payload is None:
logger.debug("cpg query payload was not valid JSON")
return payload
def _streamed(body: str, *, complete: bool) -> dict[str, object] | None:
"""Assemble a streamed body, or ``None`` when the body is not streamed at all.
A line is streamed when it is a JSON object carrying an id or the census key. Anything else on a line
is what Joern logged and is skipped; a trailing line that does not parse is the one the kill cut
through, and it is dropped rather than guessed at.
"""
answers: dict[str, object] = {}
saw_stream = False
for line in body.splitlines():
text = line.strip()
if not text.startswith("{"):
continue
try:
document = json.loads(text)
except ValueError:
continue
if not isinstance(document, dict):
continue
# A census LINE carries nothing but the census. A legacy single document carries the census beside
# every answer, and reading that as a census line dropped every answer it sat beside.
if set(document) == {"__census__"}:
answers["__census__"] = document["__census__"]
saw_stream = True
elif STREAM_ID in document and STREAM_ROWS in document:
answers[str(document[STREAM_ID])] = document[STREAM_ROWS]
saw_stream = True
if not saw_stream:
return None
if not complete:
answers[PARTIAL] = True
return answers
def _decoded_json(body: str) -> object | None:
"""The first complete JSON document in ``body``, ignoring whatever Joern logged around it.
Trimming to the outermost brackets is the obvious approach and the wrong one: a log line is `[INFO ] ...`,
so its own bracket comes first. This starts a decode at each line that opens a document and keeps the
first that parses, which is exactly one line of work when nothing was logged.
"""
decoder = json.JSONDecoder()
offset = 0
for line in body.splitlines(keepends=True):
if line.lstrip().startswith(("{", "[")):
try:
payload, _ = decoder.raw_decode(body, offset + len(line) - len(line.lstrip()))
except ValueError:
pass
else:
decoded: object = payload
return decoded
offset += len(line)
return None
@dataclass(frozen=True)
class CpgResult:
"""A built CPG and the ways to query it. Opaque: only ``model/`` reads through these.
``run_batch`` is optional so a backend that cannot answer many questions in one invocation still fits
this shape -- the driver falls back to ``run``, once per request. But a backend that CAN batch must
attach it HERE, because this is the driver's only way to discover the capability. Leaving it off does
not fail: it silently costs a JVM per region, which is how batching sat unreachable behind a passing
test suite until a repository scan made the cost visible.
"""
cpg_path: Path
run: Callable[[str, Mapping[str, object]], object | None]
run_batch: Callable[[str, Mapping[str, Mapping[str, object]]], dict[str, list[object]] | None] | None = None
# A SINGLE batch attempt: no internal split-on-failure, so its wall time is the cost of exactly one
# invocation and a killed one returns the answers it streamed before the kill. The scan-level portioner
# uses this because it is itself the retry layer -- timing `run_batch`, which splits internally, once
# read one portion at 953 s (its own retries folded in) and collapsed the adaptive sizer.
run_batch_once: Callable[[str, Mapping[str, Mapping[str, object]]], dict[str, list[object]] | None] | None = None
# Files the frontend read and could not turn into a graph. A CPG is not all-or-nothing: `php2cpg` logs a
# warning per file it drops and still exits 0 with a graph that is missing them, so a scan over the
# remainder is a scan of LESS CODE THAN IT WAS ASKED ABOUT, and silence about those files is the same
# quiet failure as an empty query result. The names travel with the CPG so the driver can say so.
unparsed: tuple[str, ...] = ()
# Removes the scratch tree this CPG lives in. A build allocates a temp directory holding the graph, its
# request files and joern's own workspace copy; nothing reclaimed it, and a day of scanning left 1,055
# directories and 355MB behind on a disk that was already at 95%. The driver disposes in a `finally`.
cleanup: Callable[[], None] | None = None
execution_diagnostics: Callable[[], tuple[str, ...]] | None = None
class CpgBackend(Protocol):
def available(self) -> bool: ...
def build(self, root: Path) -> CpgResult | None: ...
@dataclass
class NullBackend:
"""No engine. Every verdict degrades to ``suspicion`` and the caller records ``cpg_unavailable``."""
reason: str = "cpg_unavailable"
def available(self) -> bool:
return False
def build(self, root: Path) -> CpgResult | None:
del root
return None
def engine_runtime_identity(
*,
include_tests: bool = True,
include_build_configs: bool = True,
language: str | None = None,
execution_budget: ExecutionBudget | None = None,
) -> str:
"""Installed frontend/adaptation bytes, also used by comparison eligibility provenance."""
from .artifact import digest_value, graph_bytes
budget = execution_budget
deadline = budget.deadline_monotonic if budget else float("inf")
launcher = shutil.which("joern")
version = joern_version()
installation = []
if launcher is not None and version is not None:
home = Path(launcher).resolve().parent
engine = ".".join(map(str, version))
frontends = {_FRONTENDS.get(language, "joern-parse")} if language else set(_FRONTENDS.values())
candidates = {home / f"lib/io.joern.joern-cli-{engine}.jar", Path(launcher).resolve()}
for frontend in frontends:
candidates.add(home / f"frontends/{frontend}/lib/io.joern.{frontend}-{engine}.jar")
frontend_launcher = shutil.which(frontend)
if frontend_launcher is not None:
candidates.add(Path(frontend_launcher).resolve())
if "jssrc2cpg" in frontends:
candidates.update({home / "ousast-frontend-retention-v1/manifest.json", home / "frontends/jssrc2cpg/bin/astgen/astgen-linux"})
for candidate in sorted(candidates):
installation.append((candidate.name, graph_bytes(candidate, deadline) if candidate.is_file() else "absent"))
return digest_value(
{
"version": version,
"files": installation,
"include_tests": include_tests,
"include_build_configs": include_build_configs,
"java_options": os.environ.get("JAVA_TOOL_OPTIONS", ""),
}
)
@dataclass
class JoernBackend:
"""``joern-parse`` then ``joern --script``, both out of process and both timeout-bounded."""
runner: Runner | None = None
include_tests: bool = True # Explicit input policy for the versioned frontend adaptation.
include_build_configs: bool = True # Explicit retention of supported build configuration source.
build_timeout: int = BUILD_TIMEOUT_SECONDS
query_timeout: int = field(default_factory=lambda: _configured_timeout())
heap_mb: int = 0 # 0 means read the environment, then fall back to CPG_HEAP_MB
queries_dir: Path = field(default_factory=lambda: QUERIES_DIR)
# Why the last build refused, so the driver can name it instead of reporting a bare `cpg_build_failed`.
last_failure: str = ""
execution_budget: ExecutionBudget | None = None
# M2 11.3: opt-in transport. Off by default, so shipped behaviour stays the disposable
# invocation this project has measured. A session that cannot answer falls back to it rather
# than reporting a zero, and what a session returns is the same payload or nothing at all.
# The environment switch exists so a measured run can enable it without changing any default;
# anything other than "1" leaves it off.
session_transport: bool = field(default_factory=lambda: os.environ.get(SESSION_ENV, "").strip() == "1")
_diagnostics: list[str] = field(default_factory=list, init=False, repr=False)
_scratch: list[Path] = field(default_factory=list, init=False, repr=False)
_cancel_deadline: float | None = field(default=None, init=False, repr=False)
_session: EngineSession | None = field(default=None, init=False, repr=False)
_defined: set[str] = field(default_factory=set, init=False, repr=False)
def available(self) -> bool:
from .capability import has_cpg
return has_cpg()
def build(
self, root: Path, *, language: str = "", exclude: Sequence[str] = (), execution_budget: ExecutionBudget | None = None
) -> CpgResult | None:
"""Bind an independent graph session to the caller's absolute transaction deadline."""
budget = execution_budget if execution_budget is not None else self.execution_budget
if budget is None:
return self._build_impl(root, language=language, exclude=exclude)
session = replace(self, execution_budget=budget, last_failure="")
result = None
try:
session._checkpoint()
result = session._build_impl(root, language=language, exclude=exclude)
session._checkpoint()
return result
except _DeadlineExpired:
result = None
return None
finally:
if result is None:
for scratch in session._scratch:
session._cleanup(scratch, final=True)
# This copy owns any engine session it started. Leaving it open leaks a JVM holding the
# configured heap for the life of the process, and two builds per transaction meant two
# of them: enough to exhaust a 3 GB container and make every later request fail.
session.close_session()
self.last_failure = session.last_failure
self._diagnostics = list(session._diagnostics)
def graph_identity(
self,
root: Path,
*,
language: str,
declarations_digest: str,
exclusions_digest: str,
unit: str = "repository",
execution_budget: ExecutionBudget | None = None,
) -> GraphIdentity:
from .artifact import digest_value, read_bytes, source_inventory
budget = execution_budget or self.execution_budget
deadline = budget.deadline_monotonic if budget else float("inf")
version = joern_version()
if version is None:
raise ValueError("engine_identity_unknown")
engine = ".".join(map(str, version))
source, _, _ = source_inventory(root, deadline)
code = digest_value([read_bytes(Path(__file__), deadline).hex(), read_bytes(self.queries_dir / "overlay.sc", deadline).hex()])
return GraphIdentity(
source,
declarations_digest,
exclusions_digest,
unit,
language,
engine,
_FRONTENDS.get(language, "joern-parse"),
engine,
(DATAFLOW_OVERLAY,),
(("implementation", code),),
(
("include_tests", str(self.include_tests)),
("include_build_configs", str(self.include_build_configs)),
(
"installation",
engine_runtime_identity(
include_tests=self.include_tests,
include_build_configs=self.include_build_configs,
language=language,
execution_budget=execution_budget or self.execution_budget,
),
),
("java_options", os.environ.get("JAVA_TOOL_OPTIONS", "default") or "default"),
),
)
def describe_graph(
self, result: CpgResult, root: Path, identity: GraphIdentity, *, execution_budget: ExecutionBudget | None = None
) -> GraphArtifact | None:
"""Seal only a named, complete, single graph census bound to bytes after loading."""
from .artifact import graph_bytes, source_inventory
budget = execution_budget or self.execution_budget
deadline = budget.deadline_monotonic if budget else float("inf")
try:
digest, size, paths = source_inventory(root, deadline)
if digest != identity.source_digest or result.unparsed:
return None
census = result.run("census", {})
if not isinstance(census, Mapping) or DATAFLOW_OVERLAY not in str(census.get("overlays", "")).split(","):
return None
names = census.get("file_names")
if not isinstance(names, list) or not all(isinstance(p, str) for p in names):
return None
normalized = {p.removeprefix(str(root) + "/").removeprefix("./") for p in names}
if not set(paths) <= normalized or int(str(census.get("shards", 1))) != 1:
return None
counts = GraphCensus(*(int(str(census[k])) for k in ("files", "methods", "calls")))
if counts.files < len(paths) or counts.methods < 1:
return None
return GraphArtifact(identity, graph_bytes(result.cpg_path, deadline), size, counts, "complete", (), str(root), paths)
except (OSError, ValueError, KeyError, TimeoutError):
return None
def load_graph(
self,
path: Path,
artifact: GraphArtifact,
expected: GraphIdentity,
*,
execution_budget: ExecutionBudget | None = None,
) -> CpgResult | None:
"""Validate sealed bytes, then query only a disposable private copy."""
from .artifact import IsolatedGraphLease, graph_bytes
budget = execution_budget or self.execution_budget
deadline = budget.deadline_monotonic if budget else float("inf")
cleanup_deadline = deadline + budget.cancellation_allowance_seconds if budget else float("inf")
scratch = None
try:
if artifact.identity != expected or artifact.completeness != "complete" or not artifact.source_paths:
return None
if artifact.census.files < len(artifact.source_paths) or artifact.census.methods < 1:
return None
scratch = Path(tempfile.mkdtemp(prefix="ousast-lease-"))
working = scratch / "cpg.bin"
if graph_bytes(path, deadline, working) != artifact.graph_digest:
raise ValueError("graph_digest_mismatch")
session = replace(self, execution_budget=budget)
lease = IsolatedGraphLease(artifact, working)
def normalize(value: object) -> Any:
if isinstance(value, str):
return value.replace(artifact.source_root + "/", "")
if isinstance(value, list):
return [normalize(item) for item in value]
if isinstance(value, dict):
return {key: normalize(item) for key, item in value.items()}
return value
return CpgResult(
working,
lambda kind, params: normalize(session.query(working, kind, params)),
lambda kind, requests: normalize(session.query_batch(working, kind, requests)),
cleanup=lambda: lease.close(deadline_monotonic=cleanup_deadline),
execution_diagnostics=lambda: tuple(session._diagnostics),
)
except (OSError, ValueError, TimeoutError):
if scratch is not None:
try:
_remove_owned_tree(scratch, cleanup_deadline)
except (OSError, _DeadlineExpired):
self._note("scratch_cleanup_incomplete")
return None
def _build_impl(self, root: Path, *, language: str = "", exclude: Sequence[str] = ()) -> CpgResult | None:
"""Build a CPG for ``root``. ``None`` on any failure — the caller degrades, never guesses.
``language`` lets a failed ``joern-parse`` retry through the frontend directly, which is what Joern
itself advises for a large codebase and what a 637-file WordPress plugin needed.
"""
parse = shutil.which("joern-parse")
if parse is None and os.environ.get("OPENULTRASAST_JOERN_PROBE", "").strip().lower() not in {"1", "on", "true", "yes"}:
return None
if self.execution_budget is None:
_sweep_stale_scratch()
scratch = Path(tempfile.mkdtemp(prefix=SCRATCH_PREFIX))
if self.execution_budget is not None:
self._scratch.append(scratch)
cpg_path = scratch / "cpg.bin"
dispose = lambda: self._cleanup(scratch, final=True) # noqa: E731 -- one expression, named
# THE PRECONDITION. Before anything is built, make the toolchain open one file from the tree and say
# how big it is. Every instrument failure this project has had takes the same shape -- the input was
# unreadable and the tool reported a plausible ZERO -- and it has cost four wrong diagnoses:
#
# a php that could not see ~/.cache -> "php2cpg cannot handle 637 files" (it read none of them)
# a php whose stdio was proxied -> "php2cpg drops half its batches" (it dropped none)
# a container missing a bind mount -> "0 files dropped", 5,703-byte graph
#
# None of those announced themselves. `file_exists()` returns false, the parser writes nothing, the
# frontend exits 0, and "no errors" reads exactly like success. Checking the OUTPUT cannot separate
# those from a genuinely empty repository; checking that the INPUT arrived can, and costs one exec.
unreadable = self._interpreter_cannot_read(root, language)
if unreadable:
logger.error("cpg build refused for %s: %s", root, unreadable)
self.last_failure = unreadable
dispose()
return None
# A frontend whose failures are visible and retryable is worth more than one whose are not.
if language.lower() in _PREFER_FRONTEND:
self.last_failure = ""
shards, unparsed = self._build_sharded(root, scratch, language, exclude=exclude)
if not shards and self.last_failure:
# A build that FAILED BY NAME is not one to retry through the other launcher: the graph the
# census could not load would be rebuilt the same and never asked again.
dispose()
return None
if shards:
if unparsed:
logger.warning("the frontend could not parse %d file(s) under %s: %s", len(unparsed), root, ", ".join(unparsed[:5]))
if len(shards) > 1:
logger.info("querying %d cpg shards for %s; flows that cross them are not visible", len(shards), root)
return CpgResult(
cpg_path=shards[0],
run=lambda query, params: self.query_across(shards, query, params),
run_batch=lambda query, requests: self.query_batch_across(shards, query, requests),
run_batch_once=lambda query, requests: self.query_batch_across(shards, query, requests, once=True),
unparsed=unparsed,
cleanup=dispose,
execution_diagnostics=lambda: tuple(self._diagnostics),
)
if language.lower() in {"javascript", "typescript"}:
# Use the declared frontend rather than language autodetection. The versioned
# retention adaptation consumes the explicit include_tests subprocess policy.
direct = self._build_with_frontend(root, cpg_path, scratch, language, exclude)
if direct is None:
dispose()
return None
self._apply_overlays(cpg_path, scratch)
unparsed = direct
else:
command = [parse or "joern-parse", self._heap_flag(), str(root), "--output", str(cpg_path)]
completed = self._run(command, timeout=self.build_timeout, cwd=scratch)
unparsed = _unparsed_files(completed)
if completed is None or completed.returncode != 0 or not cpg_path.is_file():
detail = (completed.stderr or completed.stdout or "")[-400:] if completed is not None else "timeout"
logger.warning("cpg build failed for %s: %s", root, detail)
retried = self._build_with_frontend(root, cpg_path, scratch, language)
if retried is None:
dispose() # a failed build's scratch is nobody's to sweep six hours later
return None
self._apply_overlays(cpg_path, scratch)
unparsed = retried
if unparsed:
logger.warning("the frontend could not parse %d file(s) under %s: %s", len(unparsed), root, ", ".join(unparsed[:5]))
return CpgResult(
cpg_path=cpg_path,
run=lambda query, params: self.query(cpg_path, query, params),
run_batch=lambda query, requests: self.query_batch(cpg_path, query, requests),
run_batch_once=lambda query, requests: self._batch_once(cpg_path, query, requests),
unparsed=unparsed,
cleanup=dispose,
execution_diagnostics=lambda: tuple(self._diagnostics),
)
def _files_too_large_to_flow(self, root: Path, language: str) -> tuple[str, ...]:
"""Source files over `MAX_SOURCE_BYTES`, relative to the root, in the language the build is about."""
extensions = _LANGUAGE_EXTENSIONS.get(language.lower())
if not extensions:
return ()
found: list[str] = []
for path in self._paths(root, "*"):
if path.suffix.lower() not in extensions or not path.is_file():
continue
try:
if path.stat().st_size > MAX_SOURCE_BYTES:
found.append(str(path.relative_to(root)))
except OSError:
continue
return tuple(found)
def _files_with_frontend_defect(self, root: Path, language: str) -> tuple[str, ...]:
"""Files carrying a construct this frontend miscompiles, found by reading the source.
Excluding a file is a real loss and is only justified when the alternative is losing everything. It
is here: one such file makes the whole graph unqueryable, so the choice is 99.8% of the repository or
none of it. See `_CLOSURE` above for the construct, the reproducer, and the controls.
"""
if language.lower() != "php":
return ()
version = joern_version()
if version is not None and version >= CLOSURE_DEFECT_FIXED_IN:
return () # fixed upstream; nothing to exclude and every file to keep
found: list[str] = []
for path in self._paths(root, "*.php"):
if not path.is_file():
continue
try:
text = path.read_text(errors="ignore")
except OSError:
continue
for match in _CLOSURE.finditer(text):
opening = text.find("{", match.end())
if opening < 0:
continue
depth, index = 0, opening
while index < len(text):
if index % 4096 == 0:
self._checkpoint()
if text[index] == "{":
depth += 1
elif text[index] == "}":
depth -= 1
if depth == 0:
break
index += 1
if _GLOBAL_IN_BODY.search(text[opening:index]):
found.append(str(path))
break
return tuple(found)
def _interpreter_cannot_read(self, root: Path, language: str) -> str:
"""``""`` when the language's interpreter can read the tree, else why not.
Deliberately narrow: it proves one file is openable and non-empty FROM THE INTERPRETER'S OWN VIEW,
which is the thing that differs when `php` is a wrapper, a container without the right bind mount, or
a tree of symlinks pointing somewhere the sandbox cannot follow. Nothing else here can see that
difference, because every other signal is downstream of the parse that never happened.
"""
interpreter = _INTERPRETERS.get(language.lower())
extensions = _LANGUAGE_EXTENSIONS.get(language.lower())
if not interpreter or not extensions:
return ""
binary = shutil.which(interpreter)
if binary is None:
return "" # absent is a different failure, and the frontend reports it plainly
sample = next((path for path in self._paths(root, "*") if path.suffix.lower() in extensions and path.is_file()), None)
if sample is None:
return "" # nothing of this language to read; not the interpreter's fault
probe = "$f = $argv[1]; if (!is_readable($f) || filesize($f) < 1) { exit(3); } exit(0);"
completed = self._run([binary, "-r", probe, str(sample)], timeout=60)
if completed is None:
return f"the {interpreter} interpreter did not respond when asked to read {sample.name}"
if completed.returncode != 0:
return (
f"the {interpreter} interpreter cannot read {sample}, so the frontend would parse nothing and "
f"write an empty graph. Check that {interpreter} is a real interpreter with access to this "
f"tree -- a container or wrapper without the right mount fails exactly this way."
)
# The same question about the frontend's own parser script, which the interpreter also has to open.
frontend = _FRONTENDS.get(language.lower())
relative = _FRONTEND_PARSER.get(language.lower())
frontend_binary = shutil.which(frontend) if frontend else None
if frontend_binary and relative:
parser = Path(frontend_binary).resolve().parent / relative
if parser.is_file():
completed = self._run([binary, "-r", probe, str(parser)], timeout=60)
if completed is not None and completed.returncode != 0:
return (
f"the {interpreter} interpreter cannot read {parser}, the script {frontend} drives it with, "
f"so every file would fail to parse and the graph would be empty. A container or wrapper "
f"that mounts the repository but not this install fails exactly this way."
)
return ""
def _build_sharded(
self, root: Path, scratch: Path, language: str, exclude: Sequence[str] = ()
) -> tuple[tuple[Path, ...], tuple[str, ...]]:
"""Build the tree, and give the files it refuses a CPG of their OWN rather than losing them.
A frontend that drops a file drops it from the only graph there is, and every question about that
file then has no answer -- which is how a 637-file plugin became a scan of nothing. But the same
files build perfectly well on their own: the failure is per-invocation, not per-file. So a file the
main build refuses is excluded from it and put in a second CPG, and the queries run over both.
What this does NOT buy is a flow that crosses the shard boundary. A source in the excluded file and
its sink in the rest of the tree is invisible, and no merging of results can recover it -- which is
why the driver reports the split rather than quietly serving a partial answer.
Returns the CPGs to query and the files that defeated even a shard of their own.
"""
# Excluded from the start, because one of them costs the entire graph rather than itself.
# `exclude` is the caller's: the vendored trees the `[[layout]]` facts put out of scope. This seam
# imports only the standard library, so it is handed the names rather than reading the table.
defective = (*exclude, *self._files_with_frontend_defect(root, language))
if defective:
logger.warning(
"excluding %d file(s) under %s that php2cpg miscompiles (a `global` inside a closure): %s",
len(defective),
root,
", ".join(Path(name).name for name in defective[:5]),
)
oversized = self._files_too_large_to_flow(root, language)
if oversized:
logger.warning(
"excluding %d file(s) under %s over %d bytes (data tables the dataflow overlay never finishes on): %s",
len(oversized),
root,
MAX_SOURCE_BYTES,
", ".join(f"{Path(name).name} ({(root / name).stat().st_size // 1024} KB)" for name in oversized[:5]),
)
defective = (*defective, *oversized)
main = scratch / "cpg.bin"
dropped = self._build_with_retries(root, main, scratch, language, exclude=defective)
if dropped is None:
return (), ()
if not dropped:
# A build that warned about nothing is exactly the build that needs checking, because a graph
# holding nothing arrives with no warnings at all. Silence is the symptom that has no symptom.
census = self._graph_census(main, root, language)
if census is None:
# A graph the census cannot load inside the query timeout cannot answer a taint batch
# either; every one would time out and read as "nothing here". Measured: `cpg query census
# failed: timeout` was logged as a warning during a build whose every later query then
# timed out, and the warning was read as a warning. A build with no usable graph has failed.
self.last_failure = "the graph could not answer the census (timeout or no payload), so no query would be answered either"
logger.error("cpg build for %s: %s", root, self.last_failure)
return (), ()
if census[0] < census[1] - len(defective):
self.last_failure = f"the frontend reported no failures but the graph holds {census[0]} of {census[1]} source files"
logger.error("cpg build for %s: %s", root, self.last_failure)
return (main,), defective
# A warning is a symptom, not a verdict. `php2cpg` logs `Failed to process` for files that are
# nonetheless in the finished graph -- measured: a build reporting two drops produced a graph holding
# both of its files and all 139 methods, the same size as a clean one. Splitting on that evidence is
# actively harmful, because shards cannot see each other's flows: it cost a two-file WordPress pair
# its CVE. So ask the graph before doing anything drastic to it.
if self._graph_is_complete(main, root, language):
logger.info("the frontend warned about %d file(s) under %s but the graph holds them all", len(dropped), root)
return (main,), ()
# Second pass over the same tree, this time telling the frontend to leave the difficult files alone,
# so the rest of the repository is analysed instead of nothing being analysed.
remainder = self._build_with_retries(root, main, scratch, language, exclude=dropped)
shards: list[Path] = []
if remainder is not None and main.is_file():
shards.append(main)
island = self._island_root(root, scratch, dropped)
if island is None:
return tuple(shards), dropped
second = scratch / "cpg-excluded.bin"
still = self._build_with_retries(island, second, scratch, language)
if still is not None and second.is_file():
shards.append(second)
return tuple(shards), tuple(still)
return tuple(shards), dropped
def _graph_census(self, cpg_path: Path, root: Path, language: str) -> tuple[int, int] | None:
"""``(files_in_graph, files_expected)``, or ``None`` when the question cannot be asked.
Always asked, not only when the frontend warned. The dangerous build is the SILENT one: a graph that
holds nothing, reported with no errors at all, which is what an unreadable tree produces and what a
genuinely clean scan of an empty repository looks like. A warning is a symptom; this is the evidence.
"""
extensions = _LANGUAGE_EXTENSIONS.get(language.lower())
if not extensions:
return None
expected = sum(1 for path in self._paths(root, "*") if path.suffix.lower() in extensions and path.is_file())
if not expected:
return (0, 0) # nothing to count is not a failed count: an empty tree's graph is complete
payload = self.query(cpg_path, "census", {})
if not isinstance(payload, Mapping):
return None
self._check_instrument(payload)
try:
return int(str(payload.get("files", "0"))), expected
except ValueError:
return None
def _check_instrument(self, census: Mapping[str, object]) -> None:
"""Two facts the census carries about the engine itself, checked because each was once silently wrong.
A graph whose saved overlays lack the dataflow layer has it recomputed by every query batch -- 54 s
of fixed cost per batch on a 637-file plugin, an OutOfMemoryError on a larger one -- and nothing
else in the pipeline can tell. A worker JVM whose heap is not the configured one means the heap
knob governs nothing, which was true for a day. Both are warnings, not failures: the scan still
runs, slower or smaller, and the log says why. Task 5.13.
"""
overlays = str(census.get("overlays", ""))
if overlays and DATAFLOW_OVERLAY not in overlays.split(","):
logger.warning(
"the graph carries overlays [%s] but not %s: every query batch will recompute the dataflow layer",
overlays,
DATAFLOW_OVERLAY,
)
reported = str(census.get("maxHeapMB", ""))
if reported.isdigit():
configured = self._heap_mb()
if abs(int(reported) - configured) > configured // 4:
logger.warning(
"the query JVM reports a %s MB heap where %d MB is configured; the heap setting is not reaching it",
reported,
configured,
)
def _graph_is_complete(self, cpg_path: Path, root: Path, language: str) -> bool:
"""Conservative: when the census cannot be taken, the answer is "no" and the caller is careful."""
census = self._graph_census(cpg_path, root, language)
return census is not None and census[1] > 0 and census[0] >= census[1]
def _island_root(self, root: Path, scratch: Path, files: Sequence[str]) -> Path | None:
"""A tree holding only ``files``, at their original relative paths.
The paths have to be preserved: a region asks about `classes/class.memberorder.php`, and the queries
match a method's filename by suffix, so a flattened copy would answer about a file nobody asked
about. Symlinks, because the alternative is copying a repository to analyse it.
"""
island = scratch / "excluded-root"
made = 0
for name in files:
self._checkpoint()
source = Path(name)
if not source.is_absolute():
source = root / name
if not source.is_file():
continue
try:
relative = source.relative_to(root)
except ValueError:
relative = Path(source.name)
destination = island / relative
try:
destination.parent.mkdir(parents=True, exist_ok=True)
if not destination.exists():
destination.symlink_to(source)
made += 1
except OSError as exc: # noqa: PERF203 - one bad file must not lose the rest
logger.warning("could not stage %s for its own cpg: %s", source, exc)
return island if made else None
def query_across(self, shards: Sequence[Path], query: str, params: Mapping[str, object]) -> object | None:
"""One question over every shard, answers concatenated. ``None`` only when no shard could answer."""
if query == "census":
return self.query(shards[0], query, params) if len(shards) == 1 else None
merged: list[object] = []
answered = 0
for shard in shards:
rows = self.query(shard, query, params)
if rows is None:
if self.execution_budget is not None:
self._note("shard_query_incomplete")
return None
continue
answered += 1
if isinstance(rows, list):
merged.extend(rows)
return merged if answered else None
def query_batch_across(
self, shards: Sequence[Path], query: str, requests: Mapping[str, Mapping[str, object]], *, once: bool = False
) -> dict[str, list[object]] | None:
"""The batch over every shard, rows concatenated per request id.
The census is summed rather than taken from one shard, and carries the shard count, because
`cpg_empty` has to mean "no graph anywhere" and not "the first of two graphs was small".
``once`` runs a single attempt per shard, for the scan-level portioner that retries itself.
"""
merged: dict[str, list[object]] = {}
methods = 0
files = 0
answered = 0
file_names: set[str] = set()
named_census = True
for shard in shards:
one = self._batch_once(shard, query, requests) if once else self.query_batch(shard, query, requests)
if one is None:
named_census = False
if self.execution_budget is not None:
self._note("shard_query_incomplete")
return None
continue
answered += 1
census = one.pop("__census__", None)
if census and isinstance(census[0], Mapping):
methods += int(str(census[0].get("methods", "0")) or 0)
files += int(str(census[0].get("files", "0")) or 0)
names = census[0].get("file_names")
if isinstance(names, list) and all(isinstance(name, str) for name in names):
file_names.update(names)
else:
named_census = False
else:
named_census = False
for rid, rows in one.items():
merged.setdefault(rid, []).extend(rows)
if not answered:
return None
total: dict[str, object] = {"methods": str(methods), "files": str(files), "shards": str(len(shards))}
if named_census:
total["file_names"] = sorted(file_names)
merged["__census__"] = [total]
return merged
def _apply_overlays(self, cpg_path: Path, scratch: Path) -> bool:
"""Run Joern's default overlays ONCE, at build time, and keep the result in the graph.
A frontend writes a raw graph. Everything that answers a dataflow question -- the call graph, the
type layer, the reaching-definitions pass `OssDataFlow` -- is an OVERLAY, and `importCpg` computes
every overlay the graph lacks each time a JVM opens it. `joern-parse` applies them once and saves;
`php2cpg` output has none, so from the day PHP builds went through the frontend directly
(2026-09-09, 1ce7e9d) every query batch has paid the whole pass again before its first request.
Measured: 54 s of fixed cost per batch on a 637-file plugin, and on WP Statistics the pass alone
ran the default 2 GB heap out of memory after 21 minutes -- a graph the same tool had entailed
CVE-2022-25148 on, one hour before the switch, from a `joern-parse` build. Task 5.13.
`queries/overlay.sc` is that once: `importCpg`, `save`, and the saved graph replaces the raw one
under the same path. (`joern-parse --overlaysonly` is the obvious tool and is broken in 4.0.623: joernio/joern#6283.)
A failure here is logged and the raw graph kept, so the scan degrades to the old cost rather than
losing its graph.
"""
# M2 11.4: the overlay is a whole JVM start, 15.8 s in the measured Node runs, and it is the
# last fixed cost that bypassed the session. `save` writes under the PROCESS working
# directory, which for a session is its own scratch and not this one, so the saved graph is
# looked for in both. Finding neither keeps the raw graph rather than reporting success:
# a graph without its dataflow layer has that layer recomputed by every later batch, 54 s
# each on a 637-file plugin, and nothing would otherwise say so.
session = self._session_for(cpg_path)
workspaces = [scratch / "workspace"]
answered = False
if session is not None:
workspaces.insert(0, session.scratch / "workspace")
body = self._session_payload(cpg_path, "overlay", {"cpgFile": str(cpg_path)})
answered = body is not None and extract_payload(body) is not None
if not answered:
joern = shutil.which("joern")
if joern is None:
return False
script = self.queries_dir / "overlay.sc"
command = [joern, self._heap_flag(), "--script", str(script), "--param", f"cpgFile={cpg_path}"]
completed = self._run(command, timeout=self.build_timeout, cwd=scratch)
answered = completed is not None and completed.returncode == 0 and extract_payload(completed.stdout or "") is not None
if not answered:
detail = (completed.stderr or completed.stdout or "")[-400:] if completed is not None else "timeout"
logger.warning("overlays could not be applied to %s, keeping the raw graph: %s", cpg_path, detail)
saved = next((w / cpg_path.name / "cpg.bin" for w in workspaces if (w / cpg_path.name / "cpg.bin").is_file()), None)
try:
if not answered or saved is None:
if answered:
self._note("overlay_saved_graph_missing")
logger.warning("overlays reported success but saved no graph for %s, keeping the raw graph", cpg_path)
return False
saved.replace(cpg_path)
return True
finally:
for workspace in workspaces:
self._cleanup(workspace)
def _build_with_retries(
self, root: Path, cpg_path: Path, scratch: Path, language: str, exclude: Sequence[str] = ()
) -> tuple[str, ...] | None:
outcome = self._build_with_retries_raw(root, cpg_path, scratch, language, exclude)
if outcome is not None:
self._apply_overlays(cpg_path, scratch)
return outcome
def _build_with_retries_raw(
self, root: Path, cpg_path: Path, scratch: Path, language: str, exclude: Sequence[str] = ()
) -> tuple[str, ...] | None:
"""Build through the frontend, trying again while it reports files it could not parse.
Retrying is only sound because the failure is INTERMITTENT and the frontend says when it happened.
Retrying a silent failure would be superstition; retrying a reported one is just using the report.
The loop stops at the first clean build, and returns the last attempt's dropped files rather than
pretending a partial graph is a whole one.
``None`` means there was nothing to build with, so the caller falls back to ``joern-parse``.
"""
best: tuple[str, ...] | None = None
for attempt in range(FRONTEND_BUILD_ATTEMPTS):
self._checkpoint()
unparsed = self._build_with_frontend(root, cpg_path, scratch, language, exclude)
if unparsed is None:
return best # the frontend is missing or failed outright; keep any earlier partial build
if not unparsed:
return ()
best = unparsed
logger.info(
"frontend dropped %d file(s) on attempt %d of %d for %s; retrying",
len(unparsed),
attempt + 1,
FRONTEND_BUILD_ATTEMPTS,
root,
)
return best
def _build_with_frontend(
self, root: Path, cpg_path: Path, scratch: Path, language: str, exclude: Sequence[str] = ()
) -> tuple[str, ...] | None:
"""Retry the build through the language frontend alone.
Returns the files the frontend dropped -- possibly none -- or ``None`` when there is nothing to retry
with or the retry failed too. An empty tuple and ``None`` are different answers here for the same
reason they are everywhere else in this module: one means "built, and complete", the other means
"could not build".
"""
frontend = _FRONTENDS.get(language.lower())
if not frontend:
return None
binary = shutil.which(frontend)
if binary is None:
logger.warning("no frontend %s on PATH to retry the build for %s", frontend, root)
return None
command = [binary, self._heap_flag(), str(root), "-o", str(cpg_path)]
for name in exclude:
command += ["--exclude", name]
completed = self._run(command, timeout=self.build_timeout, cwd=scratch)
if completed is None or completed.returncode != 0 or not cpg_path.is_file():
detail = (completed.stderr or completed.stdout or "")[-400:] if completed is not None else "timeout"
logger.warning("%s also failed for %s: %s", frontend, root, detail)
return None
logger.info("built the cpg for %s with %s after joern-parse failed", root, frontend)
return _unparsed_files(completed)
def query_batch(self, cpg_path: Path, query: str, requests: Mapping[str, Mapping[str, object]]) -> dict[str, list[object]] | None:
"""Answer many requests, as one invocation where that works and in parts where it does not.
One invocation is the whole point of batching, so it stays the first thing tried and the cost
of a working scan is unchanged. But a batch is all-or-nothing: PMPro's 1,274 PHP files
produced a response the engine could not serialize, failing inside ujson while building its
own answer array, and every question in that batch was lost with it. Three budgets from 900
to 3000 seconds made no difference, because the size of the answer was the problem.
Each request in a batch is independent, so a batch that fails as a whole can still answer in
parts. On failure the requests are split and retried, and a part that fails leaves its own
requests unanswered instead of discarding every answer beside them. Only a batch where no
part answered is reported as unavailable.
"""
if not requests:
return self._batch_once(cpg_path, query, requests)
# What each invocation cost and whether it answered. Nine hypotheses about this cost have been
# eliminated by rebuilding the request outside the driver -- batch size, call depth, parameter
# sources, hook table, argument length, sharding -- and every one of them answered in under four
# minutes while the driver spent whatever ceiling it was given. A scan that issues several
# invocations cannot say which of them burned the budget, and that is why the guessing continued.
started = time.monotonic()
answered = self._batch_once(cpg_path, query, requests)
logger.info(
"cpg batch %s: %d request(s) in %.1fs, %s",
query,
len(requests),
time.monotonic() - started,
"answered" if answered is not None else "unanswered",
)
# Only what is still unanswered is asked again. A streamed batch that was killed hands back every
# answer it finished, so the retry is the REMAINDER, not the batch; and a batch that answered whole
# has no remainder and returns here as it always did.
merged: dict[str, list[object]] = {rid: rows for rid, rows in (answered or {}).items()}
remaining = {rid: req for rid, req in requests.items() if rid not in merged}
if not remaining or len(requests) <= 1:
return answered
if merged:
logger.info(
"cpg batch %s: %d of %d answered before the kill; asking the other %d in parts",
query,
len([k for k in merged if k != "__census__"]),
len(requests),
len(remaining),
)
size = max(1, len(remaining) // _BATCH_SPLITS)
ids = list(remaining)
recovered = bool(answered)
for start in range(0, len(ids), size):
if not self._time_available():
logger.info("cpg batch %s: split abandoned at part %d, no time left", query, start // size + 1)
break
part_started = time.monotonic()
part = self._batch_once(cpg_path, query, {rid: remaining[rid] for rid in ids[start : start + size]})
logger.info(
"cpg batch %s part %d: %d request(s) in %.1fs, %s",
query,
start // size + 1,
min(size, len(ids) - start),
time.monotonic() - part_started,
"answered" if part is not None else "unanswered",
)
if part is None:
continue
recovered = True
for rid, rows in part.items():
merged.setdefault(rid, rows)
if recovered:
self._note("batch_split_after_failure:" + query)
# Requests only. The census rides the answer under its own key and is not a request; counting it
# once printed "22126 of 22125 requests answered", and an instrument that miscounts by one casts
# doubt on every number beside it.
answered_requests = sum(1 for rid in merged if rid in requests)
logger.warning("cpg batch %s failed whole; %d of %d requests answered in parts", query, answered_requests, len(requests))
return merged if recovered else None
def _batch_once(self, cpg_path: Path, query: str, requests: Mapping[str, Mapping[str, object]]) -> dict[str, list[object]] | None:
"""Run ONE script invocation carrying many requests, keyed back to their ids.
JVM startup, not CPG construction, is what dominates a repository scan: every ``joern --script`` call
starts a JVM of roughly thirty seconds, and issuing one per region per family put a ten-line Python
file at four minutes and a thousand regions at about fifty hours. The CPG is already built and loaded
by then; the work itself is milliseconds. So the batch carries the whole scan's questions in one
parameter and the script loops over them.
Fails closed like every other path here, and says which kind of nothing it is: an engine that could
not answer returns ``None`` while a genuine empty answer is ``{}``. That distinction is the whole
point -- "no rows" and "could not ask" look identical to a caller that only sees a dict, and a
117k-line PHP CPG that threw while loading turned a failed scan into a clean bill of health.
"""
if not self._time_available():
return None
script = self.queries_dir / f"{query}.sc"
if not script.is_file():
logger.warning("no such cpg query: %s", script)
return None
rendered = {rid: {k: _render(v) for k, v in req.items()} for rid, req in requests.items()}
shared = _hoist_shared(rendered)
payload = json.dumps(rendered)
# Through a FILE, never the command line. Linux caps a single argument at MAX_ARG_STRLEN (128KB)
# whatever ARG_MAX says, and a repository blows through that: 2500 taint requests over a 637-file
# WordPress plugin is a 1.49MB payload. execve returns E2BIG, `_run` catches the OSError, this returns
# {} -- and {} reads as "no rows found". The scan reported 500 regions examined and nothing found, in
# 0.05 seconds of taint query, which is a quiet failure of exactly the kind the rung ladder cannot
# catch because no verdict was ever produced to label.
if not self._time_available():
return None
requests_file = cpg_path.parent / f"{query}-requests-{len(rendered)}-{abs(hash(tuple(sorted(rendered)))) % 10**8}.json"
try:
requests_file.write_text(payload)
except OSError as exc:
logger.warning("could not stage cpg batch %s: %s", query, exc)
return None
# The session answers the same script with the same parameters, or nothing; nothing means
# the disposable invocation below runs exactly as it always has.
body = self._session_payload(cpg_path, query, {"cpgFile": str(cpg_path), "requestsFile": str(requests_file), **shared})
if body is None:
command = [
shutil.which("joern") or "joern",
self._heap_flag(),
"--script",
str(script),
"--param",
f"cpgFile={cpg_path}",
"--param",
f"requestsFile={requests_file}",
]
for name, value in shared.items():
command += ["--param", f"{name}={value}"]
completed = self._run(command, timeout=self.query_timeout, cwd=cpg_path.parent)
harvested = completed is not None and completed.returncode != 0 and BEGIN in (completed.stdout or "")
if completed is None or (completed.returncode != 0 and not harvested):
detail = _engine_failure(completed)
logger.warning("cpg batch %s failed: %s", query, detail)
return None
body = completed.stdout or ""
parsed = extract_payload(body)
if not self._time_available():
return None
if not isinstance(parsed, Mapping):
# Unparseable output is a failure, not an empty answer. A 117k-line PHP CPG that throws while
# loading printed a stack trace and no payload, and returning {} made the whole scan read as a
# clean repository -- 500 regions examined, nothing found, no degradation recorded.
logger.warning("cpg batch %s returned no parseable payload", query)
return None
if parsed.get(PARTIAL):
answered = sum(1 for rid, rows in parsed.items() if rid != PARTIAL and isinstance(rows, list) and rid != "__census__")
logger.info("cpg batch %s was killed with %d of %d answer(s) already streamed", query, answered, len(requests))
# A request the engine did not answer is absent, not empty: the caller must be able to tell them apart.
return {str(rid): list(rows) for rid, rows in parsed.items() if rid != PARTIAL and isinstance(rows, list)}
def query(self, cpg_path: Path, query: str, params: Mapping[str, object]) -> object | None:
"""Run a shipped CPGQL script against a built CPG and return its fenced JSON payload."""
if not self._time_available():
return None
script = self.queries_dir / f"{query}.sc"
if not script.is_file():
logger.warning("no such cpg query: %s", script)
return None
body = self._session_payload(cpg_path, query, {"cpgFile": str(cpg_path), **params})
if body is None:
command = [shutil.which("joern") or "joern", self._heap_flag(), "--script", str(script), "--param", f"cpgFile={cpg_path}"]
for key, value in sorted(params.items()):
command += ["--param", f"{key}={_render(value)}"]
# Joern writes a `workspace/` beside the working directory; run it inside the CPG's own scratch dir so
# it can never land in the repository being analysed.
completed = self._run(command, timeout=self.query_timeout, cwd=cpg_path.parent)
if completed is None or completed.returncode != 0:
detail = _engine_failure(completed)
logger.warning("cpg query %s failed: %s", query, detail)
return None
body = completed.stdout or ""
parsed = extract_payload(body)
return parsed if self._time_available() else None
def _session_for(self, cpg_path: Path) -> EngineSession | None:
"""The transaction's session, started on first use. None means use the disposable path."""
if not self.session_transport or self.execution_budget is None:
return None
if self._session is not None:
return self._session if self._session.alive else None
session = EngineSession(cpg_path.parent / "engine-session", self.execution_budget, self._jvm_env())
if not session.start():
self._note("session_unavailable:" + (session.failure or "unknown"))
session.close()
self._session = session
return None
self._session = session
return session
def _session_payload(self, cpg_path: Path, query: str, params: Mapping[str, object]) -> str | None:
"""Run one shipped script in-session and return what it printed, or None to fall back.
The script is defined under a name of its own because every script declares `exec`, and a
second definition would shadow the first. Defining proves nothing: the receipt on the call
is the only proof, which is why any failure here simply falls back to the disposable path.
"""
session = self._session_for(cpg_path)
if session is None:
return None
try:
source = (self.queries_dir / f"{query}.sc").read_text()
except OSError:
return None
symbol = f"ousast_{query}"
if query not in self._defined:
if session.define(source.replace("@main def exec(", f"def {symbol}(", 1), timeout=self.query_timeout) is None:
self._note("session_define_failed:" + query)
return None
self._defined.add(query)
arguments = ", ".join(f"{name} = {json.dumps(_render(value))}" for name, value in sorted(params.items()))
answer = session.evaluate(f"{symbol}({arguments})", timeout=self.query_timeout)
if answer is None:
# Carry the engine's own account, not just our label: a bare `session_request_failed`
# cannot distinguish a timeout from a crash from an out-of-memory kill.
# 500 characters was not enough: a Scala stack trace is longer than that, so the window
# showed only frames and cut off the exception that names the cause.
detail = (session.last_body or session.log_tail())[-2000:].replace("\n", " ")
self._note("session_query_failed:" + query + ":" + (session.failure or "unknown"))
logger.warning("session query %s failed (exit=%s): %s", query, session.exit_code(), detail)
return None
return answer.stdout
def close_session(self) -> None:
"""End the transaction's session and reap its process group."""
if self._session is not None:
self._session.close()
self._session = None
self._defined.clear()
def _note(self, reason: str) -> None:
if reason not in self._diagnostics:
self._diagnostics.append(reason)
self.last_failure = reason
def _time_available(self) -> bool:
if self._cancel_deadline is not None:
return False
if self.execution_budget is not None and time.monotonic() >= self.execution_budget.deadline_monotonic:
self._note("deadline_exhausted")
return False
return True
def _checkpoint(self) -> None:
if not self._time_available():
raise _DeadlineExpired
def _paths(self, root: Path, pattern: str): # type: ignore[no-untyped-def]
paths = root.rglob(pattern)
if self.execution_budget is None:
yield from sorted(paths)
else:
self._checkpoint()
for path in paths:
self._checkpoint()
yield path
def _cleanup_limit(self) -> float:
assert self.execution_budget is not None
ceiling = self.execution_budget.deadline_monotonic + self.execution_budget.cancellation_allowance_seconds
return min(ceiling, self._cancel_deadline) if self._cancel_deadline is not None else ceiling
def _cleanup(self, root: Path, *, final: bool = False) -> None:
if self.execution_budget is None:
shutil.rmtree(root, ignore_errors=True)
return
deadline = self._cleanup_limit() if final or self._cancel_deadline is not None else self.execution_budget.deadline_monotonic
try:
_remove_owned_tree(root, deadline)
except (OSError, _DeadlineExpired):
self._note("scratch_cleanup_incomplete")
def _run_bounded(self, command: list[str], *, timeout: float, cwd: Path | None) -> subprocess.CompletedProcess[str] | None:
assert self.execution_budget is not None
if not self._time_available():
return None
remaining = min(timeout, self.execution_budget.deadline_monotonic - time.monotonic())
if remaining <= 0:
self._note("deadline_exhausted")
return None
process = None
terminated = False
try:
if self.runner is not None:
result = self.runner(command, capture_output=True, text=True, timeout=remaining, check=False, cwd=str(cwd) if cwd else None)
else:
process = subprocess.Popen( # noqa: S603 -- internal argument array
command,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
text=True,
cwd=str(cwd) if cwd else None,
env=self._jvm_env(),
start_new_session=True,
)
remaining = min(remaining, max(0.0, self.execution_budget.deadline_monotonic - time.monotonic()))
stdout, stderr = process.communicate(timeout=remaining)
result = subprocess.CompletedProcess(command, process.returncode, stdout, stderr)
if not self._time_available():
return None
return result
except subprocess.TimeoutExpired as expired:
# What the process had already written is kept, because a streamed answer is worth exactly the
# lines that finished. `communicate` raises without returning them, so they are drained after
# the kill -- see `_partial_stdout`, which reads what the pipe still holds.
# Two different timeouts end here and they must not have the same consequence. If the SCAN's
# deadline is gone, cancellation is right: stop everything promptly, which is what the push's
# two-second gate measures. If a single query merely exceeded its own ceiling, the scan may have
# most of its budget left and every other batch is independent and cheaper -- and cancelling took
# them all. Measured 2026-09-22: one batch of 116 requests hit a 300 s ceiling 734 s into a
# 2,700 s scan, and the four batches behind it returned in 0.0 s unanswered with 33 minutes to
# spare. Fourth instance of one rule this week: a failure is owned by the narrowest scope that
# caused it.
exhausted = time.monotonic() >= self.execution_budget.deadline_monotonic
if exhausted:
self._cancel_deadline = min(self._cleanup_limit(), time.monotonic() + self.execution_budget.cancellation_allowance_seconds)
self._note("deadline_exhausted" if exhausted else "process_timeout")
# The group is killed BEFORE its output is read. A first cut read the pipe first, and a pipe whose
# writer is still alive never reaches end-of-file: the suite's own hanging-engine control sat on
# that read for twenty-eight minutes. Once the group is dead, `communicate` returns promptly with
# everything the pipe still held.
if process is not None:
if not _terminate_bounded_group(process, self._cleanup_limit()):
self._note("process_cleanup_incomplete")
terminated = True
partial = _partial_stdout(expired, process)
if partial:
# A killed process whose output holds finished answers is not nothing. The negative return
# code says it was killed; the stdout says what it finished; `_batch_once` reads both.
return subprocess.CompletedProcess(command, -1, partial, "")
return None
except (OSError, subprocess.SubprocessError):
self._note("process_failed")
return None
finally:
if process is not None and not terminated:
# No Popen context manager: its implicit wait has no timeout. Always signal
# the original group ID, even if the launcher already exited, so descendants
# retaining pipes (or closing them) cannot survive it.
if not _terminate_bounded_group(process, self._cleanup_limit()):
self._note("process_cleanup_incomplete")
for stream in (process.stdout, process.stderr):
if stream is not None:
stream.close()
def _heap_mb(self) -> int:
if self.heap_mb > 0:
return self.heap_mb
configured = os.environ.get(HEAP_ENV, "").strip()
return int(configured) if configured.isdigit() else CPG_HEAP_MB
def _heap_flag(self) -> str:
"""``-J-Xmx``: both launchers forward ``-J`` arguments to the JVM they start."""
return f"-J-Xmx{self._heap_mb()}m"
def _jvm_env(self) -> dict[str, str]:
"""The heap for the JVM that does the work, which is NOT the one ``-J`` reaches.
``joern --script`` starts a launcher JVM and forks a second one to run the script
(``replpp.scripting.NonForkingScriptRunner``, despite the name), and the ``-J-Xmx`` goes to the
launcher only: 163 MB resident, next to a worker with no ``-Xmx`` at all sitting at 2.26 GB -- the
JVM default of a quarter of physical memory. So ``OPENULTRASAST_CPG_HEAP_MB`` governed nothing on an
8 GB machine and would silently take 16 GB on a 64 GB one. ``JAVA_TOOL_OPTIONS`` is read by every
JVM at start-up, forked ones included, and is appended to rather than replaced so an operator's own
options survive.
"""
env = dict(os.environ)
env["OUSAST_INCLUDE_TESTS"] = "1" if self.include_tests else "0"
env["OUSAST_INCLUDE_BUILD_CONFIGS"] = "1" if self.include_build_configs else "0"
env["JAVA_TOOL_OPTIONS"] = f"{env.get('JAVA_TOOL_OPTIONS', '').strip()} -Xmx{self._heap_mb()}m".strip()
return env
def _run(self, command: list[str], *, timeout: int, cwd: Path | None = None) -> subprocess.CompletedProcess[str] | None:
"""Run one Joern command, and on timeout kill the whole PROCESS GROUP rather than the child.
`joern` and `joern-parse` are shell scripts that launch a JVM as a separate process. Killing the
script -- which is all `subprocess.run(timeout=)` does -- leaves that JVM running, holding its heap,
for as long as the machine lasts. Every `query_failed: timeout` leaked about a gigabyte.
Measured the hard way: after a day of 300s and 2,400s taint timeouts, four orphaned JVMs three hours
old were still resident and the machine ran out of memory. On a CI runner doing several scans in a
row it would OOM rather than merely degrade -- and it would look like the SCAN needing more memory,
which is the wrong lesson entirely.
"""
if self.execution_budget is not None:
return self._run_bounded(command, timeout=timeout, cwd=cwd)
run = self.runner if self.runner is not None else subprocess.run
if self.runner is not None: # tests inject a fake runner and never spawn anything
try:
return run(command, capture_output=True, text=True, timeout=timeout, check=False, cwd=str(cwd) if cwd else None)
except (OSError, subprocess.SubprocessError):
return None
try:
with subprocess.Popen( # noqa: S603 -- the command is built here, never from user input
command,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
text=True,
cwd=str(cwd) if cwd else None,
env=self._jvm_env(),
start_new_session=True, # its own process group, so the JVM dies with the script
) as process:
try:
stdout, stderr = process.communicate(timeout=timeout)
except subprocess.TimeoutExpired:
_terminate_group(process)
return None
return subprocess.CompletedProcess(command, process.returncode, stdout, stderr)
except (OSError, subprocess.SubprocessError):
return None
class _DeadlineExpired(Exception):
"""Internal cooperative boundary; public builds/queries retain failure semantics."""
def _partial_stdout(expired: subprocess.TimeoutExpired, process: subprocess.Popen[str] | None) -> str:
"""Whatever the killed process had written, from the exception and then from the pipe itself.
`communicate(timeout=)` raises with the output it had buffered so far, but a pipe can hold more than the
buffer had drained by the time the timer fired. After the group is killed the pipe has nothing left to
wait on, so a final read returns the rest without blocking.
"""
output = expired.output if isinstance(expired.output, str) else (expired.output.decode(errors="replace") if expired.output else "")
if process is None:
return output
# Only valid once the group is dead; the caller guarantees that. `communicate` on a finished process
# returns whatever the pipes still held and does not wait on anything.
try:
rest, _ = process.communicate(timeout=1.0)
except (subprocess.TimeoutExpired, OSError, ValueError):
return output
rest_text = rest if isinstance(rest, str) else (rest.decode(errors="replace") if rest else "")
return rest_text if rest_text else output
def _terminate_bounded_group(process: subprocess.Popen[str], deadline: float) -> bool:
# SIGKILL immediately leaves the shared allowance for reaping and scratch cleanup.
# Unlike the legacy TERM/wait loop this also kills grandchildren after leader exit.
try:
os.killpg(process.pid, signal.SIGKILL)
except ProcessLookupError:
pass
except OSError:
return False
try:
process.wait(timeout=max(0.0, deadline - time.monotonic()))
except subprocess.TimeoutExpired:
return False
return True
def _remove_owned_tree(root: Path, deadline: float) -> None:
"""Bounded Linux dirfd cleanup, never following substituted directory links."""
def check() -> None:
if time.monotonic() >= deadline:
raise _DeadlineExpired
def contents(fd: int) -> None:
with os.scandir(fd) as entries:
for entry in entries:
check()
info = os.stat(entry.name, dir_fd=fd, follow_symlinks=False)
if stat.S_ISDIR(info.st_mode):
child = os.open(entry.name, os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW, dir_fd=fd)
try:
contents(child)
finally:
os.close(child)
check()
os.rmdir(entry.name, dir_fd=fd)
else:
os.unlink(entry.name, dir_fd=fd)
if not root.exists() and not root.is_symlink():
return
check()
if root.is_symlink():
root.unlink()
return
fd = os.open(root, os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW)
try:
contents(fd)
finally:
os.close(fd)
check()
root.rmdir()
SCRATCH_PREFIX = "ousast-cpg-"
# How long an abandoned scratch tree may survive. Long enough that a scan running in another process is never
# disturbed, short enough that a machine scanning all day does not fill its disk.
SCRATCH_MAX_AGE_SECONDS = 6 * 60 * 60
def _sweep_stale_scratch() -> None:
"""Remove scratch trees older than `SCRATCH_MAX_AGE_SECONDS`, best effort and never fatal.
Belt as well as braces: `cleanup` disposes of a scan's own tree, but a process killed mid-scan -- which
is how most of them died here -- never runs its `finally`. Only directories under the system temp root
carrying this module's own prefix are touched.
"""
root = Path(tempfile.gettempdir())
cutoff = time.time() - SCRATCH_MAX_AGE_SECONDS
try:
candidates = list(root.glob(f"{SCRATCH_PREFIX}*"))
except OSError:
return
for path in candidates:
try:
if path.is_dir() and path.stat().st_mtime < cutoff:
shutil.rmtree(path, ignore_errors=True)
except OSError: # noqa: PERF203 -- one unreadable entry must not stop the sweep
continue
def _terminate_group(process: subprocess.Popen[str]) -> None:
"""SIGTERM the process group, then SIGKILL what is left. Never raises: this is cleanup, not logic."""
for signal_number in (signal.SIGTERM, signal.SIGKILL):
try:
os.killpg(os.getpgid(process.pid), signal_number)
except (OSError, ProcessLookupError):
return
try:
process.wait(timeout=10)
return
except subprocess.TimeoutExpired:
continue
# Every Joern frontend logs a dropped file the same way, at WARN, and then carries on:
#
# WARN AstCreationPass Failed to process '/abs/path/to/file.php'
#
# The quotes are part of the line, which is what makes this safely greppable rather than a guess at column
# positions. Several passes report the same file, so the caller de-duplicates.
_UNPARSED = re.compile(r"Failed to process '([^']+)'")
def _unparsed_files(completed: subprocess.CompletedProcess[str] | None) -> tuple[str, ...]:
"""The files the frontend read and dropped, in first-seen order.
This exists because a Joern frontend fails a file WITHOUT failing the build. `php2cpg` 4.0.623 feeds
several files to one `php-parse` process and reads its stdout and stderr merged; php-parse writes a
`====> File <next>:` banner to stderr the moment it starts the next file, while the previous file's JSON
-- megabytes of it -- is still draining from a block-buffered stdout. The banner lands inside the JSON,
ujson reports `expected json value got "="`, and the frontend drops that file. Reproducibly, on real
plugin code:
one 1834-line file alone -> a 142KB CPG, no failures
the same file plus a two-line file -> a 5.7KB CPG, BOTH files dropped, exit status 0
So the size that matters is one file's AST dump, not the repository's, and one oversized file can empty
the whole graph. Before this, that arrived as a scan reporting no findings and no degradations -- a clean
bill of health over a graph containing nothing at all.
"""
if completed is None:
return ()
seen: dict[str, None] = {}
for stream in (completed.stdout or "", completed.stderr or ""):
for match in _UNPARSED.finditer(stream):
seen.setdefault(match.group(1), None)
return tuple(seen)
def _hoist_shared(rendered: dict[str, dict[str, str]]) -> dict[str, str]:
"""Pull the repository-wide fields out of every request, returning them once.
A field only lifts if it is IDENTICAL across the whole batch, so a value that genuinely varies per
region stays where it belongs and nothing is silently shared between questions.
"""
if not rendered:
return {}
shared: dict[str, str] = {}
for name in _SHARED_REQUEST_FIELDS:
values = {request.get(name, "") for request in rendered.values()}
if len(values) == 1:
value = values.pop()
if value:
shared[name] = value
for request in rendered.values():
request.pop(name, None)
return shared
def _configured_timeout() -> int:
"""The query ceiling, from the environment or the default. Never zero or negative."""
raw = os.environ.get(QUERY_TIMEOUT_ENV, "").strip()
if raw.isdigit() and int(raw) > 0:
return int(raw)
return QUERY_TIMEOUT_SECONDS
def _engine_failure(completed: subprocess.CompletedProcess[str] | None) -> str:
"""What the engine said, keeping the line that names the cause.
A stack trace's exception is on its FIRST line and its frames follow, so logging only the tail
reports frames and discards the cause. Four PHP investigations were spent on `cpg batch taint
failed: dure1.java:10)`, which is the middle of a frame and says nothing at all.
"""
if completed is None:
return "timeout"
text = (completed.stderr or completed.stdout or "").strip()
if not text:
return f"exit {completed.returncode} with no output"
lines = [line for line in text.splitlines() if line.strip() and not line.strip().startswith("at ")]
head = " | ".join(lines[:4])[:600]
return head or text[:300]
def _render(value: object) -> str:
"""CPGQL parameters are strings; a sequence becomes a comma-separated list the script splits."""
if isinstance(value, str):
return value
if isinstance(value, (list, tuple, set, frozenset)):
return ",".join(sorted(str(item) for item in value))
return str(value)
def resolve_cpg_backend(*, runner: Runner | None = None) -> CpgBackend:
"""The backend for this machine: Joern when it is installed, else the null one."""
from .capability import has_cpg
return JoernBackend(runner=runner) if has_cpg() else NullBackend()
__all__ = [
"BEGIN",
"END",
"CpgBackend",
"CpgResult",
"JoernBackend",
"NullBackend",
"extract_payload",
"resolve_cpg_backend",
]