Open_Ultra_SAST/.kiro/specs/contributor-scan/tasks.md

# Implementation Plan: contributor-scan

## Guidance for the implementing agent

- **The predecessor's lesson, in one line.** Five bugs in `model-grounded-detection` shared one shape: a
  taint-specific assumption applied to every family, each caught by a *measurement* rather than a check.
  Before you finish any change to a routing rule, a matching rule, or a per-family question, **grep for its
  siblings and fix them in the same commit.** The most expensive instance cost a 19-minute run that returned
  an identical number, and only the identity revealed the bug.
- **Run the whole CI list before pushing**, not the parts you remember: `ruff format --check .`,
  `ruff check .`, `mypy src/openultrasast`, `pytest`, the three gates, `compileall src tests`, and
  `pytest -m semantic`. CI was red for most of a session because `ruff check` passing was taken as evidence
  that `ruff format --check` would.
- **The gate baseline is the safety net.** `benchmarks/measurements/2026-09-06-gate-baseline.txt`. Run all
  three gates before and after every task. The model layer is additive: if a gate moves, you changed
  something that was never meant to change.
- **RED first**, one commit per task, selective `git add`.
- **Zero-dependency core.** Copy the capability-probe pattern in `semantic/extra.py` and `cpg/capability.py`.
- **Do not modify `model/pipeline`, `taint`, `dominance`, `config_value`, `specs` or `candidates`.** They are
  built and measured. If a change looks necessary, it belongs in its own commit with its own measurement.

## Group 1 — Wire it (gate-protected)

- [x] 1.1 Regions from entry points
  - `model/regions.py`: `ScanRegion(path, function, families, rank, source)` and
    `regions_for(entries, targets, *, taxonomy, language_of)`. Rank from what `EntryPointRecord` already
    carries (`access_level`, `trust_boundary`) — do not invent a new signal. File-level fallback when a target
    has no entry point, with `source="file_fallback"`. Families from region shape and language, via the
    existing `taint_specs`/`dominance_specs`/`config_specs`.
  - **Sibling audit (Req 8.5):** family routing now exists in three places — `ceiling.py`'s harness,
    `pipeline._arbitrate`, and here. Check all three agree before finishing.
  - Observable: a region is produced per entry point; a target with no entry point yields a file region marked
    as such; no region carries a family whose spec is absent for its language.
  - _Requirements: 2.1, 2.2, 2.3, 2.4, 8.5_

- [x] 1.2 The repository driver
  - `model/scan.py`: `ScanBudget`, `ModelScanResult`, `scan_repository(...)`. **One CPG per run**, reused
    across regions. Regions in rank order; budget decremented per model call and checked before each; the
    remainder counted into `regions_unjudged`. Findings ordered by rung, then rank.
  - Observable: one `backend.build` call for many regions; a budget of N yields at most N model calls and a
    non-zero `regions_unjudged`; ordering puts `model_entailed` above `suspicion`; a failed CPG build yields
    an empty result with `cpg_build_failed`, never an exception.
  - Redaction (Req 8.3) is inherited from `model/pipeline`, which redacts every prompt; a test asserts the
    driver adds no unredacted path of its own.
  - _Requirements: 3.1, 3.2, 3.3, 3.4, 3.5, 8.3_
  - _Depends: 1.1_

- [x] 1.3 The MAP stage
  - Wire `scan_repository` into `cli.py` inside `Stage.MAP`, mirroring `_check_obligations`: takes
    `entry_points` and `targets`, returns findings merged **additively** beside the pattern, overlay and
    obligation findings. A `[model]` config block (enabled, budget, max regions), zero-dep, conservative
    defaults. Payload into the manifest with `by_rung`, cost and elapsed.
  - Observable: a scan on a repo with Joern present reports findings carrying rungs; the same scan with
    `OPENULTRASAST_JOERN_PROBE=off` is identical to today's output plus a `cpg_unavailable` degradation;
    **the three gates are byte-identical**.
  - The `[model]` block is capability-detected like every other optional plane (Req 8.4): core stays
    `dependencies = []`, and the engine, endpoint and execution tier each degrade to a recorded reason.
  - _Requirements: 1.1, 1.2, 1.3, 1.4, 1.5, 8.4_
  - _Depends: 1.2_

- [x] 1.4 Batch the queries — one Joern invocation per scan, not one per region and family
  - **Why this is in group 1 rather than group 2.** Wiring 1.3 exposed that the cost model in the design was
    half right. One CPG per scan was the right call, but every *query* is its own `joern --script` JVM launch
    of roughly 30 seconds, and the driver issues one per region per family. A single ten-line Python file
    admits six families and therefore takes six launches and over three minutes. At 100 regions that is ~5
    hours; at 1000, ~50. Task 2.2's go/no-go would not have been a measurement, only arithmetic.
  - Extend `cpg/backend.py` with a batched call: one invocation carrying many (region, family, spec) requests
    and returning rows keyed back to each. The `.sc` scripts already take parameter lists; they take a list of
    requests instead. `model/scan.py` collects the work first, issues one call, then arbitrates from the rows.
  - **Keep the seam.** The subprocess boundary stays the only Joern touch-point (predecessor Req 4.5). Server
    mode would keep a JVM warm but adds a process model and weakens that promise; batching needs neither.
  - **The arbiters do not change.** `taint`, `dominance`, `config_value` and `pipeline` take rows and are
    already measured; if this task needs to edit one, that is a signal the batching is leaking into them.
  - Observable: a scan over N regions issues **one** `joern --script` invocation, not N×families; the same
    fixture produces the same findings and rungs as the unbatched path, asserted against a recorded baseline;
    the ten-line scan drops from minutes to seconds.
  - _Requirements: 3.5, 4.2, 4.3_
  - _Depends: 1.3_

## Group 2 — Scale it (the phase that can reshape the rest)

- [x] 2.1 A pinned known-vulnerable checkout
  - `benchmarks/repos/<name>.toml`: url, commit, the known CVE, the file and function it lives in, licence.
    Start with one small enough to iterate on. Fetch is explicit and offline-by-default, like the pointer
    pairs.
  - Observable: the recipe resolves to a checkout; CI never fetches it.
  - _Requirements: 4.1_
  - _Depends: 1.3_

- [x] 2.2 The first repository measurement
  - Run the full scan against that checkout and commit the artifact: CPG build time, query time and total
    scan wall-clock as three separate numbers, peak memory, findings by rung, cost, `regions_unjudged`,
    and **whether the known CVE was found and at which rung**. The build/query split is separated because
    2.3 is decided on that ratio and cannot be decided on a single wall-clock figure. If the repository cannot be processed in its envelope, record the stage it failed at.
  - This is the go/no-go for the shape of the rest: if one CPG per repository is infeasible, the region and
    budget design changes and phases 3–6 should not be built on it first.
  - Observable: the artifact exists with every field; the reading states go or no-go and why.
  - _Requirements: 4.2, 4.3, 4.4, 4.5_
  - _Depends: 2.1_

- [x] 2.3 Decide on Joern server mode, on 2.2's numbers
  - Joern offers `--server` with `--server-host`, `--server-port` and basic auth: one warm JVM with the CPG
    loaded once, and queries in milliseconds after that. It would remove the three-to-four JVM starts
    (~100s) that remain per scan now that 1.4 has batched the queries.
  - **Deliberately sequenced after the measurement, because deciding it now would be optimising before
    measuring.** Batching already moved query cost from O(regions) to O(1) per scan; whether the remaining
    floor matters is a ratio 2.2 produces and nothing before it does. If a real CPG build takes ten minutes,
    a 100s query floor is noise and server mode buys nothing. If the build is thirty seconds, the floor is
    3x the build and server mode is the obvious next move.
  - Costs to weigh against that ratio: process lifecycle (start, health, shutdown, orphan reaping -- stray
    JVMs had to be killed by hand twice while building the batching); the seam weakening from "the subprocess
    is the only Joern touch-point" to "subprocess or HTTP client", which is the promise that has kept the
    backend replaceable; and that a CPGQL endpoint evaluates Scala, so it is arbitrary code execution on the
    analysis host -- acceptable inside the shipped container, which runs `network_mode: none`, and much less
    so as a port listening on a contributor's laptop.
  - Observable: a recorded decision that cites 2.2's build-time-to-query-time split. A preference does not
    close this task; a ratio does.
  - **Decided: no.** On libpng (89k lines of C) the query phase splits taint 243.3s / config 10.7s over two
    invocations, and fixed overhead measured on that CPG is ~13s per invocation. So ~26s of 250s is JVM
    startup and ~224s is CPGQL evaluation: a warm server removes 6% of a 446s scan and none of the part that
    costs. Recorded in `benchmarks/measurements/2026-09-09-repo-libpng-envelope.json`.
  - The small repository pointed the other way -- vampi's 34.3s over three kinds is roughly three startups
    and almost no evaluation -- and the ratio inverts with size. That inversion is precisely why this task
    was sequenced after a real repository instead of being decided on a 520-line file.
  - _Requirements: 4.2_
  - _Depends: 2.2_

- [x] 2.4 A region that spans the flow, not just a function
  - **2.2's finding, and the one that reshapes the phase.** VAmPI-SQLI is a request parameter reaching
    `get_by_username(username)`, passed to `User.get_user(username)` in another module, interpolated into a
    query and executed. Source and sink are in different functions, regions are per-function, and a
    repository scan does not treat parameters as untrusted -- so neither region sees both ends and the
    engine is silent on the most ordinary shape a real injection bug has.
  - The CPG already has the call graph; `reachableByFlows` is not function-bounded. What is bounded is the
    QUESTION the driver asks. So the work is in the region model and the query scope, not in the arbiter:
    a region should be able to name an entry point and admit sinks reachable from it, with the file scope
    from 2.2 kept so the answer is still attributable.
  - Watch the cost: an unbounded interprocedural question over a large repository is how this gets slow
    again. Measure it on vampi first, then on the envelope checkout.
  - Observable: VAmPI-SQLI entailed or corroborated at `models/user_model.py:get_user`, with the scan's
    wall-clock and the entailed-finding count recorded against 2.2's numbers.
  - _Requirements: 4.4, 8.1_
  - _Depends: 2.2_

- [x] 2.5 Module-level regions the engine can actually ask about
  - A setting in `if __name__ == '__main__':` belongs to a region the mapper calls `app.py:__main__`, but
    Joern names that method `<module>`. The function filter matches nothing, so module-level configuration
    is invisible. Before 2.2's file scoping it was worse, not better: the literal was reported eight times
    in eight files that do not contain it.
  - Observable: `app.py:17`'s `host='0.0.0.0'` reported exactly once, at that location.
  - _Requirements: 4.4_
  - _Depends: 2.2_

- [x] 2.6 Access control that does not entail every public endpoint
  - 7 of 9 VAmPI handlers were entailed, including `register_user` and `get_all_users`, which are meant to
    be unauthenticated. The dominance rule -- unguarded, with guarded siblings -- was calibrated on pairs
    where a guarded twin always existed. At repository scale every public endpoint has guarded siblings.
  - This is a precision question and needs a precision measurement: on a real repository, what fraction of
    entailed access-control findings are endpoints that genuinely require authorisation? Do not tune it
    against VAmPI alone; that is how the +16% overfitting gap in Req 8 happened.
  - Observable: a recorded precision figure before and after, on more than one checkout.
  - _Requirements: 8.1, 8.2_
  - _Depends: 2.2_

- [x] 2.7 A dominance witness that names its line
  - Access-control sites read `api_views/users.py:?:update_password`. Taint and config witnesses carry
    `(line N)`; dominance does not, so its findings have no line and a contributor cannot open them.
  - Observable: every entailed finding in a repository scan has an integer line.
  - _Requirements: 5.1_
  - _Depends: 2.2_

- [x] 2.8 An endpoint that declares itself public carries no obligation
  - **2.6's remainder.** Both false positives left on VAmPI are `register_user` and `login_user`, which its
    OpenAPI spec declares public with no `security` block. The arbiter cannot see that declaration, so it
    reports a missing guard on an endpoint whose contract says there is nothing to miss.
  - The mapper's `access_level` is NOT a safe substitute on its own. For an OpenAPI route it comes from the
    declared `security` block and is trustworthy; for a decorator-based framework "public" means only that
    no `@login_required` was found, which is precisely the bug this family exists to report. Suppressing on
    that would silence the primary detection case for Flask and Express.
  - So the work is to carry the PROVENANCE of the access level, not just its value: a declared contract
    removes the obligation, an absent decorator does not. `EntryPointRecord.provenance` currently only
    echoes the level, so this needs a real signal rather than a string match on evidence text.
  - Observable: `register_user` and `login_user` no longer entailed on vampi, with the pair-corpus leak rate
    unchanged at 0% on the non-VAmPI pairs -- the check that this suppressed a declaration and not a family.
  - _Requirements: 8.1, 8.2_
  - _Depends: 2.6_

- [x] 2.9 One defect is one finding, however many regions reach it
  - libpng's scan produced 26 entailed findings that are all the identical site,
    `contrib/gregbook/wpng.c:335:main`. Many regions reach one shared sink and each emits its own finding;
    nothing dedupes by site. A contributor would be shown the same defect twenty-six times.
  - Invisible at vampi scale, where regions rarely share a sink, and it appeared the moment task 2.4 let a
    region's question follow the call graph.
  - Dedupe on the reported site, keeping the strongest rung and recording how many regions reached it --
    "reached from 26 entry points" is useful information, twenty-six rows are not.
  - Observable: libpng's entailed count reflects distinct sites; the artifact records both numbers.
  - _Requirements: 5.1, 8.1_
  - _Depends: 2.4_

- [x] 2.11 The suspicion band has to be worth reading
  - libpng's scan produced 198 rows: 26 entailed (all one false positive, since fixed), 113 `c-unsafe-*`
    pattern matches that assert an API is PRESENT rather than misused, 50 overlay-coverage annotations that
    are not findings at all, and 9 model suspicions. Zero validated defects.
  - The rung is honest -- these say "needs review" and mean it -- but a contributor handed 163 rows about a
    library that uses `memcpy` correctly throughout will not read the one that matters. 82 of the 113 are in
    `contrib/`, so task 2.10 removes most of it; what remains needs a policy, not a filter invented here.
  - Observable: a stated rule for what reaches a contributor's report at `suspicion`, and libpng's row count
    under it, measured.
  - _Requirements: 5.1, 5.2_
  - _Depends: 2.10_

- [x] 2.10 Do not spend the scan on example code
  - 22 of libpng's 30 highest-ranked regions are under `contrib/` -- the sample programs shipped with the
    library rather than the library. The budget and the 243s taint query go there first.
  - The rank already comes from the entry-point mapper; what is missing is that a path can be evidence too.
    Vendored, generated, example and test trees are not what a contributor is changing. This is also the
    cheapest available reduction of the 243s.
  - Do not hardcode `contrib/`: derive it, record what was excluded and why, and measure the scan with and
    without so the exclusion is a number rather than a preference.
  - Observable: a recorded before/after on libpng -- regions, query seconds, and entailed sites.
  - _Requirements: 4.2, 8.1_
  - _Depends: 2.2_

- [x] 2.12 A C flow that a bounds check governs is not a finding
  - `c/injection` and `c/memory` carry ZERO sanitizers, so no C flow can ever be discharged. Every
    `argv -> strcpy` entails however carefully it is bounded, which is why libpng reports
    `strcpy(outname+len, ".png")` at wpng.c:374 -- guarded four dozen lines earlier by
    `if ((len = strlen(inname)) > 250)` against a `char[256]`.
  - A sanitizer list will not fix this: the discharge is not a call, it is a GUARD that dominates the sink.
    That abstraction already exists and already works -- it is what `dominance.sc` does for access control --
    and it is wired to one family only. The work is to let a taint family name a guard-shaped discharge and
    route it through the arbiter that can decide one.
  - Observable: wpng.c:374 not entailed, with the pair corpus and both repositories measured either side. Do
    not do this by adding `strlen` to a sanitizer list; that would discharge the unguarded case too.
  - _Requirements: 8.1, 8.2_
  - _Depends: 2.9_

- [ ] 2.13 A destination allocated to size is bounded too
  - 2.12's remainder, and libpng's last entailed finding: `strcpy(output + len, ".icc")` at
    contrib/examples/iccfrompng.c:124, where `output = malloc(len + 5)` and a five-byte copy lands at offset
    `len`. It fits exactly. There is no comparison anywhere, so the bound rule cannot see it -- the
    destination is ALLOCATED to size rather than bounds-checked.
  - Deliberately not done inside 2.12. Both discharge shapes were found on the same repository, and
    extending a rule until one checkout is clean is the overfitting Req 8 exists to prevent. This wants a
    second C checkout with a genuine CWE-121 first, so the change can be measured for what it silences as
    well as what it clears.
  - Observable: iccfrompng.c:124 not entailed, AND a real overflow on another checkout still entailed.
    Without the second half this task should not be closed.
  - _Requirements: 8.1, 8.2_
  - _Depends: 2.12, 5.3_

- [ ] 2.14 Control dependence is not populated, and two arbiters want it
  - Measured, not assumed: **0 of 13,184 calls in the libpng CPG and 0 of 1,152 in the vampi CPG have a
    controlling control structure.** `controlledBy` returns nothing in either, so the PDG's control half is
    simply absent from the graphs we build. The data half is present and load-bearing -- `reachableByFlows`
    is the whole taint arbiter, and `joern-parse` reports `dataflowOss` applied.
  - Everything guard-shaped we do therefore uses CFG dominance (`dominatedBy`) or syntactic conditions
    (`method.controlStructure.condition`) instead. That is why 2.12's first attempt failed: libpng's bound
    reaches its sink through an `error` flag, which is a control-dependence fact and nothing else.
  - Find out whether a CDG overlay can be enabled on `joern-parse` or in the script, what it costs on the
    envelope checkout, and whether it makes the flag-mediated guard decidable. If it cannot be enabled,
    record that -- it bounds what guard reasoning this engine can ever do.
  - Observable: a recorded answer with the build-time and query-time cost, and wpng.c:374 decided or a
    stated reason it cannot be.
  - _Requirements: 4.2, 8.1_
  - _Depends: 2.12_

- [ ] 2.15 A C checkout whose CVE goes through a sink we model
  - libpng cannot demonstrate a C true positive, and pinning an older vulnerable commit would not change
    that. **Every one of the twelve files using `strcpy`/`strcat`/`sprintf`/`gets` is under `contrib/`; the
    library itself uses none of them.** Its overflows are array and pointer arithmetic and `memcpy` sizing,
    and five buffer-overflow fixes checked (`png_set_quantize`, `png_image_finish_read`,
    `png_init_read_transformations`, `png_do_quantize`, `png_write_image_8bit`) touch no modelled sink at
    all.
  - So there are two ways forward and they are different sizes.
  - **Cheap: pin a C project whose CVE genuinely runs through a string function.** That gives the memory
    family its first true positive and tells us whether the family works at all. It does not make libpng
    decidable.
  - **Expensive, and a different engine: model how C actually overflows.** A `memcpy` whose size is
    computed, an index that is not bounded. That is *size arithmetic*, not sink matching -- "can this
    expression exceed this allocation" rather than "does tainted data reach this call". It is a constraint
    problem, which is what SMT is for and what this project deliberately did not adopt: the architecture
    decision was abstract interpretation as arbiter, taken because a model layer can be built from code
    where execution cannot be assumed. That decision was right for the flow families and it does not reach
    this one.
  - The maintainer has attacked libpng this way directly -- SMT to lay out memory, then guiding a fuzzer to
    produce the PNGs that reach it -- which is evidence about the shape of the problem, not a suggestion to
    reimplement it. It says the honest routes to C memory safety are constraint solving or execution, and
    the ladder already has a rung for the second (`execution_confirmed`, built and unreachable per the
    module audit).
  - Observable: a pinned checkout with an in-scope CVE found at a rung, OR a recorded decision that
    `c/memory` is scoped to string-function misuse and makes no claim about arithmetic overflows. Do not
    leave it implying it covers a class it cannot see.
  - _Requirements: 4.1, 4.4_
  - _Depends: 2.12_

- [x] 2.16 Say what `c/memory` actually covers, or retire it
  - Its score so far is zero true positives and every finding a false one: 26 from a substring match, 3 from
    a bound it could not see, 1 from an allocation sized to fit. Each was a real defect in the engine and
    each is now fixed, but the family has never once been right, and 2.15 explains why -- it models string
    functions in a codebase class that overflows through arithmetic.
  - This spec's predecessor threw away parts that did not carry their weight, and the same question applies
    here. The answer may well be "keep it, scoped and labelled" -- `strcpy` misuse is real in plenty of C --
    but it should be a recorded decision with a number behind it, not an assumption.
  - Observable: either a measured true positive on the 2.15 checkout, or the family's declared scope
    narrowed in the facts and the docs so no reader takes a silent C scan for a clean bill of health.
  - **Done 2026-09-09 by the second route: kept, scoped and stated.** `strcpy` misuse is real in plenty of C
    and the family earns its place for that; what it could not do was claim more. Its description said
    "bounds, lifetime, arithmetic", which is exactly what it does not decide -- the description was itself
    the quiet-failure risk. It now names the APIs it models, and a new `limits` field says what it cannot:
    an overflow expressed as an index, a pointer offset, or a memcpy whose size is computed.
  - The report renders it as **What was analysed**, for every family offered to a region whether or not it
    found anything -- a family that ran and reported nothing is the case a reader is most likely to misread.
    The counts are derived from the fact tables the arbiter used, so they cannot drift from what the engine
    really looked for; only the limit sentence is authored.
  - Retiring the family was the alternative and would have been wrong: it would remove the disclosure along
    with the coverage, leaving a C scan silent for a reason nobody could read.
  - _Requirements: 3.1, 8.2_
  - _Depends: 2.15_

- [x] 2.17 The model's own suspicion band is a pattern match with an opinion attached
  - **Req 5.5's other half.** Task 2.11 made pattern matches proportionate and left this untouched, so vampi
    still emits 61 sections for a 520-line application -- 38 of them model suspicions, roughly one per
    fourteen lines of code.
  - The epistemic case for treating them as reasoned claims does not survive inspection. A model suspicion is
    what the enumerator proposed at a site the graph could NOT decide, affirmed by a judge with no coverage
    there. That is a pattern match with an opinion attached, and it is weaker evidence than the obligations
    checker's output, which comes from a structural analysis rather than a guess.
  - So group them by family the way 2.11 groups pattern rules, and keep obligation findings and everything
    at `model_corroborated` or above in full. Expect vampi to fall from 61 sections to roughly 23.
  - Measure both repositories, and measure what it costs: if a real finding only ever appeared at model
    suspicion, this hides it, and that is the number that decides whether the rule is right.
  - _Requirements: 5.1, 5.2, 5.5_
  - _Depends: 2.11_

## Group 3 — Ship it

- [ ] 3.1 Contributor output
  - `model/report.py`: a scan summary — counts per rung, the top findings with witness and `path:line`, and a
    plain statement of what `suspicion` means (the model could not confirm it). Findings to the writable
    output only.
  - Observable: a scan produces a summary readable without opening JSON; every finding shows rung, witness
    and location; nothing is written into the analysed tree.
  - Keeps the disciplines already built into `model/report.py` (Req 8.1, 8.2): per-slice rows with the
    real-world slice deciding, a refused bare aggregate, and the overfitting gap published beside any headline
    — absent rather than zero when a slice is missing.
  - _Requirements: 5.1, 5.2, 5.3, 5.4, 8.1, 8.2_
  - _Depends: 1.3_

- [ ] 3.2 Build and verify the image
  - `docker compose build`, then run a real scan through it and through the shell wrapper. The Dockerfile and
    compose exist and are syntax-valid; **the image has never been built**, so nothing about it is proven.
  - Observable: the image builds; `TARGET=<repo> docker compose run --rm ousast scan /target` produces the
    same findings as a native run; the target mount is read-only; the network is off by default.
  - _Requirements: 6.1, 6.2, 6.3, 6.4, 6.5_
  - _Depends: 3.1_

## Group 4 — Close the deferred decisions

- [ ] 4.1 The memory-family decision
  - Either reach `memory` through an adopted execution tier, or record explicitly that C memory-safety is out
    of scope. 173 of the 176 real-world CVE pairs sit idle behind a stub; the decision gates Req 9.2.
  - Observable: the decision and its reason are recorded where a later reader finds them; if out of scope,
    the corpus says so per slice.
  - _Requirements: 7.1, 7.3_

- [ ] 4.2 Retire `evidence_level`
  - It duplicates `rung` in intent. Retire it, or record why both are kept. Note the legacy value
    `static_corroboration` comes from the flat-IR overlay, which Req 4.4 of the predecessor demotes to the
    suspicion band — so a straight rename would overstate it.
  - Observable: one vocabulary, or a recorded reason for two; SARIF and JSON consumers considered.
  - _Requirements: 7.2, 7.3_

## Group 5 — Grow the corpus

**What group 2 established about each of these**, so none is started on a wrong assumption:

* **PHP/WordPress**: Joern ships `php2cpg`, so the engine can parse it. The blocker is ours --
  `taint_specs(language="php")` returns **zero families**, as do ruby and go. WordPress would parse and
  produce nothing, which is the quiet failure that reads as a clean bill of health. The work is fact tables
  first, corpus second.
* **A known-vulnerable old libpng**: measured and it will not work, for a reason the version cannot fix.
  Every file using `strcpy`/`strcat`/`sprintf`/`gets` is under `contrib/`; the library uses none of them and
  overflows through arithmetic instead. See 2.15 and 2.16.
* **Vibe-code repos**: the best fit available. Python and JavaScript both have full fact tables, the pair
  corpus already carries 70 vibe-py and 17 vfc-js pairs, and vampi -- the one repository where the engine
  finds 3 of 3 -- is exactly this shape. A whole-repository vibe-code checkout is the cheapest next
  measurement that could produce a true positive.

- [ ] 5.1 PHP/WordPress slice
  - **Fact tables landed 2026-09-09** (`benchmarks/measurements/2026-09-09-php-facts.json`). Five families
    derive, and the arbiter decides a real PHP CPG 4 of 4 on a probe: SQL concat entails, its escaped twin
    drops to corroborated, `echo` XSS and `system` command injection entail. `php` added to the region
    model's languages. What remains is below.
  - Plugin and core weaknesses. `php2cpg` needs a PHP interpreter, which the image provides. **Validate on a
    sample that the model can read the pairs before vendoring** — the OWASP harvest found 238 and vendored 40
    for exactly this reason.
  - Observable: a sample measurement precedes vendoring; only categories the model can arbitrate are
    vendored; the slice reports as its own row; every pair states a licence.
  - _Requirements: 9.1, 9.4, 9.5, 9.6, 9.7_
  - _Depends: 3.2_

- [ ] 5.2 More vibe-code pairs, and at least one as a whole repository
  - The pair corpus has 70 vibe-py and 17 vfc-js pairs, all excerpts. Group 2 showed that excerpts cannot
    see the defects a repository shows: nine engine bugs this session, none of them visible to the corpus,
    the gates byte-identical through every fix.
  - So the higher-value half of this task is a **pinned vibe-code repository**, not more pairs. It is the
    cheapest measurement that could produce a second true-positive checkout, because Python and JavaScript
    are the two languages whose fact tables are complete.
  - Observable: a `benchmarks/repos/` recipe for a vibe-code checkout with in-scope known vulnerabilities,
    and a measurement saying which were found at which rung.
  - _Requirements: 9.1, 9.2, 4.1_
  - The slice where the stated audience works, currently 35 pairs. Same read-check discipline.
  - _Requirements: 9.3, 9.4, 9.5, 9.6, 9.7_

- [ ] 5.3 Real-world C library CVEs
  - libpng and the image libraries, OpenSSH, libpam, kernel modules. **Gated on 4.1**: until the memory
    decision closes these would join 173 idle pairs.
  - _Requirements: 9.2, 9.4, 9.5, 9.6_
  - _Depends: 4.1_

- [x] 5.4 WordPress entry points, and the one-verdict-per-region limit
  - Two things stand between the PHP facts and a WordPress result, and the second was found by running the
    first.
  - **Entry points.** WordPress registers handlers with `add_action`, `add_filter`, admin-ajax and REST
    routes. Nothing maps them, so every PHP file becomes one file-level region. The mapper already handles
    registration-based entry points for other frameworks (predecessor task 2.6), so this is a new recogniser
    rather than a new mechanism.
  - **One verdict per region per family.** The taint arbiter returns a single verdict for a region and
    family, so a file-level region reports at most one injection finding however many the file holds: on the
    probe, `system` won on flow length and the SQL injection went unreported. This is the mirror of 2.9 --
    that is many regions collapsing to one site, this is many sites collapsing to one verdict -- and it bites
    hardest where PHP needs it not to.
  - Observable: the probe reports 3 of 3, and a WordPress checkout yields function-scoped regions rather than
    one region per file.
  - _Requirements: 2.1, 8.1, 9.1_
  - _Depends: 5.1_

- [x] 5.5 php2cpg emits a CPG containing one file — NOT A DEFECT, it was the shim
  - **Found by 5.4 and it blocks the WordPress target.** A CPG built over two PHP files contains only one,
    and the survivor is the last alphabetically. Reproduced twice on independent samples; both files parse
    cleanly under `php -l` and under PHP-Parser directly, and `joern-parse` reports success either way.
  - php2cpg logs `Found warning in PHP-Parser JSON output` naming the surviving file, and that warning is
    PHP-Parser's own `====> File X:` banner appearing in what php2cpg expects to be pure JSON. That is the
    thread to pull.
  - Not yet isolated: this machine has no PHP interpreter, so php2cpg was driven through a container shim.
    The banner comes from PHP-Parser rather than from the shim, which makes a shim-only cause unlikely but
    not excluded. **Rerun with the native php-cli in the shipped image first.**
  - A plugin is many files. A scan that silently covers one of them and reports success is exactly the quiet
    failure Req 5.6 was approved for.
  - Observable: a CPG over N PHP files contains N files, or a recorded reason it cannot with the version and
    the reproduction.
  - **Resolved 2026-09-09: there was no defect.** Rerun with a native php-cli (8.3.6, no shim) over the same
    two files and the CPG contains both, all eight methods, and no PHP-Parser banner warning at all. The
    shim ran each `php` invocation in its own container -- needed because this machine has no interpreter --
    and php2cpg drives PHP-Parser per file, so that isolation kept only one file's JSON.
  - **The lesson is worth more than the fix.** Two independent reproductions agreed, and both were measured
    through the same broken instrument. A consistent result is not a correct one when every measurement
    shares an apparatus, which is the same trap as a corpus that cannot see the defect it is scoring.
  - _Requirements: 4.3, 5.6, 9.1_
  - _Depends: 5.4_

- [ ] 5.6 A sanitizer cleanses the family it cleanses, not every family
  - `TaintSpec.sanitizers` is one flat list per language, and its comment states the assumption plainly:
    "a sanitizer that breaks one flow breaks it whatever the sink's family". PHP falsifies it. `esc_html`
    stops XSS and does nothing for SQL injection; `esc_sql` is the reverse; `sanitize_text_field` stops
    neither and is the most-used of the three.
  - **CVE-2023-23488 is the proof.** Its handler calls `sanitize_text_field( $params['code'] )` and then
    concatenates the result into a query. Adding WordPress's sanitizers to the flat list -- the obvious thing
    to do when writing PHP facts -- would make that CVE and its whole class invisible. Task 5.1 therefore
    carries only SQL-specific cleansers, which leaves XSS under-sanitized instead.
  - This is 2.6's finding arriving in the taint family: a discharge counts for the obligation it discharges.
    The dominance arbiter now reads `requires`/kind from the facts; the taint spec has no equivalent.
  - Observable: `esc_html` marks an output_encoding flow sanitized and leaves an injection flow entailed, on
    a pair that carries both.
  - _Requirements: 8.1, 9.1_
  - _Depends: 5.1_

- [x] 5.7 Does the PHP call graph carry a flow through an object? — NOT a call-graph question
  - **The WordPress checkout scans and does not find its CVE.** Both ends are inside the budget --
    `pmpro_rest_api_get_order` at position 290 as a recognised entry point, `getMemberOrderByCode` at 472 --
    and the taint query runs for 23 seconds. So the question is the middle.
  - The flow crosses `new MemberOrder( $code )` into a constructor and then
    `$this->getMemberOrderByCode( $code )`. Both are dynamic in PHP, and whether php2cpg resolves either into
    a CALLEE edge is unverified: two attempts to query the call graph failed on script errors and were
    abandoned rather than guessed at.
  - Answer that first. If the edges exist, the gap is elsewhere -- the source may be `$request->get_params()`
    rather than a superglobal, which `parameter_sources` should cover but has not been checked on this shape.
    If they do not, task 2.4's interprocedural region cannot bridge an object boundary and PHP needs
    something else, which is a finding worth having either way.
  - Observable: a recorded answer naming which edges exist, and either the CVE found or a stated reason it
    cannot be.
  - **Answered 2026-09-09, and it was the wrong question.** The 117k-line pmpro CPG does not LOAD -- import
    throws in a ForkJoinParallelCpgPassWithAccumulator during overlay application -- so every query against
    it returns nothing. Isolated by running the ARBITER against two prebuilt CPGs rather than writing more
    ad-hoc Scala: `get_order_by_code` on the small probe returns 1 `model_entailed` with parameter sources
    and depth 3, while `getMemberOrderByCode` on pmpro, the identical shape, returns 0 under identical
    settings. Same arbiter, same spec, same question; the CPG is the difference.
  - That clears the facts: `$wpdb` sinks work, the parameter-source rule works, and a PHP parameter reaching
    `$wpdb->get_var` through a concat is entailed. Whether php2cpg resolves `new X()` and `$this->method()`
    remains **unmeasured**, because it cannot be measured on a CPG that will not load. Recorded as 5.10.
  - _Requirements: 4.4, 8.1, 9.1_
  - _Depends: 5.1_

- [x] 5.8 WordPress's popular flaw classes, on popular plugins
  - > "in wp focus on some of their popular flaws and plugins. these are the keys to unlock practical
    > software verification."
  - One plugin is a checkout; a class is a claim. WordPress's recurring shapes are narrow and well
    documented, and each maps to a family this engine already has:
    - **Unauthenticated AJAX** — `wp_ajax_nopriv_*` reaching a `$wpdb` query. Declared-public plus injection,
      both of which the mapper and the facts now carry.
    - **Missing capability check** — a handler that acts without `current_user_can` / `check_admin_referer`.
      This is the access_control family, and PHP has NO obligation facts yet, so it cannot be asked at all.
    - **Unescaped output** — a stored option or meta value reaching `echo` without `esc_html`. Blocked on 5.6,
      because the flat sanitizer list cannot say "escapes for HTML but not for SQL".
    - **Arbitrary file operations** — a request value reaching `unlink`/`file_get_contents`. Facts exist.
  - Pick plugins by installed base rather than by convenience, and pin each at a version with a verified
    advisory the way `pmpro.toml` does -- the CVE read out of the code, not out of the advisory text.
  - Observable: a class-by-class table over several plugins, saying for each whether it was found, missed, or
    out of scope. That is the artifact worth teaching from; a single found CVE is not.
  - **Done 2026-09-09.** The table is in `benchmarks/repos/README.md`, "WordPress, class by class". Three
    plugins pinned, each CVE read out of the code, each measured against its own fixed commit:

    | class | plugin, CVE | verdict |
    |---|---|---|
    | unauthenticated injection, sink in the receiving function | `pmpro`, CVE-2023-23488 | **found**, pair separates |
    | arbitrary file operation | `mwwpform`, CVE-2023-6559 | **found**, pair separates |
    | unauthenticated injection across a WordPress hook | `wpstatistics`, CVE-2022-25148 | **missed**, structurally |
    | missing capability check | — | cannot be asked (5.9) |
    | unescaped output | — | cannot be trusted (5.6) |

    Both hits are entailed by the graph alone and both disappear on the fixed side, because both fixes are
    calls the fact tables carry. Precision is not clean and the table says so: PMPro's vulnerable side
    reports 15 entailed, 4 from a named parameter and 11 from the receiver, with one demonstrable false
    positive surviving into 2.9.8.
  - The miss is the useful half. WP Statistics' source and sink are both modelled and the fix is `esc_sql`,
    yet nothing is reported on either side, because the only edge between the two files is
    `add_filter('...', array($this, 'method'))` / `apply_filters('...')` -- both ends naming the callback with
    a **string**. No frontend can draw that edge. Most WordPress plugin data travels this way, which makes it
    the largest structural gap for PHP and not a fact-table problem. The detection strategy for it is
    5.11, which handles it and the `$this` field case with one mechanism.
  - _Requirements: 4.1, 4.4, 9.1_
  - _Depends: 5.7_

- [ ] 5.9 PHP obligation facts, so access control can be asked at all
  - `dominance_specs(language="php")` returns nothing: PHP has no obligated operations and no dischargers, so
    the access-control family is silent on every WordPress scan rather than wrong on it.
  - The vocabulary is small and conventional -- `current_user_can`, `check_admin_referer`, `wp_verify_nonce`,
    `is_user_logged_in` as dischargers; `$wpdb` writes, `update_option`, `wp_delete_post`, `wp_update_user`
    as obligated operations -- and it is the single largest missing WordPress flaw class.
  - Do it after 5.6, so a discharge counts for the obligation it discharges rather than for all of them.
  - Observable: a missing-capability finding on a plugin that has one, and silence on one that checks.
  - _Requirements: 8.1, 9.1_
  - _Depends: 5.6_

- [ ] 5.10 A PHP CPG large enough to matter that actually loads
  - `php2cpg` builds a 4.3MB CPG for a 637-file plugin with no errors, and importing it throws during
    overlay application. Every query then returns nothing.
  - Find the boundary: does it load at 100 files, 300, 600? Is one file responsible, or is it size? Joern's
    own message suggests the frontend for large codebases, which is what the fallback already does, so the
    remaining lever is whether overlays can be applied separately or the tree scoped.
  - Until this is answered, PHP detection is demonstrated only on files small enough to build cleanly, and
    no claim about WordPress can be made either way.
  - Observable: the largest PHP tree that loads and queries, measured, with the failure boundary recorded.
  - **Partly answered 2026-09-09, and it produced the first real CVE.** A two-file slice carrying both ends
    of the CVE -- `classes/class.memberorder.php` and `includes/rest-api.php`, 2885 lines -- loads, queries
    in 122 seconds, and reports **CVE-2023-23488 at class.memberorder.php:936:getMemberOrderByCode**, the
    exact verified line. 16 entailed injection findings, and the file holds 26 `$wpdb` query calls of which
    **zero** use `->prepare`, so the engine under-reports rather than over-reports. See
    `benchmarks/measurements/2026-09-09-pmpro-cve-found.json`.
  - **Root cause found 2026-09-09, and it was never a scale limit.** `php2cpg` 4.0.623 reads its PHP parser's
    stdout and stderr as one merged stream. The parser writes a `====> File <next>:` banner to stderr the
    moment it starts the next file, while the previous file's multi-megabyte JSON is still draining from a
    block-buffered stdout; the banner lands inside the JSON, ujson reports `expected json value got "="`, and
    that file is dropped. Reproducible in three commands:

        class.memberorder.php alone (1834 lines)  ->  142KB CPG, no failures
        the same file + a two-line file           ->  5.7KB CPG, BOTH dropped, exit status 0

    One oversized file empties the whole graph, and `joern-parse` propagates none of the warnings -- thirteen
    lines of output, exit 0, "Successfully wrote graph". It is also a **race**, not a threshold: five builds
    of the same two-file input gave three graphs and two empty ones.
  - Two things follow. The engine now says so (`cpg_empty`, from a census carried on the batched query; see
    `cpg/backend.py`), which is what turned this from a clean bill of health into a diagnosis. And the
    mitigation is per-file, not per-repository: `--exclude` the file whose dump is oversized and the rest of
    the tree builds, so the coverage disclosure should name the excluded files rather than the build failing.
  - Still open: wiring that exclusion loop, the 637-file build with it in place, and whether the REST handler
    two calls away can reach the sink -- the slice found it through a same-function flow, not across the
    object.
  - _Requirements: 4.2, 4.3, 9.1_
  - _Depends: 5.7_

- [ ] 5.11 Two-stage taint with a link table — the detection strategy for both structural misses
  - "Structurally impossible" is a verdict, not a plan, and both PHP structural misses turn out to be the
    SAME shape: two halves of a path, joined by a key that is a literal in the source text.

    ```
    hook:   $_REQUEST -> ... -> return of set_current_page          [half 1]
            key: 'wp_statistics_current_page'   literal at both ends
            return of apply_filters(key) -> ... -> $wpdb->get_row   [half 2]

    field:  $_POST -> ... -> assignment to $this->attachments       [half 1]
            key: attachments                    a field name at both ends
            read of $this->attachments -> ... -> unlink             [half 2]
    ```

    Neither half is missing from the graph. Only the join is. So this is not a request to make a CPG
    frontend draw an edge it cannot draw; it is a second question asked with the query we already have.
  - **Stage 1 -- summaries.** The existing taint question, pointed at a synthetic endpoint instead of a
    modelled sink: does untrusted data reach the RETURN of a registered callback, or an ASSIGNMENT to
    `$this->F`? One extra request per endpoint, on the batch that already runs.
  - **The link table.** Built by reading literals, never by inference: every
    `add_action`/`add_filter('H', callable)` against every `apply_filters`/`do_action('H', ...)`; every
    `$this->F =` against every read of `$this->F` in the same class. The mapper already parses the first of
    those for entry points.
  - **Stage 2 -- the second half.** Again the existing query: does the `apply_filters` return, or the field
    read, reach a modelled sink?
  - **Join on the key**, and let the RUNG carry the join's uncertainty, which is what keeps this honest:
    - exactly one callback registered for the hook, string literal at both ends -> `model_entailed`;
    - several callbacks, or a computed hook name (`"save_post_" . $type`) -> `model_corroborated`, because
      the join is a match rather than a resolution, and the witness must say which.
    Refuse absolutely the approximation "any hook may reach any handler": that is a complete graph over the
    plugin and would entail everything.
  - Costs no new dependency, no CPG mutation and no IR. Both stages ride the batch that already runs, which
    is the whole reason to express this as a query-level join rather than a graph rewrite.
  - **The two compose into a precision win already measured and refused.** With the field half working,
    `_delete_files()` is reached through `$this->attachments` rather than through `$this` being tainted
    wholesale -- so the receiver can then be dropped from parameter sources, taking PMPro's 11
    receiver-sourced findings with it. The fix rejected in 5.8 becomes available once the mechanism under it
    is right, and 5.8's numbers are the before-side of that measurement.
  - Observable, and both are already-pinned pairs so the numbers move or they do not:
    - CVE-2022-25148 entailed on `wpstatistics`'s vulnerable side, absent on its fixed side;
    - CVE-2023-6559 still entailed on `mwwpform` WITH the receiver excluded, and PMPro's receiver-sourced
      count down from 11 to 0 with its CVE still found.
  - Order: the field half first. It is the smaller link table, it has a pinned pair of its own, and it is
    what unlocks the receiver change; the hook half then reuses the same two-stage machinery.
  - _Requirements: 4.4, 6.1, 8.1, 9.1_
  - _Depends: 5.8_

## Group 6 — Regression baselines

- [ ] 6.1 Repository baseline and delta
  - A committed baseline per pinned checkout; a delta report on fact-table or query changes showing findings
    gained, lost and rung movements. An unexplained loss of a previously-entailed finding is a regression to
    investigate, not a number to accept. The baseline records the **engine version**, because a CPG engine
    change moves every verdict.
  - _Requirements: 10.1, 10.2, 10.3, 10.4_
  - _Depends: 2.2_

## Task-plan review notes

- Group 1 must land and pass review before group 2: measuring an unwired pipeline is what produced a
  session's worth of harness-only numbers.
- Task 1.4 was added after 1.3 was wired, when a ten-line scan took three minutes. It belongs in group 1
  because group 1's promise is a working scan, and a scan that cannot finish on a real repository is not one.
  Finding it here rather than in 2.2 is the argument for wiring before measuring.
- **Task 2.2 is a go/no-go.** If one CPG per repository is infeasible, stop and redesign the region/budget
  model rather than building groups 3–6 on an assumption.
- Group 5 is deliberately last. The corpus is not the binding constraint today — reachability is — and 198 of
  238 OWASP pairs were left unvendored precisely because volume without readability makes every number worse.

---

## Lifted out of this spec (2026-09-09)

Two groups drafted here -- a counter-example ledger, and per-repository evolutionary prompting so developers
can commit dismissals and evolve the harness -- were appended directly to this file without passing
requirements or design. That was a workflow error and they are a separate feature, not a refinement of scan
integration. They now live in `.kiro/specs/finding-feedback-loop/`, at brief, unapproved.

Three requirements amendments this group argues for are drafted at the end of `requirements.md`, also
unapproved: what a report may repeat, a family stating a class it cannot decide, and Req 4.1 requiring a
checkout that can actually demonstrate detection.