Incorrect findings reported - PEP758

[ebarti]

This is a classic from all SOTA providers. Without guidance, they will report that a Python project whose minimum version is 3.14 has "invalid Python".

The three exception handlers use Python 2-style multi-exception syntax. Under the project's Python 3 runtime this raises SyntaxError during import, so the prompt/context attribution module and every module importing it fail before tests can execute.

Obviously not true: https://peps.python.org/pep-0758/

[clawsweeper]

Codex review: keeping this open for maintainer follow-up; there is still a little grit to resolve.

Latest ClawSweeper review: 2026-05-22 23:07 UTC / May 22, 2026, 7:07 PM ET.

Workflow note: Future ClawSweeper reviews update this same comment in place.

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Summary
Keep open. The reporter added a concrete CLI reproduction showing Clawpatch reports valid Python 3.14 PEP 758 exception syntax as invalid Python 3 syntax, and current main still has no target-Python-version metadata flow or prompt guard that would prevent this false positive.

Reproducibility: yes. The reporter provided a minimal project and actual clawpatch output, and source inspection shows the current mapper/prompt path lacks the Python 3.14 metadata needed to prevent the false positive; I did not rerun the provider in this read-only review.

Next step
This is a narrow false-positive repair with a concrete reproduction, clear likely files, and no product decision needed.

Review details

Best possible solution:

Add version-aware Python context and review guidance so Clawpatch treats PEP 758 syntax as valid for Python 3.14+ while still flagging it for older target versions, with focused regression coverage.

Do we have a high-confidence way to reproduce the issue?

Yes. The reporter provided a minimal project and actual clawpatch output, and source inspection shows the current mapper/prompt path lacks the Python 3.14 metadata needed to prevent the false positive; I did not rerun the provider in this read-only review.

Is this the best way to solve the issue?

No patch is proposed. The narrow maintainable fix is to surface Python target-version evidence and explicitly cover PEP 758 in mapper or prompt context rather than relying on users to add custom provider guidance.

Label changes:

• add issue-rating: 🦞 diamond lobster: Current issue advisory state selects this label.
• add clawsweeper:source-repro: Current issue advisory state selects this label.
• add clawsweeper:queueable-fix: Current issue advisory state selects this label.
• add clawsweeper:fix-shape-clear: Current issue advisory state selects this label.
• remove issue-rating: 🐚 platinum hermit: Current issue advisory state no longer selects this label.
• remove clawsweeper:needs-live-repro: Current issue advisory state no longer selects this label.

Label justifications:

• P2: This is a concrete false-positive review bug with a minimal reproduction and limited blast radius to Python projects using version-specific syntax.

Acceptance criteria:

• pnpm test src/prompt.test.ts src/mapper.test.ts
• pnpm typecheck
• pnpm lint
• pnpm test
• pnpm build

What I checked:

• Issue reproduction: The reporter provided a minimal project with .python-version set to 3.14 and except TypeError, ValueError: in main.py, then showed clawpatch init && clawpatch map && clawpatch review producing a high-confidence finding that calls the handler Python 2 comma syntax invalid under Python 3.
• PEP 758 syntax source: The official PEP 758 page is Final for Python 3.14 and allows unparenthesized except and except* exception lists when not using an as clause. (peps.python.org)
• Current prompt lacks target-version syntax guidance: The default review prompt emphasizes included files, tests, and avoiding speculative findings, but it does not tell providers to compare Python syntax against the configured target runtime before flagging parse errors. (src/prompt.ts:209, 857d854ac8d0)
• Python mapper omits runtime metadata from source context: The Python mapper creates source-root features and attaches associated tests as context, but the Python source feature path does not include .python-version, pyproject.toml requires-python, or equivalent target-version metadata. (src/mappers/python.ts:153, 857d854ac8d0)
• Project model has no Python target-version field: ProjectRecord.detected carries languages, frameworks, package managers, and commands, but no per-language runtime target version that the prompt or mappers can consistently surface. (src/types.ts:110, 857d854ac8d0)
• No existing PEP 758 handling found: A repository search found no references to PEP 758, Python 3.14 syntax, .python-version, or version-specific multi-exception guidance in source, tests, or docs. (857d854ac8d0)

Likely related people:

• Peter Steinberger: Blame and release-history checks point the current prompt, Python mapper, and project-record shape to the v0.4.0-era implementation authored by Peter Steinberger, which is the central area needing a version-aware prompt or mapper repair. (role: feature-history owner; confidence: medium; commits: cdd58ac59213; files: src/prompt.ts, src/mappers/python.ts, src/types.ts)

Codex review notes: model gpt-5.5, reasoning high; reviewed against 857d854ac8d0.

[ebarti]

Reproduce with:

❯ ls -la
total 40
drwxr-xr-x  11 eloibarti  staff   352 May 22 22:57 .
drwxr-xr-x@ 74 eloibarti  staff  2368 May 22 22:50 ..
drwxr-xr-x   9 eloibarti  staff   288 May 22 22:57 .git
-rw-r--r--   1 eloibarti  staff   109 May 22 22:51 .gitignore
-rw-r--r--   1 eloibarti  staff     5 May 22 22:51 .python-version
drwxr-xr-x   8 eloibarti  staff   256 May 22 22:55 .venv
-rw-r--r--   1 eloibarti  staff     0 May 22 22:51 README.md
-rw-r--r--   1 eloibarti  staff   219 May 22 22:56 main.py
-rw-r--r--   1 eloibarti  staff   165 May 22 22:51 pyproject.toml
-rw-r--r--   1 eloibarti  staff   223 May 22 22:55 uv.lock
❯ cat main.py
def main(x):
    try:
        number = float(x)
    except TypeError, ValueError:
        return 0
    if number.is_integer():
        return int(number)
    return number

if __name__ == "__main__":
    print(main(3))
❯ cat .python-version
3.14

Yields:

❯ clawpatch init && clawpatch map && clawpatch review
created: true
next: clawpatch map
clawpatch map start source=heuristic existing=0 dryRun=false
clawpatch map mapper-start mapper=node
clawpatch map mapper-start mapper=next
clawpatch map mapper-start mapper=react
clawpatch map mapper-start mapper=node-routes
clawpatch map mapper-start mapper=go
clawpatch map mapper-start mapper=python
clawpatch map mapper-start mapper=ruby
clawpatch map mapper-start mapper=elixir
clawpatch map mapper-start mapper=rust
clawpatch map mapper-start mapper=dotnet
clawpatch map mapper-start mapper=c-cpp
clawpatch map mapper-start mapper=swift
clawpatch map mapper-start mapper=apple
clawpatch map mapper-start mapper=gradle
clawpatch map mapper-start mapper=maven
clawpatch map mapper-start mapper=laravel
clawpatch map mapper-start mapper=config
clawpatch map mapper-done mapper=node seeds=0 elapsed=0s
clawpatch map mapper-done mapper=node-routes seeds=0 elapsed=0s
clawpatch map mapper-done mapper=next seeds=0 elapsed=0s
clawpatch map mapper-done mapper=go seeds=0 elapsed=0s
clawpatch map mapper-done mapper=elixir seeds=0 elapsed=0s
clawpatch map mapper-done mapper=rust seeds=0 elapsed=0s
clawpatch map mapper-done mapper=laravel seeds=0 elapsed=0s
clawpatch map mapper-done mapper=swift seeds=0 elapsed=0s
clawpatch map mapper-done mapper=maven seeds=0 elapsed=0s
clawpatch map mapper-done mapper=apple seeds=0 elapsed=0s
clawpatch map mapper-done mapper=c-cpp seeds=0 elapsed=0s
clawpatch map mapper-done mapper=dotnet seeds=0 elapsed=0s
clawpatch map mapper-done mapper=gradle seeds=0 elapsed=0s
clawpatch map mapper-done mapper=ruby seeds=0 elapsed=0s
clawpatch map mapper-done mapper=config seeds=0 elapsed=0s
clawpatch map mapper-done mapper=react seeds=0 elapsed=0s
clawpatch map mapper-done mapper=python seeds=2 elapsed=0s
clawpatch map heuristic-done features=2 new=2 changed=0 stale=0
clawpatch map inventory-start
clawpatch map inventory-done files=6 sourceFiles=1 ownedSourceFiles=1 weak=false elapsed=0s
clawpatch map agent-skip reason=heuristic
clawpatch map write-start features=2
clawpatch map done features=2 usedAgent=false elapsed=0s
features: 2
new: 2
changed: 0
stale: 0
source: heuristic
usedAgent: false
reason: heuristic mapper selected
next: clawpatch review --limit 3
clawpatch review start run=20260522T205725-e326ff features=1 jobs=1
clawpatch review feature-start index=1 total=1 feature=feat_library_25faef2bc4 title=Python source root
clawpatch review feature-done index=1 total=1 feature=feat_library_25faef2bc4 findings=1 elapsed=18s
clawpatch review done run=20260522T205725-e326ff reviewed=1 findings=1
run: 20260522T205725-e326ff
reviewed: 1
findings: 1
jobs: 1
report: /Users/eloibarti/Github/clawsweep-reproduce/.clawpatch/reports/20260522T205725-e326ff.md
next: clawpatch fix --finding fnd_sig-feat-library-25faef2bc4-4b26_5ad0bef77f
❯ cat /Users/eloibarti/Github/clawsweep-reproduce/.clawpatch/reports/20260522T205725-e326ff.md
# clawpatch report

findings: 1

## high: Exception handler syntax prevents Python 3 execution

id: fnd_sig-feat-library-25faef2bc4-4b26_5ad0bef77f
category: build-release
confidence: high
triage: risk
status: open
feature: Python source root (feat_library_25faef2bc4)

evidence:
- main.py:1-4 (main)

The exception clause uses Python 2 comma syntax. In Python 3 this file fails to parse before main can be imported or executed, so the only owned source file is unusable. The intended handler should group exception types explicitly.

recommendation:
Replace the handler with `except (TypeError, ValueError):` so the file parses under Python 3 and catches both conversion failure cases.

test analysis:
No tests are included for this feature, and there is no smoke test that imports or executes main.py under the supported Python runtime.

suggested regression test:
Add a test that imports main.py and verifies `main('bad') == 0`, `main(None) == 0`, `main('3') == 3`, and `main('3.5') == 3.5`.

minimum fix scope:
Update the exception clause in main.py and add a focused import/conversion test.