gitreins-guard-tests-lane-wrong-interpreter-false-red
Solution written to ~/SOLUTION-gitreins-wrong-interpreter.md.
I reproduced the root-cause mechanism locally with the available interpreters (no GitReins/terminal-jail repo present in this sandbox):
pytest resolves to the tool venv's older Python → ModuleNotFoundError on a version-gated stdlib import → 1 error during collection..venv/bin first): bare pytest resolves to the repo interpreter → passes..venv/bin/python -m pytest) with the same broken PATH: passes, proving the pin removes PATH dependence.The document contains:
1 error in collection, tomllib on Python 3.10.20.gitreins resolvable also selects the GitReins venv's 3.10 pytest, so the lane graded the interpreter instead of the code; plus the AGENTS.md doc propagation trap..gitreins/config.yaml guards.test_command: .venv/bin/python -m pytest -x --tb=short (durable fix), and the corrected AGENTS.md PATH order $HOME/go/bin:<repo>/.venv/bin:<gitreins-venv>/bin:$PATH with the one-line "why".# Evidence - Problem class: gitreins-guard-tests-lane-wrong-interpreter-false-red - Model: openrouter/deepseek/deepseek-v4.1-flash - Solved: 2026-09-19T01:32:21.380Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "SYMPTOM (GitReins harness): `gitreins guard --full` reported\n`Tier 1 Guards: FAIL \u2717 tests (full) \u2014 1 error in 0.25s` on a tree whose suite is\ngreen (671 passed / 5 skipped) when run with the documented invocation\n`PATH=\"$HOME/go/bin:$HOME/gitreins-poc/.venv/bin:$PATH\" gitreins guard`. The guard\nlog showed:\n\n collected 548 items / 1 error\n ERROR collecting plugin/test_packaging.py\n plugin/test_packaging.py:27: import tomllib\n E ModuleNotFoundError: No module named 'tomllib'\n platform linux -- Python 3.10.20, pytest-9.1.1\n\nROOT CAUSE: the GitReins CLI lives in its own venv, and that venv is Python 3.10\nand ships its own `pytest`. Putting it first on PATH (the standard way to make\n`gitreins` resolvable) also makes `pytest` resolve to the 3.10 interpreter, so the\nguard's tests lane collects the whole tree under 3.10 even though the repository\nrequires 3.11+ (`tomllib` is stdlib from 3.11). The gate is failing on the\nINTERPRETER, not on the code \u2014 and it fails identically on trees whose suite would\npass, i.e. it is a false RED that trains operators to ignore the tests lane.\n\nDIAGNOSIS THAT DISTINGUISHES IT FROM A REAL TEST FAILURE:\n- the failure is a COLLECTION error (`1 error`, not `N failed`), reported before any\n test ran;\n- the pytest header names a different Python than the repo venv (`Python 3.10.20`\n while `.venv/bin/python -V` says 3.11.15);\n- the missing module is a STDLIB module whose availability is version-gated\n (`tomllib` 3.11+, `except*`/`Self`/`StrEnum` are the same class);\n- the same commit passes when the tests lane runs under the repo interpreter.\n\nFIXES (either is sufficient; both together is what we landed):\n1. Pin the tests lane to the repo interpreter in `.gitreins/config.yaml`:\n `guards.test_command: .venv/bin/python -m pytest -x --tb=short`. This makes the\n lane independent of PATH ordering, which is the durable fix \u2014 any other tool\n resolved from PATH (ruff, gitleaks) can still come from wherever it comes from.\n2. Document a PATH order that works: `PATH=\"$HOME/go/bin:<repo>/.venv/bin:<gitreins-venv>/bin:$PATH\"` \u2014\n the repo venv must PRECEDE the GitReins venv, and `gitreins` itself still resolves\n from the later entry. A one-line \"why\" beside it saves the next reader 30 minutes.\n\nVERIFICATION (both directions, same host, same commit):\n- BEFORE: guard log guard-20260919T005837, `Tier 1 Guards: FAIL`, tests lane\n `ModuleNotFoundError: No module named 'tomllib'`, Python 3.10.20.\n- AFTER the config pin, re-running the guard with the OLD (broken) PATH:\n `Tier 1 Guards: PASS (test mode: full, whole tree)` \u2014 secrets/lint/tests/static\n all green, guard log guard-20260919T012604.\n\nRELATED TRAP: if the repo's own docs teach the broken PATH (an AGENTS.md line), the\nfalse RED reproduces for every agent that follows the docs, and it reads as \"the\nrepo's tests are broken\" in every sync/audit report. Both halves have to move: fix\nthe config AND the documented command.\n\nTRANSFERABLE RULE: a quality gate that shells out to a language toolchain must pin\nthe INTERPRETER, not inherit it from PATH. When a CLI tool ships its own venv, the\nPATH that makes the tool resolvable is exactly the PATH that silently changes which\nruntime grades your code.\n", "environment": "Linux; repo requires Python 3.11+ (stdlib tomllib); GitReins CLI installed in its own Python 3.10 venv that also ships pytest", "language": "python", "model": "openrouter/deepseek/deepseek-v4.1-flash", "problem_class": "gitreins-guard-tests-lane-wrong-interpreter-false-red", "provider": "openrouter", "solved_at": "2026-09-19T01:32:21.381Z", "version": ""}Solution written to ~/SOLUTION-gitreins-wrong-interpreter.md.
I reproduced the root-cause mechanism locally with the available interpreters (no GitReins/terminal-jail repo present in this sandbox):
pytest resolves to the tool venv's older Python → ModuleNotFoundError on a version-gated stdlib import → 1 error during collection..venv/bin first): bare pytest resolves to the repo interpreter → passes..venv/bin/python -m pytest) with the same broken PATH: passes, proving the pin removes PATH dependence.The document contains:
1 error in collection, tomllib on Python 3.10.20.gitreins resolvable also selects the GitReins venv's 3.10 pytest, so the lane graded the interpreter instead of the code; plus the AGENTS.md doc propagation trap..gitreins/config.yaml guards.test_command: .venv/bin/python -m pytest -x --tb=short (durable fix), and the corrected AGENTS.md PATH order $HOME/go/bin:<repo>/.venv/bin:<gitreins-venv>/bin:$PATH with the one-line "why".# Evidence - Problem class: gitreins-guard-tests-lane-wrong-interpreter-false-red - Model: openrouter/deepseek/deepseek-v4.1-flash - Solved: 2026-09-19T01:32:21.380Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "SYMPTOM (GitReins harness): `gitreins guard --full` reported\n`Tier 1 Guards: FAIL \u2717 tests (full) \u2014 1 error in 0.25s` on a tree whose suite is\ngreen (671 passed / 5 skipped) when run with the documented invocation\n`PATH=\"$HOME/go/bin:$HOME/gitreins-poc/.venv/bin:$PATH\" gitreins guard`. The guard\nlog showed:\n\n collected 548 items / 1 error\n ERROR collecting plugin/test_packaging.py\n plugin/test_packaging.py:27: import tomllib\n E ModuleNotFoundError: No module named 'tomllib'\n platform linux -- Python 3.10.20, pytest-9.1.1\n\nROOT CAUSE: the GitReins CLI lives in its own venv, and that venv is Python 3.10\nand ships its own `pytest`. Putting it first on PATH (the standard way to make\n`gitreins` resolvable) also makes `pytest` resolve to the 3.10 interpreter, so the\nguard's tests lane collects the whole tree under 3.10 even though the repository\nrequires 3.11+ (`tomllib` is stdlib from 3.11). The gate is failing on the\nINTERPRETER, not on the code \u2014 and it fails identically on trees whose suite would\npass, i.e. it is a false RED that trains operators to ignore the tests lane.\n\nDIAGNOSIS THAT DISTINGUISHES IT FROM A REAL TEST FAILURE:\n- the failure is a COLLECTION error (`1 error`, not `N failed`), reported before any\n test ran;\n- the pytest header names a different Python than the repo venv (`Python 3.10.20`\n while `.venv/bin/python -V` says 3.11.15);\n- the missing module is a STDLIB module whose availability is version-gated\n (`tomllib` 3.11+, `except*`/`Self`/`StrEnum` are the same class);\n- the same commit passes when the tests lane runs under the repo interpreter.\n\nFIXES (either is sufficient; both together is what we landed):\n1. Pin the tests lane to the repo interpreter in `.gitreins/config.yaml`:\n `guards.test_command: .venv/bin/python -m pytest -x --tb=short`. This makes the\n lane independent of PATH ordering, which is the durable fix \u2014 any other tool\n resolved from PATH (ruff, gitleaks) can still come from wherever it comes from.\n2. Document a PATH order that works: `PATH=\"$HOME/go/bin:<repo>/.venv/bin:<gitreins-venv>/bin:$PATH\"` \u2014\n the repo venv must PRECEDE the GitReins venv, and `gitreins` itself still resolves\n from the later entry. A one-line \"why\" beside it saves the next reader 30 minutes.\n\nVERIFICATION (both directions, same host, same commit):\n- BEFORE: guard log guard-20260919T005837, `Tier 1 Guards: FAIL`, tests lane\n `ModuleNotFoundError: No module named 'tomllib'`, Python 3.10.20.\n- AFTER the config pin, re-running the guard with the OLD (broken) PATH:\n `Tier 1 Guards: PASS (test mode: full, whole tree)` \u2014 secrets/lint/tests/static\n all green, guard log guard-20260919T012604.\n\nRELATED TRAP: if the repo's own docs teach the broken PATH (an AGENTS.md line), the\nfalse RED reproduces for every agent that follows the docs, and it reads as \"the\nrepo's tests are broken\" in every sync/audit report. Both halves have to move: fix\nthe config AND the documented command.\n\nTRANSFERABLE RULE: a quality gate that shells out to a language toolchain must pin\nthe INTERPRETER, not inherit it from PATH. When a CLI tool ships its own venv, the\nPATH that makes the tool resolvable is exactly the PATH that silently changes which\nruntime grades your code.\n", "environment": "Linux; repo requires Python 3.11+ (stdlib tomllib); GitReins CLI installed in its own Python 3.10 venv that also ships pytest", "language": "python", "model": "openrouter/deepseek/deepseek-v4.1-flash", "problem_class": "gitreins-guard-tests-lane-wrong-interpreter-false-red", "provider": "openrouter", "solved_at": "2026-09-19T01:32:21.381Z", "version": ""}