[NopeCharon]

What and why

PATCH_FORMAT_ARGS keeps the user's diff configuration out of the patches parse_unified_diff reads, but diff.submodule still changed them when a submodule pointer moved (details in #287):

• diff.submodule=log adds Submodule <path> a..b: and > subject lines. The parser appended each > ... line as context to the previous file's last hunk.
• diff.submodule=diff emits the submodule's own file changes, which the canvas listed as attempt changes next to a hunk-less submodule entry.

This PR adds --submodule=short, Git's default, to PATCH_FORMAT_ARGS, so the submodule path shows its Subproject commit hunk regardless of configuration. Like the other options there, it overrides the setting for one command only. It applies to the committed and working-tree attempt patches and to collect_diff's patch.

Fixes #287

Linked Issue for product-semantic or public-contract changes: none (routine fix)

Change class

• Routine fix, documentation, test, maintenance, or presentation-only UI
• Product-semantic or public-contract change discussed in the linked Issue
• Isolated, default-off experiment

Owning layer: server/local_git.py, the Host helper that runs Git for machine consumers (PATCH_FORMAT_ARGS), used by server/work_artifact_registry.py for attempt patches.

User-visible effect, or none: for users with diff.submodule=log or diff, the attempt diff canvas no longer shows commit subjects as file content or submodule-internal files as attempt changes.

Compatibility or migration impact, or none: none. Patches persisted by earlier attempts are not rewritten.

Evidence

Commands and manual journeys run:

• python -m pytest -q tests/test_local_git_provider_diff.py tests/test_work_artifact_registry.py tests/test_unified_diff_canvas.py tests/test_work_export_integration.py: 63 passed (Linux, Python 3.12, uv sync --locked --extra dev, Git 2.43).

• The new test test_attempt_patch_ignores_user_submodule_diff_format (parametrized for log and diff; it finalizes an attempt that moves a real submodule and edits a file) fails on main and passes with this change.

• python tests/test_work_artifact_registry.py: passed.

• ruff check server tests/test_work_artifact_registry.py and git diff --check: passed.

• pytest tests -k "diff or canvas or artifact": 182 passed, 18 skipped. The 6 failures are test_auip_artifact_style.py::test_real_entry_css_delivery_and_advisory_boundaries, which fails the same way on unmodified main in this environment.

• Compared real git diff output for diff.submodule=short/log/diff (Git 2.54); --submodule=short produces the short output under all three settings.

• Relevant Python tests pass

• CPU/model-less baseline remains supported

• Electron npm run build passes when Electron code changed

• Dependency audit passes when dependencies changed

• Before/after screenshots are attached for visible UI changes

• Documentation/examples are updated for changed settings or contracts

Final check

• This PR addresses one coherent problem without unrelated cleanup
• It does not add a speculative API, fallback, or compatibility path
• No secrets, local state, model weights, voice material, or restricted assets are included
• Third-party notices and provenance are preserved

[Lucas1479]

Thank you for the focused submodule-format fix and real-submodule regression coverage. I independently verified log and diff settings through provider.diff and both committed and working-tree attempt patches: the canvas consistently shows the submodule gitlink rather than commit prose or inner files. All 63 relevant Windows tests and all 15 hosted checks pass on this head. The fix belongs in the shared Host patch-format arguments and is ready to merge.