Annotated metadata

[Timbers-Me-Shiver]

Summary

• Interpret typing.Annotated metadata as CrossHair conditions:
  • parameters -> preconditions
  • returns -> postconditions (via return)
  • class attributes -> invariants on self.
• Support annotated_types metadata (Gt / Ge / Lt / Le / MultipleOf / MinLen / MaxLen / Predicate)
  including grouped metadata (Interval / Len).
• Accept custom metadata via is_valid() or any 1‑arg callable.
• Add tests and include annotated-types in dev extras.

Notes

• Avoids typing.get_type_hints() to stay safe under tracing.

Tests

• PRE_COMMIT_HOME=.pre-commit-cache PATH="$(pwd)/.venv/bin:$PATH" ./.venv/bin/pre-commit run --all-files
• PYTHONHASHSEED=0 ./.venv/bin/python -m pytest crosshair/condition_parser_test.py -q

---

Issue #201 comment

I’ve prepared a PR that adds typing.Annotated metadata support to CrossHair.
It treats Annotated metadata as contracts (params -> preconditions, returns ->
postconditions, class attributes -> invariants), supports annotated_types
metadata (Gt / Ge / Lt / Le / MultipleOf / MinLen / MaxLen / Predicate + Interval / Len via
GroupedMetadata), and accepts custom metadata via is_valid() or 1‑arg callables.

Tests:

• PRE_COMMIT_HOME=.pre-commit-cache PATH="$(pwd)/.venv/bin:$PATH" ./.venv/bin/pre-commit run --all-files
• PYTHONHASHSEED=0 ./.venv/bin/python -m pytest crosshair/condition_parser_test.py -q

[Timbers-Me-Shiver]

Separate to above, noted the following failures during test suite run:

Tests run:

• PRE_COMMIT_HOME=.pre-commit-cache PATH="$(pwd)/.venv/bin:$PATH" ./.venv/bin/pre-commit run --all-files
• PYTHONHASHSEED=0 PATH="$(pwd)/.venv/bin:$PATH" ./.venv/bin/python -m pytest crosshair/condition_parser_test.py -q
• env PYTHONHASHSEED=0 PATH="$(pwd)/.venv/bin:$PATH" ./.venv/bin/python -m pytest -n auto --dist worksteal (fails)

Full suite failures (no watcher changes in this PR):

• crosshair/watcher_test.py::test_added_file_to_empty_dir (assert len(results) == 1)
• crosshair/watcher_test.py::test_auditwall_unblock[--unblock=subprocess.Popen:echo-MessageType.CONFIRMED]
• crosshair/watcher_test.py::test_auditwall_unblock[--unblock=subprocess.Popen:xyz-MessageType.EXEC_ERR]

Summary: 3 failed, 11919 passed, 5 skipped, 3 xfailed.

[pschanely]

Thank you SO MUCH for doing this! (and for your patience with my slow response) I've got just a few minor comments below.

Oh also, feel free to add yourself to the contributors list in doc/source/contributing.rst and link it to whatever you like!

[pschanely]

I wouldn't have thought that tracing should be on when we're extracting conditions. (and if it breaks under tracing, that's also a bug I'd love to file)
Do you remember under what circumstances you saw an error?

[pschanely]

typing_extensions is an official dependency, so we don't need to guard the import (or handle None cases below)

[pschanely]

In an ideal world, we'd find the line number of the annotation, in case the signature extends over multiple lines. Unfortunately, I think that's going to be pretty annoying, so maybe we call this close enough!