Read the argument count off the code object in weak() - #195
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weak() built an inspect.Signature just to count a bound method's parameters, which costs ~7us and runs on every Watcher/watch() creation with a bound-method fn or callback. For a plain function whose parameters are all regular positional ones the same count can be read straight off the code object, ~100x cheaper. Anything the code object can't describe the same way (wrapped/decorated functions, *args/**kwargs, keyword-only parameters) still falls back to inspect.signature, preserving the previous behavior; the new tests cover a decorated bound-method callback and a *args callback. Measured: watch() with a bound-method fn and callback went from 32.9us to 12.1us. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01UyALuqgF1ZZ3Lj88FzwGVc
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First stable release. Since v0.19.0, observ has had a broad performance overhaul, gained full type-hint coverage and a new trigger_ref API, and picked up a documentation site. New features - trigger_ref(): force-notify the watchers of a proxy, mirroring Vue's triggerRef (#188, closes #123). - Fully typed: modern type hints throughout, a py.typed marker, and ty type-checking enforced in CI (#185, #184, closes #114). Performance - Reworked deep-watch traversal: plain leaf values are filtered out of the traverse stack at push time and raw targets are traversed directly. Traversing large flat/shallow structures is up to ~85% faster (#190). - Lower per-operation trap overhead and proxies constructed with positional flags: reactive reads/writes and proxy creation are ~35-50% faster (#192, #193). - proxy_db lifetimes are managed by reference counting instead of a gc hook, eliminating reference cycles and making cleanup deterministic (#177). - Scheduler and dependency-bookkeeping micro-optimizations: in-place bisect insertion (#191), single-read/write flush counting (#196), a set difference in cleanup_deps (#194), and reading the arg count off the code object in weak() (#195). Correctness - Guarantees, with tests, that observ creates no reference cycles (#189). Documentation - New MkDocs site published to GitHub Pages (#176), with an Internals section (#179) and a rewritten README (#180). Tooling - Modernized CI workflows (#182) and a more robust benchmark guard (#181, #187).
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What
weak()built aninspect.Signaturejust to count a bound method's parameters. That costs ~7µs and runs on everyWatcher/watch()creation that has a bound-method fn or callback. For a plain function whose parameters are all regular positional ones, the same count can be read straight off the code object (__code__.co_argcount), ~100x cheaper.The fast path only applies when it's guaranteed to agree with
inspect.signature: no__wrapped__(decorated methods), no*args/**kwargs(co_flags), no keyword-only parameters. Everything else falls back toinspect.signature, preserving the previous behavior exactly.Tests
Existing tests already cover 1/2/3-argument bound-method callbacks and the too-many-arguments error. New tests in
tests/test_references.pycover the fallback path:functools.wraps-decorated bound-method callback (argument count resolved through the wrapper),*argsbound-method callback (counts as a singlenewargument, asinspect.signaturereports it).Measurements
watch()with a bound-method fn and a bound-method callback: 32.9µs → 12.1µs per creation (20k reps, this machine).Verification
pytest tests: 152 passed (2 new tests)ruff checkandty check: clean🤖 Generated with Claude Code
https://claude.ai/code/session_01UyALuqgF1ZZ3Lj88FzwGVc
Generated by Claude Code