v0.8.0 docs-fidelity finding #1. `pull.py` defined `_EXIT_USAGE=64` and
docs/pull.sh-header promised "64 = usage", but argparse's default
`error()` hard-exits `2` — colliding with `_EXIT_ABORT` (honest gate
hard-stop). A typo and a legitimate gate-block were indistinguishable to
callers/automation (both `2`).
Fix: a contained `_UsageExit64Parser(argparse.ArgumentParser)` overriding
`error()` to exit `_EXIT_USAGE` (64). `--help` is unaffected (goes through
`exit()`, still 0). Verified: no-args / missing-required / unknown-flag
-> 64; --help -> 0; honest hard-stop -> 2 (distinct again); full v0.8.0
suite + kv-calc 22/22 zero regression. Regression-locked by a new
CLI-contract block in test-pull.sh (the pure truth-table can't cover the
argv/exit boundary). docs/PULL.md exit-code table updated to the fixed
contract, with a note that the v0.8.0 *tag* still exits 2 (this lands on
master post-v0.8.0, ships with the next release — not a separate patch
tag, per the maintainer call).
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
