moonbitlang / core / 6580

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github

Committed by bobzhang

Commit Message

feat(builtin): add clamped_view for FixedArray/ReadOnlyArray

Completes the total view variant across the whole family. `FixedArray` mirrors
`Array::clamped_view` through
`unsafe_cast_fixedarray_to_uninitializedarray`; `ReadOnlyArray` delegates to
`FixedArray::clamped_view` via `unsafe_reinterpret_to_fixed_array()`, the same
way its existing `view` and `get_view` delegate.

Contract is unchanged: both offsets are clamped independently into
`[0, length()]`, an inverted range yields an empty view at the clamped `start`,
and the result aliases the backing storage.

Codex CLI review: "No blocking issues in the uncommitted diff. `ReadOnlyArray`
correctly forwards `start` in both arms. Omitting `end` produces exactly the
same bounds as explicitly passing `length()` [...] Clamping guarantees
`0 <= lo <= len` and `0 <= count <= len - lo`; subtraction cannot overflow."

It also spotted a real gap: with the `end=None` arm exercised only at starts 0,
-5 and 100, a `start * 2` mutation there survived the suite. The added test
"clamped_view with `end` omitted forwards `start` unchanged" compares the
omitted-`end` result against an explicit `end=5` across every start in -1..=6,
including `start_offset()`; that mutation now fails 1 test.

Signed-off-by: Codex CLI <codex@openai.com>
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01F4N5Hc1TYuJW5oRDTY19Wf

Coverage Stats

11 of 11 new or added lines in 2 files covered. (100.0%)

8 existing lines in 1 file now uncovered.

16365 of 18332 relevant lines covered (89.27%)

273908.83 hits per line