facet-rs / facet / 19946522664

58%

push

github

fix(facet-reflect): fix UB in `Peek::as_str()` for bare `str` types

Fixes #1082.

The `as_str()` method was using `get::<&str>()` for bare `str` shapes,
which caused UB when the str data was empty (reading 16 bytes from a
0-byte allocation).

The fix distinguishes between bare `str` and `&str`:
- For bare `str`: use `get::<str>()` which creates a reference to the
  str bytes pointed to by the wide pointer
- For `&str`: fall through to the existing pointer handler which
  correctly uses `get::<&str>()` to read the fat pointer from memory

This also improves string equality comparison in facet-diff, which
now correctly identifies equal string fields as unchanged.

16 of 16 new or added lines in 1 file covered. (100.0%)

22820 of 39490 relevant lines covered (57.79%)

502.39 hits per line