A .gitignore transparently encrypted in place by corporate DLP / endpoint
software (UTF-16 header + ciphertext), or one containing a pattern the
`ignore` library can't compile to a regex (`\[` -> "Unterminated character
class"), crashed the entire sync/index. The throw is LAZY — it surfaces at
match time (`ig.ignores()`), not `.add()` — so the existing add-time
try/catch never caught it, and the error never named the offending file.
Read .gitignore defensively: skip a file that isn't valid UTF-8 text whole
(NUL byte or fatal UTF-8 decode), drop only the individual uncompilable
patterns from a text one (probe-compile, then per-line fallback), and warn
with the file path. Indexing continues either way. The watcher inherits the
fix via buildDefaultIgnore.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>