- The parser of `git grep`'s output uses `bufio.Scanner`, which is a good
choice overall, however it does have a limit that's usually not noticed,
it will not read more than `64 * 1024` bytes at once which can be hit in
practical scenarios.
- Use `bufio.Reader` instead which doesn't have this limitation, but is
a bit harder to work with as it's a more lower level primitive.
- Adds unit test.
- Resolves https://codeberg.org/forgejo/forgejo/issues/3149
(cherry picked from commit 668709a33f)
By using git's ability, end users (especially small instance users) do
not need to enable the indexer, they could also benefit from the code
searching feature.
Fix#29996
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Co-authored-by: silverwind <me@silverwind.io>
