search_code's scoped grep writes an "<root>/<file>" filelist and pipes it to
xargs. With a newline-separated filelist + plain `xargs`, a space anywhere in
the absolute path splits one file into several bogus arguments, so grep finds
nothing and scoped search returns 0 matches for any repo indexed under a path
containing a space (#687).
Fix: write NUL-separated records and consume them with `xargs -0`, so each path
stays a single argument regardless of spaces. On Windows the scoped path uses
PowerShell `Get-Content | Select-String -LiteralPath`, which reads line-by-line
and already handles spaces, so the filelist keeps newline separators there.
write_scoped_filelist writes each record piece-by-piece with fwrite/fputc (no
fixed-size stack buffer), so arbitrarily long absolute paths cannot overflow.
Reproduce-first: search_code_scoped_path_with_spaces_issue687 indexes a repo
rooted at "<tmp>/my project" and asserts total_grep_matches > 0 (RED on the old
newline + plain-xargs code -> 0 matches; GREEN after). Full suite green.
Distilled from #693 (thanks @lg320531124). Keeps that PR's correct NUL/xargs-0
idea and its Windows newline branch, but replaces its char buf[2048] + unbounded
memcpy (a stack buffer overflow reachable via long indexed paths, PATH_MAX 4096)
with the direct piece-by-piece write, and adds the reproduce-first guard it
lacked.
Closes#687
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
Co-Authored-By: lg320531124 <lg320531124@users.noreply.github.com>
