A `download_path` naming a FIFO hung the turn outright. The target is
opened write-only, which on POSIX blocks until a reader attaches, so the
`isFile()` refusal sitting behind that open was unreachable — the open
never returned. The path comes from the server, so this needed no planted
file to reach, only a named pipe where a download was aimed. Opening
non-blocking turns a readerless pipe into an immediate refusal and leaves
the existing guard to reject one that has a reader; the flag is inert on
regular files, which is every legitimate target. (The repo already fixed
this shape once, for discovery context-file reads, by stat-gating; the
flag closes the same hole without the stat's TOCTOU window.)
A `pi_grep` that hit the native backend's own match ceiling answered as an
unqualified success. `GrepTool` folds that cap into the flat
`details.truncated` and sets neither `details.truncation` nor
`perFileLimitReached` — the two fields the Pi result reads — so the one
truncation a caller can neither detect nor page around was the one it was
never told about. The flat flag now translates into a `PiTruncation`, and
only once the specific counters came back empty, so a cap that already
reported itself is never restated.
Both regressions are locked: the FIFO test detects a relapse by timing out
rather than by a failed assertion, since a relapse never reaches the
assertion.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014oA3H7aHUL85ydp9PJ3ryF
(cherry picked from commit 20438ff68cf9c8aaaec30703f5b9972c7bda205e)
Diogo Soares Rodrigues
7f97581d0a