fix: fix indefinite ParaTest hang: stream_set_timeout() does not apply to writes

[albertcht]

Summary

The component test suite hung indefinitely near completion when run through ParaTest (composer test:parallel), surfacing as a WorkerCrashedException for tests/Prompts/LoggerTest.php with Exit Code: -1(Unknown error).

Root cause: Utils::writeAll() relies on stream_set_timeout() to bound how long a write may stall. PHP's stream_set_timeout() only governs reads — it has no effect on writes. On macOS, a blocking fwrite() into a full socket buffer parks in sendto(2) forever: no timeout applies, and PHPUnit's SIGALRM-based time limit cannot interrupt the syscall.

Fix: drive the stream non-blocking and wait for writability with stream_select(), with the timeout passed explicitly by the caller.

This is not a recurrence of #454. That fix (COLUMNS/LINES in phpunit.xml.dist) is still present and still effective; git merge-base --is-ancestor confirms it was already in place when this defect was introduced.

Symptoms

• composer test:parallel hangs permanently at ~99%.
• composer test (plain PHPUnit) reproduces it too — this is not ParaTest-specific.
• The affected test is always tests/Prompts/LoggerTest.php, not a random unrelated test.
• CI is green.
• A stalled worker's native stack:

  zif_fwrite
    <- _php_stream_write
    <- _php_stream_write_buffer
    <- php_sockop_write
    <- __sendto
  

• lsof on the stalled worker shows only a Unix socketpair with both ends open in the same process (fds 10 and 11 pointing at each other) — no reactor, no child process, no network socket.

Root cause

Utils::writeAll() was written to detect a stalled reader like this:

$written = @fwrite($stream, substr($payload, $offset));
// ...
$metadata = stream_get_meta_data($stream);

if ($metadata['timed_out']) {
    throw new RuntimeException('The prompt renderer timed out while receiving output.');
}

On macOS that timed_out branch is unreachable: execution never returns from the fwrite() on the line above.

Verified directly with php -n (no extensions loaded, so this is not Swoole-related):

Operation	macOS	Linux (php:8.4-cli in Docker)
fread + stream_set_timeout(1)	timed_out=true after 1.00s	—
fwrite + stream_set_timeout(1) into a full buffer	blocks forever in sendto(2)	timed_out=true after 1.02s

A Unix socketpair's send buffer is 8192 bytes on this platform, so any payload larger than that stalls once the reader stops draining.

The trigger is LoggerTest::testNoReaderTimesOutAfterOneWindowFollowingAPartialWrite, which creates a socketpair, keeps both ends in the same process, and writes 8 MB. Nothing ever drains the buffer, so the write blocks permanently.

Why CI never caught it

The Linux kernel applies SO_SNDTIMEO to socket writes, so on Linux the timed_out branch really is reached and the test passes. This is a genuine platform behavior difference, not timing jitter — unlike #454, it is fully deterministic on each platform.

Why PHPUnit's 60-second limit did not rescue it

enforceTimeLimit relies on SIGALRM, which cannot be delivered while PHP is blocked inside sendto(2). Attaching a debugger and detaching (delivering SIGSTOP/EINTR) was enough to unblock a stalled worker, which independently confirms the process was parked in an uninterrupted syscall.

When this was introduced

Date	Commit	Change
2026-07-26	(#454 merge)	COLUMNS/LINES pinned in phpunit.xml.dist
2026-08-07 23:52	1b58cf1ec	Added Utils::writeAll() with the timed_out branch
2026-08-07 23:53	e1e5f63ed	Added the four socket-based LoggerTest cases

Before e1e5f63ed, LoggerTest had a single test that never touched a socket, and the old Logger::write() was a bare one-line fwrite() that never exceeded the buffer. Both files have been unchanged since 2026-08-07, so every macOS run since then was affected.

The fix

Utils::writeAll()

Rewritten to bound the wait portably:

• The stream is switched to non-blocking, so fwrite() returns 0 instead of parking when the buffer is full.
• stream_select() waits for writability, bounded by an explicit $timeout parameter (default 10.0 seconds).
• The original blocking mode is restored in a finally block on every exit path.
• Chunks are capped at 64 KiB per attempt. Passing the full remainder to substr() on every iteration made the copy cost quadratic — measured at 0.145s vs 0.002s for a 4 MB payload over 1023 iterations.
• php://memory streams are excluded from the non-blocking path: they always accept a full write, and stream_select() rejects them with ValueError: No stream arrays were passed.

Error classification was also corrected. The previous code consulted feof() whenever a write did not complete, including when fwrite() returned 0. A zero-byte write means "buffer full", never "peer closed", and under Swoole's coroutine hook feof() can report a stale EOF in that state. Closure is now reported only when fwrite() actually returns false.

Logger

Takes a $writeTimeout constructor parameter, defaulting to the new Logger::DEFAULT_WRITE_TIMEOUT_SECONDS (10.0), and forwards it to Utils::writeAll().

Task

Removes three calls that had no effect on writes and threads the timeout through instead:

• stream_set_timeout($this->socket, ...) before constructing the Logger — removed; the value is now a constructor argument.
• stream_set_blocking($socket, true) before the renderer acknowledgement — removed; writeAll() now owns the stream's blocking mode.
• Both remaining Utils::writeAll() call sites now pass LOGGER_WRITE_TIMEOUT_SECONDS explicitly.

This also fixes a production defect. Task::LOGGER_WRITE_TIMEOUT_SECONDS = 10 was inert on macOS: any application whose task renderer child stopped reading would hang the parent process permanently, with no timeout and no way to interrupt it. That path is reached by ordinary Task usage outside a coroutine, not only by tests.

A Swoole coroutine caveat worth recording

UtilsTest runs inside a Swoole coroutine (SWOOLE_HOOK_ALL), and the hook changes socket semantics in ways that are not stable enough to assert on:

• Writes to a closed peer are silently buffered and can succeed indefinitely — 40 consecutive writeAll() calls never reported closure.
• feof() sometimes reports EOF on a freshly created socketpair whose peer is demonstrably still open (is_resource() true, peer readable).
• Whether either occurs depends on how much socket churn preceded the test in the same process.

Attempts to add closed-peer and write-timeout assertions to UtilsTest therefore passed in isolation and failed in suite order. Those assertions live in LoggerTest instead, which sets $runTestsInCoroutine = false for exactly this reason. tests/Prompts/UtilsTest.php is unchanged by this PR.

This is worth knowing before writing any future test that asserts on socket error states inside a coroutine.

Test changes

tests/Prompts/LoggerTest.php only:

• testNoReaderTimesOutAfterOneWindowFollowingAPartialWrite and testProgressingReaderMayExceedTheNoProgressWindow now pass the window as a Logger constructor argument instead of calling the ineffective stream_set_timeout().
• Added testRestoresTheOriginalBlockingModeAfterATimedOutWrite — the stream must not be left non-blocking after a timeout.
• Added testWritesAnEntirePayloadToAnInMemoryStream — covers the php://memory path that cannot use stream_select().

No test was weakened or removed to accommodate the source change.

Validation

Check	Result
tests/Prompts	466 tests, 2051 assertions, all passing
composer test:parallel (--processes=8)	3 consecutive full runs, ~70s each, zero hangs
composer test:testbench	506 tests passing
PHPStan (src/prompts)	No errors
php-cs-fixer	0 of 125 files need fixing

Timing evidence that the timeout is real rather than merely absent:

• testNoReaderTimesOutAfterOneWindowFollowingAPartialWrite completes in 1.005s (previously blocked forever).
• testProgressingReaderMayExceedTheNoProgressWindow still takes 1.518s — a slow but progressing reader is not killed by the timeout.

Before this change the full parallel suite never completed. It now finishes in ~70 seconds.

Summary by CodeRabbit

• Bug Fixes
  • Improved reliability when sending log messages and task updates over slow or blocked connections.
  • Added bounded write handling to prevent stalled operations from waiting indefinitely.
  • Ensured stream behavior is restored after timed-out writes.
  • Improved support for complete writes to in-memory streams.

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📝 Walkthrough

Walkthrough

Changes

The PR adds configurable write timeouts to Logger, implements bounded stream writes in Utils::writeAll, and applies the timeout to Task socket messages and renderer acknowledgements. Tests cover timeout failures, blocking-mode restoration, and complete in-memory writes.

Write timeout flow

Layer / File(s)	Summary
Bounded write engine src/prompts/src/Support/Utils.php	Utils::writeAll writes in capped chunks, waits for writable streams, handles empty payloads and failures, and restores blocking mode.
Logger timeout contract src/prompts/src/Support/Logger.php, tests/Prompts/LoggerTest.php	Logger exposes a 10-second default, accepts a configurable timeout, and passes it to Utils::writeAll. Tests cover timeout configuration, failure handling, blocking-mode restoration, and complete memory-stream writes.
Task write integration src/prompts/src/Task.php	Task uses the shared default and applies the configured timeout to logger, reset-message, and renderer acknowledgement writes.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Merge Risk: 🟡 Moderate · up to f7c41

The write path now restores caller-provided non-blocking streams as blocking, which can unexpectedly change subsequent I/O behavior and introduce hangs for callers relying on non-blocking operation. Merge should wait for this behavior to be corrected or explicitly accepted by the owner.

Sequence Diagram(s)

sequenceDiagram
  participant Task
  participant Logger
  participant UtilsWriteAll
  participant RendererSocket
  Task->>Logger: Construct with write timeout
  Task->>Logger: Write renderer message
  Logger->>UtilsWriteAll: Write payload with timeout
  UtilsWriteAll->>RendererSocket: Write bounded chunks
  UtilsWriteAll-->>Logger: Complete write or timeout failure
  Task->>UtilsWriteAll: Write reset or acknowledgement with timeout

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Possibly related PRs

• hypervel/components#488: Both PRs modify Logger, Utils::writeAll, Task, and LoggerTest for complete, timeout-bounded writes.

Suggested reviewers: binaryfire

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the main change: fixing an indefinite ParaTest hang caused by stream write timeouts not applying.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 1

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Inline comments:
In `@src/prompts/src/Support/Utils.php`:
- Around line 98-100: Update writeAll() to capture
stream_get_meta_data($stream)['blocked'] before changing the stream mode, then
restore blocking mode only if it was originally enabled instead of always
enabling it after a successful change. Add a regression test using a
non-blocking socket and verify it remains non-blocking after writeAll() returns.

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