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[Server] Fix a flaky timing test and show why a concurrent session writer fails #717

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Merged
chr-hertel merged 2 commits into from
Nov 9, 2026
Merged

[Server] Fix a flaky timing test and show why a concurrent session writer fails #717

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538697f
[Server] Allow for a sleep that ends early in the StatelessResponder …
chr-hertel Nov 9, 2026
b857163
[Server] Show why a concurrent writer fails in the FileSessionStore test
chr-hertel Nov 9, 2026
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17 changes: 15 additions & 2 deletions tests/Unit/Server/Session/FileSessionStoreTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -385,7 +385,12 @@ public function testConcurrentWritesNeverPublishAPartialPayload(): void
// The writers finish in whatever order they like.
ksort($exitCodes);

$this->assertSame([0, 0, 0], $exitCodes, 'The concurrent writers did not all run to completion.');
$errors = '';
foreach (array_keys($writers) as $i) {
$errors .= file_get_contents($this->directory.\DIRECTORY_SEPARATOR.'writer-'.$i.'.err');
}

$this->assertSame([0, 0, 0], $exitCodes, 'The concurrent writers did not all run to completion: '.$errors);

foreach (array_keys($writers) as $i) {
$this->assertSame('', file_get_contents($this->directory.\DIRECTORY_SEPARATOR.'writer-'.$i.'.err'));
Expand All @@ -406,12 +411,20 @@ private function spawnWriter(UuidV4 $id, int $index)

require $argv[1];

$store = new Mcp\Server\Session\FileSessionStore($argv[2]);
// The store logs why a write failed, which ends up in this writer's error file.
$logger = new class extends Psr\Log\AbstractLogger {
public function log($level, $message, array $context = []): void
{
fwrite(\STDERR, $level.': '.$message.' '.json_encode($context).\PHP_EOL);
}
};
$store = new Mcp\Server\Session\FileSessionStore($argv[2], logger: $logger);
$id = Symfony\Component\Uid\Uuid::fromString($argv[3]);
$payload = json_encode(['queue' => array_fill(0, 200, str_repeat('x', 200))]);

for ($i = 0; $i < 200; ++$i) {
if (!$store->write($id, $payload)) {
fwrite(\STDERR, sprintf('Write %d of 200 failed.', $i + 1).\PHP_EOL);
exit(1);
}
}
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3 changes: 2 additions & 1 deletion tests/Unit/Server/Transport/Http/StatelessResponderTest.php
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Expand Up @@ -46,7 +46,8 @@ public function testReadingTheStreamWritesTheFrames(): void
$elapsed = microtime(true) - $start;

$this->assertSame(['data: {"method":"first"}'."\n\n", ': keep-alive'."\n\n", 'data: {"id":1}'."\n\n"], $flushed, 'Each frame is flushed on its own.');
$this->assertGreaterThanOrEqual(0.25, $elapsed, 'The idle turn waits before the next poll.');
// The turn sleeps 250 ms, which Windows can end slightly early.
$this->assertGreaterThanOrEqual(0.2, $elapsed, 'The idle turn waits before the next poll.');
$this->assertLessThan(1.0, $elapsed, 'The idle turn waits once.');
}

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