Do not use up retries on requests which timed out during a prompt

Nothing drives the transfers while tick() is blocked, e.g. by a prompt
for credentials, so requests which are still connecting time out with
curl error 28. Since #12662 these are retried, but each retry counts
like any other, so a few prompts can use up all of them, and parallel
requests to a private host which timed out that way abort with
"Invalid credentials" once the first of them got credentials, as
AuthHelper only reuses those for a request which was not retried yet.

tick() now keeps track of how long it was blocked between two ticks,
and a request which spent most of its time in that gap is restarted
without counting towards maxRetries.

Fixes #12402

src/Composer/Util/Http/CurlDownloader.php

@@ -69,6 +69,12 @@ class CurlDownloader
      * @var array<string, array{statusCode: int, announced: bool, until: float}>
      */
     private $retryAfterOrigins = [];
+    /**
+     * When tick() last waited on the transfers, they are not driven again until the next tick(), which a prompt can hold up
+     *
+     * @var float|null
+     */
+    private $lastSelectAt = null;
     /** @var IOInterface */
     private $io;
     /** @var Config */
@@ -397,12 +403,14 @@ class CurlDownloader
             return;
         }
 
+        $blockedFor = null !== $this->lastSelectAt ? microtime(true) - $this->lastSelectAt : 0.0;
         $active = true;
         $this->checkCurlResult(curl_multi_exec($this->multiHandle, $active));
         if (-1 === curl_multi_select($this->multiHandle, $this->getSelectTimeout())) {
             // sleep in case select returns -1 as it can happen on old php versions or some platforms where curl does not manage to do the select
             usleep(150);
         }
+        $this->lastSelectAt = microtime(true);
 
         while ($progress = curl_multi_info_read($this->multiHandle)) {
             $curlHandle = $progress['handle'];
@@ -437,6 +445,18 @@ class CurlDownloader
                     }
                     $progress['error_code'] = $errno;
 
+                    // a request which spent most of its time blocked between two ticks, e.g. by a prompt for credentials, did not time out
+                    // on its own, so it is retried without counting towards maxRetries, see https://github.com/composer/composer/issues/12402
+                    if (
+                        $errno === 28 /* CURLE_OPERATION_TIMEDOUT */
+                        && $blockedFor > $progress['total_time'] / 2
+                        && (!isset($job['options']['http']['method']) || $job['options']['http']['method'] === 'GET')
+                    ) {
+                        $this->io->writeError('Retrying ' . Url::sanitize($job['url']) . ' due to curl error 28 while the download loop was blocked', true, IOInterface::DEBUG);
+                        $this->restartJob($job, $job['url']);
+                        continue;
+                    }
+
                     if (
                         (!isset($job['options']['http']['method']) || $job['options']['http']['method'] === 'GET')
                         && (

tests/Composer/Test/Util/Http/CurlDownloaderTest.php

@@ -200,6 +200,38 @@ class CurlDownloaderTest extends TestCase
         self::assertSame([], $this->readProperty($downloader, 'jobs'), 'a cancelled request must not be sent again');
     }
 
+    public function testTimeoutWhileTheLoopWasBlockedDoesNotUseUpARetry(): void
+    {
+        // the kernel accepts the connection but nothing ever answers, so the request can only time out
+        $server = stream_socket_server('tcp://127.0.0.1:0');
+        self::assertIsResource($server);
+        $address = stream_socket_get_name($server, false);
+        self::assertIsString($address);
+
+        $downloader = $this->createDownloader();
+        $failure = null;
+        // a request which has no retries left, e.g. after timing out during earlier prompts
+        self::callPrivate($downloader, 'initDownload', static function (): void {
+        }, static function (\Exception $e) use (&$failure): void {
+            $failure = $e->getMessage();
+        }, $address, 'http://'.$address.'/packages.json', ['http' => ['timeout' => 1]], null, ['retries' => 3]);
+
+        $downloader->tick();
+        // a prompt for credentials keeps tick() from being called for longer than the request may take
+        usleep(1500000);
+        $downloader->tick();
+
+        self::assertNull($failure);
+        $jobs = $this->readProperty($downloader, 'jobs');
+        self::assertIsArray($jobs);
+        self::assertCount(1, $jobs, 'the request must have been sent again');
+
+        foreach (array_keys($jobs) as $id) {
+            $downloader->abortRequest((int) $id);
+        }
+        fclose($server);
+    }
+
     public function testRetryWaitsForTheLatestRetryAfterOfItsOrigin(): void
     {
         $io = new BufferIO();