Fix GH-10031: [Stream] STREAM_NOTIFY_PROGRESS over HTTP emitted irregularly for last chunk of data

ext/standard/http_fopen_wrapper.c

@@ -955,6 +955,13 @@ static php_stream *php_stream_url_wrap_http_ex(php_stream_wrapper *wrapper,
 		if (transfer_encoding) {
 			php_stream_filter_append(&stream->readfilters, transfer_encoding);
 		}
+
+		/* It's possible that the server already sent in more data than just the headers.
+		 * We account for this by adjusting the progress counter by the difference of
+		 * already read header data and the body. */
+		if (stream->writepos > stream->readpos) {
+			php_stream_notify_progress_increment(context, stream->writepos - stream->readpos, 0);
+		}
 	}
 
 	return stream;

ext/standard/tests/streams/gh10031.phpt

@@ -0,0 +1,52 @@
+--TEST--
+GH-10031 ([Stream] STREAM_NOTIFY_PROGRESS over HTTP emitted irregularly for last chunk of data)
+--SKIPIF--
+<?php
+if (getenv("SKIP_SLOW_TESTS")) die("skip slow test");
+?>
+--INI--
+allow_url_fopen=1
+--CONFLICTS--
+server
+--FILE--
+<?php
+
+$serverCode = <<<'CODE'
+$fsize = 1000;
+$chunksize = 99;
+$chunks = floor($fsize / $chunksize); // 10 chunks * 99 bytes
+$lastchunksize = $fsize - $chunksize * $chunks; // 1 chunk * 10 bytes
+
+header("Content-Length: " . $fsize);
+flush();
+for ($chunk = 1; $chunk <= $chunks; $chunk++) {
+    echo str_repeat('x', $chunksize);
+    @ob_flush();
+    usleep(50 * 1000);
+}
+
+echo str_repeat('x', $lastchunksize);
+CODE;
+
+include __DIR__."/../../../../sapi/cli/tests/php_cli_server.inc";
+php_cli_server_start($serverCode, null, []);
+
+$context = stream_context_create(['http' => ['ignore_errors' => true,]]);
+$lastBytesTransferred = 0;
+stream_context_set_params($context, ['notification' => function ($code, $s, $m, $mc, $bytes_transferred, $bytes_max)
+use (&$lastBytesTransferred) {
+    if ($code === STREAM_NOTIFY_FILE_SIZE_IS) echo "expected filesize=$bytes_max".PHP_EOL;
+    $lastBytesTransferred = $bytes_transferred;
+    @ob_flush();
+}]);
+
+$get = file_get_contents("http://".PHP_CLI_SERVER_ADDRESS, false, $context);
+
+echo "got filesize=" . strlen($get) . PHP_EOL;
+var_dump($lastBytesTransferred);
+
+?>
+--EXPECT--
+expected filesize=1000
+got filesize=1000
+int(1000)