php-in-php: VmMemory RSS — remove host getrusage() fallback (#7287)

ext/standard/VmMemory.php

@@ -69,27 +69,24 @@ private static function readEmallocApprox(): int
         return $rss;
     }
 
+    /**
+     * RSS via /proc/self/statm only (issue #7287, #4862).
+     *
+     * JIT/AOT use the same source in MemoryRuntime::__phpc_memory_read_rss_bytes.
+     */
     private static function readRssBytes(): int
     {
-        if ('Linux' === \PHP_OS_FAMILY && is_readable('/proc/self/statm')) {
-            $statm = @file_get_contents('/proc/self/statm');
-            if (false !== $statm && '' !== $statm) {
-                $parts = preg_split('/\s+/', trim($statm));
-                $rssPages = (int) ($parts[1] ?? 0);
-
-                return $rssPages * self::pageSize();
-            }
+        if ('Linux' !== \PHP_OS_FAMILY || !is_readable('/proc/self/statm')) {
+            return 0;
         }
-
-        if (\function_exists('getrusage')) {
-            $ru = getrusage();
-            if (\is_array($ru) && isset($ru['ru_maxrss'])) {
-                // Linux: kilobytes; BSD often bytes — treat as KiB (php-src ZEND_SYS_VMEM).
-                return (int) $ru['ru_maxrss'] * 1024;
-            }
+        $statm = @file_get_contents('/proc/self/statm');
+        if (false === $statm || '' === $statm) {
+            return 0;
         }
+        $parts = preg_split('/\s+/', trim($statm));
+        $rssPages = (int) ($parts[1] ?? 0);
 
-        return 0;
+        return $rssPages * self::pageSize();
     }
 
     private static function pageSize(): int

test/unit/VmMemoryTest.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPCompiler\Test\Unit;
+
+use PHPCompiler\ext\standard\VmMemory;
+use PHPUnit\Framework\TestCase;
+
+/** VmMemory RSS path without host getrusage() delegation (issue #7287, #4862). */
+final class VmMemoryTest extends TestCase
+{
+    public function testSourceDoesNotDelegateToHostGetrusage(): void
+    {
+        $source = (string) file_get_contents(__DIR__.'/../../ext/standard/VmMemory.php');
+        $this->assertDoesNotMatchRegularExpression('/function_exists\\s*\\(\\s*[\'"]getrusage/', $source);
+        $this->assertDoesNotMatchRegularExpression('/\\\\getrusage\\s*\\(/', $source);
+        $this->assertStringContainsString('/proc/self/statm', $source);
+    }
+
+    public function testRealUsageReadsProcStatmOnLinux(): void
+    {
+        if ('Linux' !== \PHP_OS_FAMILY || !is_readable('/proc/self/statm')) {
+            $this->markTestSkipped('Linux /proc/self/statm required for RSS probe');
+        }
+
+        $this->assertGreaterThan(0, VmMemory::getUsage(true));
+    }
+}