[Filesystem] Add $suffix argument to tempnam()

Fixes #33002

Author: jdufresne

CHANGELOG.md

@@ -10,6 +10,7 @@ CHANGELOG
 -----
 
  * support for passing a `null` value to `Filesystem::isAbsolutePath()` is deprecated and will be removed in 5.0
+ * `tempnam()` now accepts a third argument `$suffix`.
 
 4.3.0
 -----

Filesystem.php

@@ -584,15 +584,17 @@ public function isAbsolutePath(string $file)
      *
      * @param string $prefix The prefix of the generated temporary filename
      *                       Note: Windows uses only the first three characters of prefix
+     * @param string $suffix The suffix of the generated temporary filename
      *
      * @return string The new temporary filename (with path), or throw an exception on failure
      */
-    public function tempnam(string $dir, string $prefix)
+    public function tempnam(string $dir, string $prefix/*, string $suffix = ''*/)
     {
+        $suffix = \func_num_args() > 2 ? func_get_arg(2) : '';
         list($scheme, $hierarchy) = $this->getSchemeAndHierarchy($dir);
 
         // If no scheme or scheme is "file" or "gs" (Google Cloud) create temp file in local filesystem
-        if (null === $scheme || 'file' === $scheme || 'gs' === $scheme) {
+        if ((null === $scheme || 'file' === $scheme || 'gs' === $scheme) && '' === $suffix) {
             $tmpFile = @tempnam($hierarchy, $prefix);
 
             // If tempnam failed or no scheme return the filename otherwise prepend the scheme
@@ -610,7 +612,7 @@ public function tempnam(string $dir, string $prefix)
         // Loop until we create a valid temp file or have reached 10 attempts
         for ($i = 0; $i < 10; ++$i) {
             // Create a unique filename
-            $tmpFile = $dir.'/'.$prefix.uniqid(mt_rand(), true);
+            $tmpFile = $dir.'/'.$prefix.uniqid(mt_rand(), true).$suffix;
 
             // Use fopen instead of file_exists as some streams do not support stat
             // Use mode 'x+' to atomically check existence and create to avoid a TOCTOU vulnerability

Tests/FilesystemTest.php

@@ -1509,6 +1509,22 @@ public function testTempnamOnUnwritableFallsBackToSysTmp()
         @unlink($filename);
     }
 
+    public function testTempnamWithSuffix()
+    {
+        $dirname = $this->workspace;
+        $filename = $this->filesystem->tempnam($dirname, 'foo', '.bar');
+        $this->assertStringEndsWith('.bar', $filename);
+        $this->assertFileExists($filename);
+    }
+
+    public function testTempnamWithSuffix0()
+    {
+        $dirname = $this->workspace;
+        $filename = $this->filesystem->tempnam($dirname, 'foo', '0');
+        $this->assertStringEndsWith('0', $filename);
+        $this->assertFileExists($filename);
+    }
+
     public function testDumpFile()
     {
         $filename = $this->workspace.\DIRECTORY_SEPARATOR.'foo'.\DIRECTORY_SEPARATOR.'baz.txt';