basename() corrupts file path resolution when called between wp_upload_dir() and move_uploaded_file()

[smojef]

Description

$upload_dir = wp_upload_dir();
$test_call = basename('/a/b/c/d.ext');  // This causes the next line to fail
$result = move_uploaded_file($tmp_name, 'uploads/mec_events.xml');

PHP Warning:  move_uploaded_file(uploads/mec_events.xml): Failed to open stream: No such file or directory in /xxxxx/wp-content/test_upload_bug.php on line 153
PHP Warning:  move_uploaded_file(): Unable to move '/tmp/phpByMZrs' to 'uploads/mec_events.xml' in /xxxxx/wp-content/test_upload_bug.php on line 153

I created the following PHP file to try to identify the root cause of this strange issue and possible workarounds.
Place this PHP file in wp-content of a Wordpress site, run it upload any file that you rename as 'mec_events.xml' to reproduce the problem. For an unknown reason on my hosted server, the following scenarios fail: A1, A2, D, and F1.

<?php
require_once(__DIR__ . '/../wp-load.php');

$result_text = "";
$vars_dump = "";

if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_FILES['testfile']) && isset($_POST['test'])) {
    
    $test_num = $_POST['test'];
    
    if ($test_num == 'A1') {
        $test_name = "Baseline problem (fails)";

        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical failing scenario is when calling basename() between up_upload_dir() and move_uploaded_file()
        $upload_dir = wp_upload_dir();      
        $base_name = basename($name);  // This causes the move to fail
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/' . $base_name;
        $result = move_uploaded_file($tmp_name, $target);

        $vars = [
            'name' => $name,
            'pre_target' => $pre_target,
            'tmp_name' => $tmp_name,
            'base_name' => $base_name,
            'target' => $target,
            'result' => $result ? 'true' : 'false'
        ];

    } else if ($test_num == 'A2') {
        $test_name = "No prior influence (fails)";
        
        // Make sure that usleep() or file_exists() before critical section does not solve the problem
        $pre_target = 'uploads/mec_events.xml';
        usleep(50000);  
        $file_exists_before = file_exists($pre_target);
        
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical failing scenario is when calling basename() between up_upload_dir() and move_uploaded_file()
        $upload_dir = wp_upload_dir();      
        $base_name = basename($name);  // This causes the move to fail
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/' . $base_name;
        $result = move_uploaded_file($tmp_name, $target);

        $real_pre_target = realpath($pre_target);
        $real_target = realpath($target);
        $same_targets = ($real_target !== false && $real_pre_target !== false && $real_target === $real_pre_target);
        $vars = [
            'name' => $name,
            'pre_target' => $pre_target,
            'tmp_name' => $tmp_name,
            'base_name' => $base_name,
            'target' => $target,
            'same_targets' => $same_targets ? 'true' : 'false',
            'result' => $result ? 'true' : 'false'
        ];
        
    } elseif ($test_num == 'B1') {
        $test_name = "basename moved before (success)";
        
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];
        $base_name = basename($name); // Moved outside

        // No function calls between up_upload_dir() and move_uploaded_file()
        $upload_dir = wp_upload_dir();
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/' . $base_name;
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'base_name' => $base_name,
            'target' => $target,
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'B2') {
        $test_name = "No other call in between (success)";
        
        // No function calls between up_upload_dir() and move_uploaded_file()
        $upload_dir = wp_upload_dir();
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];
        $base_name = 'mec_events.xml'; // Removed call
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/' . $base_name;
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'result' => $result ? 'true' : 'false'
        ];     
        
    } elseif ($test_num == 'C') {
        $test_name = "Existing target and no other call in between (success)";
        
        $pre_target = 'uploads/mec_events.xml';
        usleep(50000);
        $file_created = file_put_contents($pre_target, 'dummy content');
        usleep(50000);
        $file_exists_before = file_exists($pre_target);
        
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];
        
        // Critical section
        $upload_dir = wp_upload_dir();
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/mec_events.xml';  // Hard coded, no basename
        $result = move_uploaded_file($tmp_name, $target);
        
        $real_pre_target = realpath($pre_target);
        $real_target = realpath($target);
        $same_targets = ($real_target !== false && $real_pre_target !== false && $real_target === $real_pre_target);        
        $vars = [
            'name' => $name,
            'pre_target' => $pre_target,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'file_created_before' => $file_created !== false ? 'YES' : 'NO',
            'file_exists_before_wp_upload_dir' => $file_exists_before ? 'YES' : 'NO',
            'same_targets' => $same_targets ? 'true' : 'false',
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'D') {
        $test_name = "Unrelated basename() call in between (fails)";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];
        $pre_target = 'uploads/mec_events.xml';
        
        // Critical section (minimal form)
        $upload_dir = wp_upload_dir();
        $test_call = basename('/a/b/c/d.ext');  // Unrelated inexisting path
        $result = move_uploaded_file($tmp_name, 'uploads/mec_events.xml');

        $base_name = basename($name);  // After success
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/' . $base_name;
        $real_pre_target = realpath($pre_target);
        $real_target = realpath($target);
        $same_targets = ($real_target !== false && $real_pre_target !== false && $real_target === $real_pre_target);
                
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'test_call' => $test_call,
            'same_targets' => $same_targets ? 'true' : 'false',
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'E1') {
        $test_name = "usleep(0) before basename() (success)";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical section
        $upload_dir = wp_upload_dir();
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/mec_events.xml';
        usleep(0);
        $base_name = basename($rand_path);
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'base_name' => $base_name,
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'E2') {
        $test_name = "usleep(0) after basename() (success)";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical section
        $upload_dir = wp_upload_dir();
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/mec_events.xml';
        $base_name = basename($rand_path);
        usleep(0);
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'base_name' => $base_name,
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'F1') {
        $test_name = "file_exists() before basename() (fail)";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical section
        $upload_dir = wp_upload_dir();
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/mec_events.xml';
        $file_exists_result = file_exists($target);
        $base_name = basename($rand_path);
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'file_exists_result' => $file_exists_result ? 'true' : 'false',
            'base_name' => $base_name,
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'F2') {
        $test_name = "file_exists() after basename() (success)";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical section
        $upload_dir = wp_upload_dir();
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/mec_events.xml';
        $base_name = basename($rand_path);
        $file_exists_result = file_exists($target);
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'file_exists_result' => $file_exists_result ? 'true' : 'false',
            'base_name' => $base_name,
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'G') {
        $test_name = "clearstatcache() and basename() (success)";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical section
        $upload_dir = wp_upload_dir();
        $test_call = clearstatcache(true);
        $base_name = basename($name);
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/' . $base_name;
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'test_call' => $test_call,
            'base_name' => $base_name,
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'H') {
        $test_name = "pathinfo() instead of basename() in between (success)";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical section
        $upload_dir = wp_upload_dir();      
        $base_name = pathinfo($name, PATHINFO_BASENAME); // Instead of basename
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/' . $base_name;
        $result = move_uploaded_file($tmp_name, $target);

        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'base_name' => $base_name,
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'I') {
        $test_name = "dirname() instead of basename() in between";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical section
        $upload_dir = wp_upload_dir();
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/mec_events.xml';
        $test_call = dirname($rand_path);
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'test_call' => $test_call,
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'J') {
        $test_name = "realpath() instead in between (success)";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical section
        $upload_dir = wp_upload_dir();
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/mec_events.xml';
        $test_call = realpath($rand_path);
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'test_call' => $test_call,
            'result' => $result ? 'true' : 'false'
        ];

    } elseif ($test_num == 'K') {
        $test_name = "is_file() instead in between (success)";
        
        $rand_path = '/a/b/c/d.ext';
        $files_testfile = $_FILES['testfile'];
        $name = $files_testfile['name'];
        $tmp_name = $files_testfile['tmp_name'];

        // Critical section
        $upload_dir = wp_upload_dir();
        $basedir = $upload_dir['basedir'];
        $target = $basedir . '/mec_events.xml';
        $test_call = is_file($rand_path);
        $result = move_uploaded_file($tmp_name, $target);
        
        $vars = [
            'name' => $name,
            'tmp_name' => $tmp_name,
            'target' => $target,
            'test_call' => $test_call,
            'result' => $result ? 'true' : 'false'
        ];

    }
    
    if ($result) @unlink($target);
    
    $vars_dump = print_r($vars, true);
    $result_text = "Test $test_num: $test_name = " . ($result ? "SUCCESS ✓" : "FAIL ✗");
    
    error_log($result_text);
    error_log("Variables: " . json_encode($vars));
}
?>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Tests PHP Wordpress Import Issues</title>
    <style>
        body { 
            font-family: Arial, sans-serif; 
            max-width: 900px; 
            margin: 40px auto; 
            padding: 20px;
        }
        h1 { color: #333; }
        .discovery {
            background: #c8e6c9;
            border-left: 4px solid #4CAF50;
            padding: 15px;
            margin: 20px 0;
        }
        .form-container {
            background: #f5f5f5;
            padding: 20px;
            border-radius: 8px;
            margin: 20px 0;
        }
        .test-option {
            margin: 10px 0;
            padding: 10px;
            background: white;
            border-left: 4px solid #2196F3;
            font-size: 14px;
        }
        .test-option input[type="radio"] {
            margin-right: 10px;
        }
        button {
            background: #2196F3;
            color: white;
            border: none;
            padding: 12px 24px;
            font-size: 16px;
            border-radius: 4px;
            cursor: pointer;
            margin: 5px;
        }
        .result-box {
            background: #e8f5e9;
            border: 2px solid #4CAF50;
            padding: 20px;
            margin: 20px 0;
            border-radius: 8px;
            font-family: monospace;
            font-size: 18px;
            font-weight: bold;
            text-align: center;
        }
        .result-box.fail {
            background: #ffebee;
            border-color: #f44336;
        }
        .vars-box {
            background: #fafafa;
            border: 1px solid #ccc;
            padding: 15px;
            margin: 20px 0;
            font-family: monospace;
            font-size: 12px;
            overflow-x: auto;
            white-space: pre;
        }
    </style>
</head>
<body>
    <h1>🔬 Upload any text file renamed 'mec_events.xml'</h1>
    
    <div class="form-container">
        <form method="post" enctype="multipart/form-data">
            
            <div class="test-option"><label><input type="radio" name="test" value="A1" required><strong>Test A1: ✗</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="A2" required><strong>Test A2: ✗</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="B1" required><strong>Test B1: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="B2" required><strong>Test B2: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="C" required><strong>Test C: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="D" required><strong>Test D: ✗</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="E1" required><strong>Test E1: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="E2" required><strong>Test E2: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="F1" required><strong>Test F1: ✗</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="F2" required><strong>Test F2: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="G" required><strong>Test G: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="H" required><strong>Test H: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="I" required><strong>Test I: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="J" required><strong>Test J: ✓</strong></label></div>
            <div class="test-option"><label><input type="radio" name="test" value="K" required><strong>Test K: ✓</strong></label></div>
        
            <input type="file" name="testfile" required style="margin: 15px 0; font-size: 16px;">
            <br>
            <button type="submit">▶️ Import</button>
        </form>
    </div>

    <?php if ($result_text): ?>
        <div class="result-box <?php echo strpos($result_text, 'FAIL') !== false ? 'fail' : ''; ?>" id="resultBox">
            <?php echo htmlspecialchars($result_text); ?>
        </div>
        
        <h3>Variables :</h3>
        <div class="vars-box" id="varsBox"><?php echo htmlspecialchars($vars_dump); ?></div>
        
        <button onclick="window.location.href=window.location.pathname">🔄 Restart</button>
    <?php endif; ?>

</body>
</html>
<!--
Log Results:

[16-Jan-2026 06:53:15 UTC] PHP Warning:  move_uploaded_file(/xxxxx/wp-content/uploads/mec_events.xml): Failed to open stream: No such file or directory in /xxxxx/wp-content/test_upload_bug.php on line 23
[16-Jan-2026 06:53:15 UTC] PHP Warning:  move_uploaded_file(): Unable to move '/tmp/phpGbqaSy' to '/xxxxx/wp-content/uploads/mec_events.xml' in /xxxxx/wp-content/test_upload_bug.php on line 23
[16-Jan-2026 06:53:15 UTC] PHP Warning:  Undefined variable $pre_target in /xxxxx/wp-content/test_upload_bug.php on line 27
[16-Jan-2026 06:53:15 UTC] Test A1: Baseline problem (fails) = FAIL ✗
[16-Jan-2026 06:53:15 UTC] Variables: {"name":"mec_events.xml","pre_target":null,"tmp_name":"\/tmp\/phpGbqaSy","base_name":"mec_events.xml","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","result":"false"}

[16-Jan-2026 06:53:34 UTC] PHP Warning:  move_uploaded_file(/xxxxx/wp-content/uploads/mec_events.xml): Failed to open stream: Connection reset by peer in /xxxxx/wp-content/test_upload_bug.php on line 55
[16-Jan-2026 06:53:34 UTC] PHP Warning:  move_uploaded_file(): Unable to move '/tmp/php0ZeaZZ' to '/xxxxx/wp-content/uploads/mec_events.xml' in /xxxxx/wp-content/test_upload_bug.php on line 55
[16-Jan-2026 06:53:34 UTC] Test A2: No prior influence (fails) = FAIL ✗
[16-Jan-2026 06:53:34 UTC] Variables: {"name":"mec_events.xml","pre_target":"uploads\/mec_events.xml","tmp_name":"\/tmp\/php0ZeaZZ","base_name":"mec_events.xml","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","same_targets":"true","result":"false"}

[16-Jan-2026 06:53:43 UTC] Test B1: basename moved before (success) = SUCCESS ✓
[16-Jan-2026 06:53:43 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/php4AUAsz","base_name":"mec_events.xml","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","result":"true"}

[16-Jan-2026 06:53:52 UTC] Test B2: No other call in between (success) = SUCCESS ✓
[16-Jan-2026 06:53:52 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/phpVgkVHg","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","result":"true"}

[16-Jan-2026 06:54:00 UTC] Test C: Existing target and no other call in between (success) = SUCCESS ✓
[16-Jan-2026 06:54:00 UTC] Variables: {"name":"mec_events.xml","pre_target":"uploads\/mec_events.xml","tmp_name":"\/tmp\/phpAjc1mr","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","file_created_before":"YES","file_exists_before_wp_upload_dir":"YES","same_targets":"true","result":"true"}

[16-Jan-2026 06:54:08 UTC] PHP Warning:  move_uploaded_file(uploads/mec_events.xml): Failed to open stream: No such file or directory in /xxxxx/wp-content/test_upload_bug.php on line 157
[16-Jan-2026 06:54:08 UTC] PHP Warning:  move_uploaded_file(): Unable to move '/tmp/php5EbII6' to 'uploads/mec_events.xml' in /xxxxx/wp-content/test_upload_bug.php on line 157
[16-Jan-2026 06:54:08 UTC] Test D: Unrelated basename() call in between (fails) = FAIL ✗
[16-Jan-2026 06:54:08 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/php5EbII6","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","test_call":"d.ext","same_targets":"true","result":"false"}

[16-Jan-2026 06:54:16 UTC] Test E1: usleep(0) before basename() (success) = SUCCESS ✓
[16-Jan-2026 06:54:16 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/phpZT2Zir","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","base_name":"d.ext","result":"true"}

[16-Jan-2026 06:54:23 UTC] Test E2: usleep(0) after basename() (success) = SUCCESS ✓
[16-Jan-2026 06:54:23 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/phpwrxS5n","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","base_name":"d.ext","result":"true"}

[16-Jan-2026 06:54:29 UTC] PHP Warning:  move_uploaded_file(/xxxxx/wp-content/uploads/mec_events.xml): Failed to open stream: No such file or directory in /xxxxx/wp-content/test_upload_bug.php on line 237
[16-Jan-2026 06:54:29 UTC] PHP Warning:  move_uploaded_file(): Unable to move '/tmp/phpUBrwwF' to '/xxxxx/wp-content/uploads/mec_events.xml' in /xxxxx/wp-content/test_upload_bug.php on line 237
[16-Jan-2026 06:54:29 UTC] Test F1: file_exists() before basename() (fail) = FAIL ✗
[16-Jan-2026 06:54:29 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/phpUBrwwF","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","file_exists_result":"false","base_name":"d.ext","result":"false"}

[16-Jan-2026 06:54:43 UTC] Test F2: file_exists() after basename() (success) = SUCCESS ✓
[16-Jan-2026 06:54:43 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/phpEaZvV7","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","file_exists_result":"true","base_name":"d.ext","result":"true"}

[16-Jan-2026 06:54:50 UTC] Test G: clearstatcache() and basename() (success) = SUCCESS ✓
[16-Jan-2026 06:54:50 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/phpLzVtvc","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","test_call":null,"base_name":"mec_events.xml","result":"true"}

[16-Jan-2026 06:55:07 UTC] Test H: pathinfo() instead of basename() in between (success) = SUCCESS ✓
[16-Jan-2026 06:55:07 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/phpMg3keB","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","base_name":"mec_events.xml","result":"true"}

[16-Jan-2026 06:55:15 UTC] Test I: dirname() instead of basename() in between = SUCCESS ✓
[16-Jan-2026 06:55:15 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/php1HYUkN","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","test_call":"\/a\/b\/c","result":"true"}

[16-Jan-2026 06:55:25 UTC] Test J: realpath() instead in between (success) = SUCCESS ✓
[16-Jan-2026 06:55:25 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/phpdMya0u","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","test_call":false,"result":"true"}

[16-Jan-2026 06:55:32 UTC] Test K: is_file() instead in between (success) = SUCCESS ✓
[16-Jan-2026 06:55:32 UTC] Variables: {"name":"mec_events.xml","tmp_name":"\/tmp\/php7gSzrn","target":"\/xxxxx\/wp-content\/uploads\/mec_events.xml","test_call":false,"result":"true"}

-->

PHP Version

PHP 8.2.28 (cli) (built: Apr  7 2025 13:21:15) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.2.28, Copyright (c) Zend Technologies
    with Zend OPcache v8.2.28, Copyright (c), by Zend Technologies
    with SourceGuardian v16.0.2, Copyright (c) 2000-2025, by SourceGuardian Ltd.

Operating System

cloudlinux.com 4.18.0-553.8.1.el8_10.x86_64 #1 SMP

[iluuu1994]

Hi @smojef. I tried your example but could not reproduce the issue. All the cases you marked to fail succeeded for me. I did however try with PHP 8.4. 8.2 has stopped active support over a year ago, so please try with a newer PHP version to verify this issue still exists.

[smojef]

Hi @iluuu1994, Thanks for taking the time to test this for me. It really helps. I did upgrade to this PHP version:

PHP 8.4.12 (cli) (built: Aug 27 2025 19:25:20) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.4.12, Copyright (c) Zend Technologies

And the problem is now solved!
At least this is now documented, so if anyone encounters the same issue, they wont have to spend 5h investigating ;-)