Handle situation (in CI/CD pipeline, for instance) when tag informati…

…on is not available

build/scripts/phar-set-timestamps/run.php

@@ -10,8 +10,40 @@
 
 if (is_string(getenv('SOURCE_DATE_EPOCH'))) {
     $epoch = (int) getenv('SOURCE_DATE_EPOCH');
+
+    printf(
+        'Setting timestamp of files in PHAR to %d (based on environment variable SOURCE_DATE_EPOCH)' . PHP_EOL,
+        $epoch
+    );
 } else {
-    $epoch = (int) trim(shell_exec('git log -1 --format=%at ' . trim(shell_exec('git describe --abbrev=0'))));
+    $tag = shell_exec('git describe --abbrev=0');
+
+    if (is_string($tag) && strpos($tag, 'fatal') === false) {
+        $tmp = shell_exec('git log -1 --format=%at ' . trim($tag));
+
+        if (is_string($tag) && is_numeric(trim($tmp))) {
+            $epoch = (int) trim($tmp);
+
+            printf(
+                'Setting timestamp of files in PHAR to %d (based on when tag %s was created)' . PHP_EOL,
+                $epoch,
+                trim($tag)
+            );
+        }
+
+        unset($tmp);
+    }
+
+    unset($tag);
+}
+
+if (!isset($epoch)) {
+    $epoch = time();
+
+    printf(
+        'Setting timestamp of files in PHAR to %d (based on current time)' . PHP_EOL,
+        $epoch
+    );
 }
 
 $timestamp = new DateTime;