451: ensure Windows relative path expansion happens before creation of extension path

Author: asgrim

src/Platform/TargetPhp/PhpBinaryPath.php

@@ -107,18 +107,20 @@ public function extensionPath(): string
                 return $extensionPath;
             }
 
+            // `extension_dir` may be a relative URL on Windows, so resolve it according to the location of PHP
+            if (self::operatingSystem() === OperatingSystem::Windows) {
+                $phpPath              = dirname($this->phpBinaryPath);
+                $attemptExtensionPath = $phpPath . DIRECTORY_SEPARATOR . $extensionPath;
+
+                if (file_exists($attemptExtensionPath) && is_dir($attemptExtensionPath)) {
+                    return $attemptExtensionPath;
+                }
+            }
+
             // if the path is absolute, try to create it
             if (mkdir($extensionPath, 0777, true) && file_exists($extensionPath) && is_dir($extensionPath)) {
                 return $extensionPath;
             }
-
-            // `extension_dir` may be a relative URL on Windows, so resolve it according to the location of PHP
-            $phpPath              = dirname($this->phpBinaryPath);
-            $attemptExtensionPath = $phpPath . DIRECTORY_SEPARATOR . $extensionPath;
-
-            if (file_exists($attemptExtensionPath) && is_dir($attemptExtensionPath)) {
-                return $attemptExtensionPath;
-            }
         }
 
         throw new RuntimeException('Could not determine extension path for ' . $this->phpBinaryPath);