Prepare for the removal of HH\Lib\Path

Author: lexidor

src/Response/TemporaryFileSapiEmitter.hack

@@ -34,27 +34,33 @@ final class TemporaryFileSapiEmitter implements EmitterInterface {
 
 		$body = $response->getBody();
 
-		/* HH_FIXME[4053] */
-		$path = $body->getPath();
-
-		$path as File\Path;
+		// Lambda is used to force $path to be string, not TAny (`_`).
+		$path = (): string ==> {
+			/*HH_FIXME[4053] getPath is not part of the WriteHandle interface.*/
+			$path_maybe_object = $body->getPath();
+			// Path is going to be removed from the hsl.
+			// We just used `->toString()` anyway.
+			// This hacky expression is needed, because `$path_maybe_object`
+			// is of the TAny type (`_`), so the typechecker won't error when
+			// `->getPath()` starts returning a string.
+			// This expression works for both Path and string.
+			return $path_maybe_object |> $$ is string ? $$ : $$->toString();
+		}();
 
 		$this->writeStatusLine($response);
 		$this->writeHeaders($response);
 
-		$temporary_file_path = $path->toString();
-
 		if ($body is IO\CloseableHandle) {
 			$body->close();
 		}
 
-		$read_handle = File\open_read_only($temporary_file_path);
+		$read_handle = File\open_read_only($path);
 		using ($read_handle->closeWhenDisposed()) {
 			$out = IO\request_output();
 			$content = await $read_handle->readAllAsync();
 			await $out->writeAllAsync($content);
 		};
-		\unlink($temporary_file_path);
+		\unlink($path);
 	}
 
 	/**