fix(std/node): Stop callbacks being called twice when callback throws error (#8867)

1 files changed, 22 insertions, 0 deletions

diff --git a/std/node/_fs/_fs_copy_test.ts b/std/node/_fs/_fs_copy_test.ts
index c61fffb14..4fdf78cb0 100644
--- a/std/node/_fs/_fs_copy_test.ts
+++ b/std/node/_fs/_fs_copy_test.ts
@@ -1,5 +1,7 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+import * as path from "../../path/mod.ts";
 import { assert } from "../../testing/asserts.ts";
+import { assertCallbackErrorUncaught } from "../_utils.ts";
 import { copyFile, copyFileSync } from "./_fs_copy.ts";
 import { existsSync } from "./_fs_exists.ts";
 
@@ -29,3 +31,23 @@ Deno.test({
     Deno.removeSync(destFile);
   },
 });
+
+Deno.test("[std/node/fs] copyFile callback isn't called twice if error is thrown", async () => {
+  // The correct behaviour is not to catch any errors thrown,
+  // but that means there'll be an uncaught error and the test will fail.
+  // So the only way to test this is to spawn a subprocess, and succeed if it has a non-zero exit code.
+  // (assertThrowsAsync won't work because there's no way to catch the error.)
+  const tempDir = await Deno.makeTempDir();
+  const tempFile1 = path.join(tempDir, "file1.txt");
+  const tempFile2 = path.join(tempDir, "file2.txt");
+  await Deno.writeTextFile(tempFile1, "hello world");
+  const importUrl = new URL("./_fs_copy.ts", import.meta.url);
+  await assertCallbackErrorUncaught({
+    prelude: `import { copyFile } from ${JSON.stringify(importUrl)}`,
+    invocation: `copyFile(${JSON.stringify(tempFile1)}, 
+                          ${JSON.stringify(tempFile2)}, `,
+    async cleanup() {
+      await Deno.remove(tempDir, { recursive: true });
+    },
+  });
+});