buffer: zero-fill buffer allocated with invalid content

Zero-fill when `Buffer.alloc()` receives invalid fill data.

A solution like https://github.com/nodejs/node/pull/17427 which switches
to throwing makes sense, but is likely a breaking change.

This suggestion leaves the behaviour of `buffer.fill()` untouched,
since any change to it would be a breaking change, and lets
`Buffer.alloc()` check whether any filling took place or not.

PR-URL: https://github.com/nodejs/node/pull/17428
Refs: https://github.com/nodejs/node/pull/17427
Refs: https://github.com/nodejs/node/issues/17423
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/test/parallel/test-buffer-fill.js b/test/parallel/test-buffer-fill.js
index 63db4ce13c..681207e95e 100644
--- a/test/parallel/test-buffer-fill.js
+++ b/test/parallel/test-buffer-fill.js
@@ -468,3 +468,9 @@ assert.strictEqual(
 assert.strictEqual(
   Buffer.allocUnsafeSlow(16).fill('Љ', 'utf8').toString('utf8'),
   'Љ'.repeat(8));
+
+{
+  const buf = Buffer.from('a'.repeat(1000));
+  buf.fill('This is not correctly encoded', 'hex');
+  assert.strictEqual(buf.toString(), 'a'.repeat(1000));
+}