fs: fixup negative length in fs.truncate

`fs.ftruncate`, `fsPromises.truncate`, and `fsPromises.ftruncate`
all adjust negative lengths to 0 before invoking the system call.
`fs.truncate()` was the one outlier.

This "fixes" https://github.com/nodejs/node/issues/35632 but in the
opposite direction than discussed in the issue -- specifically by
removing an EINVAL error from one function rather than adding it to
another.

Signed-off-by: James M Snell <jasnell@gmail.com>
Fixes: https://github.com/nodejs/node/issues/35632

PR-URL: https://github.com/nodejs/node/pull/37483
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/test/parallel/test-fs-truncate.js b/test/parallel/test-fs-truncate.js
index 418d56c047d..de9687ebb27 100644
--- a/test/parallel/test-fs-truncate.js
+++ b/test/parallel/test-fs-truncate.js
@@ -280,3 +280,19 @@ function testFtruncate(cb) {
     );
   });
 });
+
+{
+  const file1 = path.resolve(tmp, 'truncate-file-1.txt');
+  fs.writeFileSync(file1, 'Hi');
+  fs.truncateSync(file1, -1);  // Negative coerced to 0, No error.
+  assert(fs.readFileSync(file1).equals(Buffer.alloc(0)));
+}
+
+{
+  const file1 = path.resolve(tmp, 'truncate-file-2.txt');
+  fs.writeFileSync(file1, 'Hi');
+  // Negative coerced to 0, No error.
+  fs.truncate(file1, -1, common.mustSucceed(() => {
+    assert(fs.readFileSync(file1).equals(Buffer.alloc(0)));
+  }));
+}