tree dda1e394caa751b3513bbc2b40bbd08b7caca914
parent a896219b3828165b568a35d2b80c1151f639eef8
author Heschi Kreinick <heschi@google.com> 1674668934 -0500
committer Gopher Robot <gobot@golang.org> 1674671934 +0000

internal/testpty: fix error handling

When calling a c library function, you discover that an error has
occurred, typically by looking at the return value of the function. Only
after that can you use errno to figure out the cause of the error.

Nothing about cgo changes that story -- you still have to look at the
result before checking the error that represents errno. If not you can
get false errors if the function happens to leak a non-zero errno.

Fix testpty to check errors correctly.

Change-Id: Idb95f8dd6a8ed63f653190c2e722e742cf50542b
Reviewed-on: https://go-review.googlesource.com/c/go/+/463397
Run-TryBot: Heschi Kreinick <heschi@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>