net: in (*netFD).dial, use the passed in local address if getsockname fails

'man getsockname' lists a number of possible failure modes, including
ENOBUFS (for resource exhaustion) and EBADF (which we could possibly
see in the event of a bug or race condition elsewhere in the program).

If getsockname fails for an explicit user-provided local address, the
user is probably not expecting LocalAddr on the returned net.Conn to
return nil. This may or may not fix #34611, but should at least help
us diagnose it more clearly.

While we're add it, also add more nil-checking logic in the test based
on the stack traces posted to
https://golang.org/issue/34611#issuecomment-975923748.

For #34611

Change-Id: Iba870b96787811e4b9959b74ef648afce9316602
Reviewed-on: https://go-review.googlesource.com/c/go/+/366536
Trust: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

0 files changed, 0 insertions, 0 deletions