net: tests fail if /etc/hosts lists localhost 127.0.0.1 twice

[gopherbot]

by jaq@spacepants.org:

I just downloaded the source code release branch from code.google.com per the
instructions, then ran all.bash:

hg clone ...
hg update release
cd go/src
./all.bash
...
--- FAIL: TestLookupHost (0.00 seconds)
    hosts_test.go:65: LookupHost("localhost") = [127.0.0.1 127.0.0.1], has duplicate addresses
FAIL
FAIL    net 2.379s
...

My /etc/hosts is managed by a config management tool and just happens to have put two
localhost entries in there (I didn't know this until now ;-)

cat /etc/hosts
...
127.0.0.1   gunstar localhost
...
127.0.0.1   localhost   

The test seems a bit fragile because it relies on config outside the control of the Go
source code.

[gopherbot]

Comment 1 by jaq@spacepants.org:

I am not smart enough to understand the comment in that test:
"make sure it doesn't
    // duplicate addresses (a common bug due to the way
    // getaddrinfo works)."
getaddrinfo seems to be working as intended.

[rsc]

Comment 2:

Everything about the net tests is a little fragile. Even so, they serve a useful purpose.
What this test is referring to is that getaddrinfo will return 127.0.0.1 once for
SOCK_STREAM and once for SOCK_DGRAM, even when it appears just once in the hosts file.
In this case it has returned it four times, and the Go code has (correctly I think) cut
it down to two.
I'm inclined to leave this as is unless more people run into it.
Is it possible for you to get your /etc/hosts fixed?

Labels changed: added priority-later, removed priority-triage.

Status changed to Thinking.

[gopherbot]

Comment 3 by jaq@spacepants.org:

I thought that would be the response :)
I managed to get golang installed by removing the duplicate entry, but the configuration
management is out of my control.

[rsc]

Comment 4:

Labels changed: added go1.3maybe.

[rsc]

Comment 5:

Labels changed: added release-none, removed go1.3maybe.

[rsc]

Comment 6:

Labels changed: added repo-main.

[mikioh]

Closing. TestLookupHost was removed by 047f07a.