cmd/go: install parallelism is broken

[niemeyer]

This script:

    #!/bin/bash 
    set -e 
    while true; do 
            date 
            rm -rf $GOPATH/pkg/linux_amd64 
            GOMAXPROCS=1 go install -x -work launchpad.net/juju-core/cmd/... 
    done

Breaks down after a couple of tries with errors like:

    pack: non-object file $WORK/launchpad.net/juju-core/cmd/_obj/_go_.6

Preserving the working directory with -work or hacking the code to disable the mkdir
cache do not fix the problem.

Running it without parallelism with -p 1 makes it work reliably.

The full log of such a broken build is attached.

Attachments:

1. log.txt (37653 bytes)

[niemeyer]

Comment 1:

Owner changed to ---.

[rsc]

Comment 2:

Does go list launchpad.net/juju-core/cmd/... have any duplicates?

[niemeyer]

Comment 3:

% go list launchpad.net/juju-core/cmd/... 
launchpad.net/juju-core/cmd/
launchpad.net/juju-core/cmd/juju
launchpad.net/juju-core/cmd/jujuc
launchpad.net/juju-core/cmd/jujuc/server
launchpad.net/juju-core/cmd/jujud

[rsc]

Comment 4:

Labels changed: added priority-later, go1.1, removed priority-triage.

Status changed to Accepted.

[rsc]

Comment 5:

Labels changed: added size-m.

[rsc]

Comment 6:

Does this still happen for you? I believe the problem is that the wildcard x/... is
including x/ (instead of x) as one of its expansions. Other things depend on juju/cmd
and so the build ends up building both juju/cmd/ and juju/cmd, which end up stepping on
each other. You can see the problem in the 'go list' output you gave, where the first
line listed ends in a slash. However, I cannot reproduce this locally: go list hash/...
lists 'hash' not 'hash/'. Perhaps another cleanup fixed this.

[niemeyer]

Comment 7:

I can confirm that the slash went away, and that retrying the operation doesn't break in
the same way anymore (related or not).
Thanks for pinging.

Status changed to Fixed.