x/build/cmd/coordinator: building subrepos at run repo head

[bradfitz]

I just saw this during a trybot run:

https://storage.googleapis.com/go-build-log/25e0a367/linux-amd64_52c9862a.log

bootstrap/asm
# bootstrap/compile/internal/ssa
/tmp/workdir/go/src/cmd/compile/internal/ssa/opGen.go:8914[/tmp/workdir/go/pkg/bootstrap/src/bootstrap/compile/internal/ssa/opGen.go:8917]: cannot use []regMask literal (type []regMask) as type []outputInfo in field value
/tmp/workdir/go/src/cmd/compile/internal/ssa/opGen.go:8927[/tmp/workdir/go/pkg/bootstrap/src/bootstrap/compile/internal/ssa/opGen.go:8930]: cannot use []regMask literal (type []regMask) as type []outputInfo in field value
bootstrap/link/internal/amd64

It had never occurred on any prior run of trybots on https://go-review.googlesource.com/25001

I don't understand.

[bradfitz]

False alarm, @randall77. This is my and @adg's fault. The coordinator is running subrepo trybot tests at the wrong repo head. It's trying to run it at:

commit 25e0a367da6254d89b497f392ea9d1679455d000
Author: Keith Randall <khr@golang.org>
Date:   Wed Jul 13 16:15:54 2016 -0700

    [dev.ssa] cmd/compile: clean up tuple types and selects

    Make tuple types and their SelectX ops fully generic.
    These ops no longer need to be lowered.
    Regalloc understands them and their tuple-generating arguments.
    We can now have opcodes returning arbitrary pairs of results.
    (And it would be easy to move to >2 results if needed.)

    Update arm implementation to the new standard.
    Implement just enough in 386 port to do 64-bit add.

    Change-Id: I370ed5aacce219c82e1954c61d1f63af76c16f79
    Reviewed-on: https://go-review.googlesource.com/24976
    Reviewed-by: Cherry Zhang <cherryyz@google.com>
    Run-TryBot: Keith Randall <khr@golang.org>
    TryBot-Result: Gobot Gobot <gobot@golang.org>

... which is on the dev.ssa branch. It should be selecting master instead.

[bradfitz]

It looks like the coordinator's findWork function sets the branch head for the "go" repo by just looking at the first item in:

https://build.golang.org/?mode=json

Which is currently:

        "revisions": [
                {
                        "repo": "go",
                        "revision": "25e0a367da6254d89b497f392ea9d1679455d000",
                        "parentRevisions": [
                                "6b6de15d327142a19c978c8b9811310b174fd60b"
                        ],
                        "date": "2016-07-18T16:11:36Z",
                        "branch": "dev.ssa",
                        "author": "Keith Randall \u003ckhr@golang.org\u003e",
                        "desc": "[dev.ssa] cmd/compile: clean up tuple types and selects\n\nMake tuple types and their SelectX ops fully generic.\nThese ops no longer need to be lowered.\nRegalloc understands them and their tuple-generating arguments.\nWe can now have opcodes returning arbitrary pairs of results.\n(And it would be easy to move to \u003e2 results if needed.)\n\nUpdate arm implementation to the new standard.\nImplement just enough in 386 port to do 64-bit add.\n\nChange-Id: I370ed5aacce219c82e1954c61d1f63af76c16f79\nReviewed-on: ",

Looks like it should prefer the first "master" branch entry instead.

[gopherbot]

CL https://golang.org/cl/25008 mentions this issue.