cmd/pprof: update the vendored tool from upstream

[ALTree]

Opening this to document a recent (failed) effort to update pprof from upstream.

The tool was successfully updated from upstream on March 1 (CL 37652). A failed attempt to a final update for go1.9 was made on June 20 (CL 46155). The update broke several builders and was immediately reverted.

The failing builders:

• We had an OSX10.8 failure, an OSX10.10 failure, and failures on the darwin-arm-a1549ios and darwin-arm64-a1549ios builders. All these failures were on the recently introduced TestHttpsInsecure test. I reported the issue upstream (TestHttpsInsecure failures on certain darwin builders google/pprof#146).

• Both the android builders were failing (failure1, failure2), again, on TestHttpsInsecure, but with a different error (related to filesystem permissions, apparently).

• The linux-arm-arm5spacemonkey was failing on the TestHttpsInsecure test, with the same error we got on the android builders (issues with filesystem permissions).

• Two of the plan9 builders (plan9-386 and plan9-arm) were failing (failure1, failure2), again, on TestHttpsInsecure, with the same error we got on the darwin builders.

To sum it up: all the failures are on the TestHttpsInsecure test. Darwin and plan9 builders are failing because the test somehow generates bad/unexpected profiles(?). A linux-arm5 builder and both the android builders are failing with errors related to bad filesystem permission (I suspect the test makes assumptions about write permissions on certain folders that do not hold on some of the builders).

[aalexand]

google/pprof#169 should fix the file system related issue on Android.

TestHttpsInsecure test is special in that it is the only test that collects the data by starting a Go server and a spinning goroutine and profiling the server. Hence these new issues found.

Is it possible to add building and testing of google/pprof at tip to the Go build matrix, "Sub-repositories at tip" section? This would continuously ensure that pprof is Go vendoring ready.

[ALTree]

Is it possible to add building and testing of google/pprof at tip to the Go build matrix, "Sub-repositories at tip" section? This would continuously ensure that pprof is Go vendoring ready.

@bradfitz is it possible/do we want this?

[bradfitz]

We want that, yes. And everything's possible with a bit of time. We're short on time. But if somebody wants to work on #14594, that'd be great.

[aalexand]

@ALTree google/pprof#146 was fixed, can you try updating pprof in Go vendoring area again?

[ALTree]

@aalexand nice! I could send a change but it won't be merged now because we're deep deep into the code freeze. I'll send a change as soon as the tree re-open for go1.10 in August.

[aalexand]

@ALTree Could you create the change just to see if all the tests pass?

[ALTree]

I can do that, but what platforms are you interested in? For example, we have an OSX10.8 builder but not an OSX10.8 trybot. Builders run on master after a commit, trybots can be used to test a change before committing it.

So even if I upload a change and run the trybots on it, they won't tell us if the OSX10.8 issue is gone. In fact, with the old failed update in June the trybots said "OK" on my change and only after it was merged I noticed the OSX10.8, OSX10.10 and iPhone failures (by looking at the builders webpage).

[aalexand]

I see. Then it doesn't make much sense, no. I didn't know the set of trybot envs is limited.

[gopherbot]

Change https://golang.org/cl/57370 mentions this issue: cmd/vendor/github.com/google/pprof: refresh from upstream