issues when upgrading to the latest release

[RaduBerinde]

Hi,

I am hoping we can get some help to move CockroachDB to the latest release of go-tools.
We have a TestUnused is trying to run the unused checker. This is the change I made to it so it builds with the new release: (only the lint_test.go file is relevant): https://github.com/cockroachdb/cockroach/compare/master...RaduBerinde:update-honnef?expand=1#diff-24cf5c91d964c43f696360c5bc9286f8

With this change, it builds but the test times out after 10 minutes, using 30+GB RAM. For reference, with the previous version it runs for 30s.

I am hoping someone can take a quick look over the diff and check if I'm doing something egregiously wrong; if I'm not, then there must be a problem with the unused checker.

[dominikh]

With which version(s) of Go does this occur? 1.10 or 1.11 or both? What's the exact invocation/set of packages passed to unused?

[RaduBerinde]

The packages are all packages in https://github.com/cockroachdb/cockroach/tree/master/pkg:
paths := ctx.ImportPaths([]string{cockroachDB + "/pkg/..."})

This was with 1.10. Hm, I just tried it with 1.11 and it finishes (but it spits out a ton of problems, basically everything that isn't used within its own package). I'm invoking it with this:

		paths := ctx.ImportPaths([]string{cockroachDB + "/pkg/..."})

		unusedChecker := unused.NewChecker(unused.CheckAll)
		unusedChecker.WholeProgram = true

		problems, err := lintutil.Lint(
			[]lint.Checker{unused.NewLintChecker(unusedChecker)},
			paths,
			&opt,
		)

Is there a known issue in go 1.10 that's fixed in 1.11?

[dominikh]

Is there a known issue in go 1.10 that's fixed in 1.11?

Not as such, but the two employ different ways of loading packages and have different performance characteristics in doing so. There is also #377 which may be related.

[RaduBerinde]

I see, thanks! We're switching to go 1.11 anyway, so that's all good. I still don't know how to correctly invoke it so that it only reports values that are not used in any of the packages (with the invocation above it shows everything that's not used within the package it's defined).

This is how we were doing it with 2017.2.2: https://github.com/cockroachdb/cockroach/blob/master/pkg/testutils/lint/lint_test.go#L839

[dominikh]

I will look at it when I get the chance.

[RaduBerinde]

Thank you so much for your help! No rush whatsoever!

[RaduBerinde]

I worked on this some more and I just needed to set LintTests. Closing, thanks for the help!