cmd/go: list with -export and -covermode=atomic fails to build

[maxsours]

Go version

go version go1.21.6 darwin/arm64

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='arm64'
GOBIN=''
GOCACHE='~/Library/Caches/go-build'
GOENV='~/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='~/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='~/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.21.6'
GCCGO='gccgo'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/dev/null'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/y8/kc0q4v_x1454fr__4l32j26w0000gp/T/go-build2219730342=/tmp/go-build -gno-record-gcc-switches -fno-common'

What did you do?

$ go list -export -cover -race cmd/nm
# cmd/nm
/usr/local/go/src/cmd/nm/doc.go:41:37: could not import sync/atomic (open : no such file or directory)
cmd/nm

What did you see happen?

$ go list -export -cover -race cmd/nm
# cmd/nm
/usr/local/go/src/cmd/nm/doc.go:41:37: could not import sync/atomic (open : no such file or directory)
cmd/nm

What did you expect to see?

go build -cover -race works as expected. We would expect the go list command to succeed as well.
When running go list ... with -work, we can see sync/atomic is correctly added to the *.cover.go files, but it is not included in importcfg:

# import config
packagefile bufio=~/Library/Caches/go-build/b9/b98806a14c72980fa955342a2ffef07b871d95ac024cd8fd668021668be97816-d
packagefile cmd/internal/objfile=~/Library/Caches/go-build/b9/b9262c3ee809db084e17516b1c55810e3f3150e22831e4f4eafbf1a888855364-d
packagefile flag=~/Library/Caches/go-build/13/139eccd9f3144df8ee6480494307f2b06aa9bf19ba2f74cb4c7f9d14115d7819-d
packagefile fmt=~/Library/Caches/go-build/a3/a37fb0a0c11e799c4992ab511760fee037811f5481a1f7c4cf63ce7e08c3a0e6-d
packagefile log=~/Library/Caches/go-build/f1/f18a69602c944d8e4e1364a2d89a5c45cb101025319fb7c4cbe6a196fe249832-d
packagefile os=~/Library/Caches/go-build/d6/d64010892cba9d91f2fd56ee1177c4e1a48b5012f9ae1f58b8825412d853c590-d
packagefile sort=~/Library/Caches/go-build/0d/0daf4569d16ea11206c9465ae9f23f50a11e2ac546adbf32f8dc054a301e08d5-d
packagefile runtime=~/Library/Caches/go-build/e1/e1997716a043c5092d7ab1465a0a8e05c834335e26d446fedf0f9c4ac0c349d7-d
packagefile runtime/coverage=~/Library/Caches/go-build/e3/e30bc0cbef27b51d08c1ea7c44994cc02766dd15dd6435600a5ede665bb052c0-d

[bcmills]

cmd/go adds the implicit dependency on sync/atomic here:
https://cs.opensource.google/go/go/+/master:src/cmd/go/internal/load/pkg.go;l=3507-3510;drc=36b14a78b58924a8aea22c8949c3b8a4b7045d8b

The call chain is via:

• load.SelectCoverPackages
• load.PrepareForCoverageBuild
• list.runList

So the question is: is this a typestate bug (with the error happening before the call to PrepareForCoverageBuild, or is something in that call chain not reaching where we expect it to?

(attn @thanm)

[cixel]

My very hazy understanding is that it's an issue in runList:

EnsureImport updates a package's Internal.Imports and is adding the sync/atomic package.

This needs to happen before AutoAction creates the Action for cmd/nm, because it reads nm's Internal.Imports to populate Deps. These are what are used when printing the importcfg.

Locally, I was able to get the repro command to work by calling PrepareForCoverageBuild before creating the Action:

diff --git a/src/cmd/go/internal/list/list.go b/src/cmd/go/internal/list/list.go
index 92020da946..3fd697f3df 100644
--- a/src/cmd/go/internal/list/list.go
+++ b/src/cmd/go/internal/list/list.go
@@ -723,6 +723,9 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
                b.IsCmdList = true
                b.NeedExport = *listExport
                b.NeedCompiledGoFiles = *listCompiled
+               if cfg.Experiment.CoverageRedesign && cfg.BuildCover {
+                       load.PrepareForCoverageBuild(pkgs)
+               }
                a := &work.Action{}
                // TODO: Use pkgsFilter?
                for _, p := range pkgs {
@@ -730,9 +733,6 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
                                a.Deps = append(a.Deps, b.AutoAction(work.ModeInstall, work.ModeInstall, p))
                        }
                }
-               if cfg.Experiment.CoverageRedesign && cfg.BuildCover {
-                       load.PrepareForCoverageBuild(pkgs)
-               }
                b.Do(ctx, a)
        }

[mknyszek]

In triage, I think we're waiting for @thanm to take a look. Don't mean to assign you work though, so feel free to comment and unassign. Thanks! :)

[gopherbot]

Change https://go.dev/cl/560236 mentions this issue: cmd/go: fix build config before creating actions for 'go list -cover'

[cixel]

Change https://go.dev/cl/560236 mentions this issue: cmd/go: fix build config before creating actions for 'go list -cover'

I tried my hand at submitting a patch. It's quite small. Happy to take direction if my CL is incomplete or incorrect, or else close it and get out of the way to let a maintainer handle it. 😅