cmd/cover: cover mode "atomic" generates invalid code for files without a newline at EOF #58370

nilium · 2023-02-06T23:41:41Z

What version of Go are you using (`go version`)?

$ go version
go version go1.20 linux/amd64

Does this issue reproduce with the latest release?

Yes.

It does not reproduce under Go 1.19.5.
Also does not reproduce with GOEXPERIMENT=nocoverageredesign and suggests the issue is possibly a regression related to cmd/cover: extend coverage testing to include applications #51430 -- thanks to @deltamualpha for discovering this.

What operating system and processor architecture are you using (`go env`)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/ncower/.cache/go-build"
GOENV="/home/ncower/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/ncower/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/ncower/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.20"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/ncower/p/break/go.mod"
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 -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build76322923=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Ran go test -cover -covermode=atomic on a package with a file that had a newline missing at EOF.

All code referred to is also under https://github.com/nilium/go-issue-test/tree/38c0047d4219026ecccbb2f35f96162fef5478a7. Because it involves the trailing newline at EOF on sources, there isn't a good way to reproduce it in the playground as far as I can see.

A more or less empty file can be used to reproduce this provided the empty.go file does not have a newline at EOF:

empty.go

package noeol

some_test.go (doesn't matter if this file has a newline at EOF to reproduce)

package noeol

import "testing"

func TestNothing(t *testing.T) {
}

What did you expect to see?

For test output:

$ go test -cover -covermode=atomic ./noeol
ok      github.com/nilium/go-issue-test/noeol   0.001s  coverage: [no statements]

What did you see instead?

$ go test -cover -covermode=atomic ./noeol
# github.com/nilium/go-issue-test/noeol [github.com/nilium/go-issue-test/noeol.test]
noeol/empty.go:2:51: syntax error: unexpected var after top level declaration
FAIL    github.com/nilium/go-issue-test/noeol [build failed]
FAIL

with the generated code for mode=atomic resembling the following:

//line noeol/empty.go:1:1
// empty.go
package noeol; import _cover_atomic_ "sync/atomic"var _ = _cover_atomic_.LoadUint32

var CoverageVariableNameP uint32
// etc.

The text was updated successfully, but these errors were encountered:

deltamualpha · 2023-02-07T15:07:28Z

@thanm will probably be interested in this?

thanm · 2023-02-07T15:15:10Z

Thanks for the report. I'll take a look. NB as in many other cases, you can help reduce the frequency of this sort of surprise by running your code through "gofmt".

gopherbot · 2023-02-07T16:14:18Z

Change https://go.dev/cl/466115 mentions this issue: cmd/cover: fix buglet in -covermode=atomic fixup

dr2chase · 2023-02-08T16:09:17Z

Not sure if this is backport-worthy.

nilium · 2023-02-08T16:58:11Z

Not sure if this is backport-worthy.

Since it only seems to affect Go 1.20 out of the box where the coverage redesign is in use by default, probably not.

Fix a minor buglet in atomic mode fixup that would generate non-compilable code for a package containing only the "package X" clause with no trailing newline following the "X". Fixes golang#58370. Change-Id: I0d9bc4f2b687c6bd913595418f6db7dbe50cc5df Reviewed-on: https://go-review.googlesource.com/c/go/+/466115 Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>

Bug: golang/go#58370

Fixes an "syntax error: unexpected var after top level declaration" error when running 'go test -cover -covermode=atomic ./...' with GO 1.20. Related to GO issue: golang/go#58370

pWoLiAn · 2023-06-08T16:57:53Z

this issue still exists even on 1.20.5, when running atomic coverage on test files with no new line at EOF🤔

thanm · 2023-06-09T13:24:40Z

this issue still exists even on 1.20.5, when running atomic coverage on test files with no new line at EOF

That is expected, given that the bugfix hasn't been ported to the 1.20 release branch.

pWoLiAn · 2023-06-09T16:09:19Z

That is expected, given that the bugfix hasn't been ported to the 1.20 release branch.

Oh, thanks for letting me know. I was under the impression the fix was released since the issue was closed/merged PR.
Any particular reason as to why the fix hasn't been released yet?

thanm · 2023-06-09T16:31:50Z

See https://github.com/golang/go/wiki/MinorReleases .

"Our default decision should always be to not backport, but fixes for security issues, serious problems with no workaround, and documentation fixes are backported to the most recent two release branches, if applicable to that branch. "

A “serious” problem is one that prevents a program from working at all.

- see [cmd/cover: cover mode "atomic" generates invalid code for files without a newline at EOF](golang/go#58370)

* ci: fix wrong coverage result on badge * chore: adjust go test command * chore: disable `atomic` covermode to avoid go bug - see [cmd/cover: cover mode "atomic" generates invalid code for files without a newline at EOF](golang/go#58370)

…58370

* update entitlements to go1.20 * add whitespace to avoid bug: golang/go#58370 --------- Co-authored-by: Daniel Agbay <Daniel Agbay>

thanm self-assigned this Feb 7, 2023

thanm added the NeedsFix The path to resolution is known, but the work has not been done. label Feb 7, 2023

gopherbot closed this as completed in da93766 Feb 8, 2023

golightlyb mentioned this issue Feb 20, 2023

Go syntax error with Coveralls, but nowhere else lemurheavy/coveralls-public#1697

Closed

smoser mentioned this issue Mar 15, 2023

Build improvements project-stacker/stacker#443

Merged

thanm mentioned this issue Mar 27, 2023

cmd/cover: Compilation error when using -covermode=atomic on a file without a newline at the end #59081

Closed

swi-jared added a commit to solarwinds/appoptics-apm-go that referenced this issue Apr 21, 2023

Add newline to workaround bug in Go 1.20

45b73be

Bug: golang/go#58370

bitoku mentioned this issue May 2, 2023

Bump golang to 1.20 coredns/coredns#6067

Closed

This was referenced May 8, 2023

Add a trailing newline to fix GO 1.20 test compile error modfin/henry#2

Merged

Go fmt project. modern-go/concurrent#2

Open

100gle added a commit to 100gle/wordcounter that referenced this issue Jun 28, 2023

chore: disable atomic covermode to avoid go bug

28d2db0

- see [cmd/cover: cover mode "atomic" generates invalid code for files without a newline at EOF](golang/go#58370)

cristaloleg mentioned this issue Jul 11, 2023

cmd/go: go test -race -coverpkg=all AST-parser is broken #60403

Closed

ffeldmann added a commit to ffeldmann/webhooks that referenced this issue Dec 17, 2023

Adds newline to fix test case. Looks like a bug in go1.20: golang/go#…

9e52504

…58370

dagbay-rh pushed a commit to dagbay-rh/entitlements-api-go that referenced this issue Jan 17, 2024

add whitespace to avoid bug: golang/go#58370

1fcd5b6

dagbay-rh added a commit to RedHatInsights/entitlements-api-go that referenced this issue Jan 17, 2024

update entitlements to go1.20 (#163)

67128e1

* update entitlements to go1.20 * add whitespace to avoid bug: golang/go#58370 --------- Co-authored-by: Daniel Agbay <Daniel Agbay>

leodido mentioned this issue Jan 25, 2024

ci: fix Go 1.20 covermode atomic tests leodido/go-urn#35

Merged

darccio added a commit to DataDog/dd-trace-go that referenced this issue Mar 21, 2024

contrib/google.golang.org/grpc: go fmt (re: golang/go#58370)

6934f7f

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cmd/cover: cover mode "atomic" generates invalid code for files without a newline at EOF #58370

cmd/cover: cover mode "atomic" generates invalid code for files without a newline at EOF #58370

nilium commented Feb 6, 2023

deltamualpha commented Feb 7, 2023

thanm commented Feb 7, 2023

gopherbot commented Feb 7, 2023

dr2chase commented Feb 8, 2023

nilium commented Feb 8, 2023

pWoLiAn commented Jun 8, 2023

thanm commented Jun 9, 2023

pWoLiAn commented Jun 9, 2023

thanm commented Jun 9, 2023

cmd/cover: cover mode "atomic" generates invalid code for files without a newline at EOF #58370

cmd/cover: cover mode "atomic" generates invalid code for files without a newline at EOF #58370

Comments

nilium commented Feb 6, 2023

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

What did you do?

What did you expect to see?

What did you see instead?

deltamualpha commented Feb 7, 2023

thanm commented Feb 7, 2023

gopherbot commented Feb 7, 2023

dr2chase commented Feb 8, 2023

nilium commented Feb 8, 2023

pWoLiAn commented Jun 8, 2023

thanm commented Jun 9, 2023

pWoLiAn commented Jun 9, 2023

thanm commented Jun 9, 2023

What version of Go are you using (`go version`)?

What operating system and processor architecture are you using (`go env`)?