gopls: automated issue report (crash) [panic: slice out of bounds, v0.15.3/go1.22.2]

[rusq]

Hey team, I tried to add as much information as I could, but please let me know if any additional diag is needed.

Reproduce

1. Install goyacc

   go install golang.org/x/tools/cmd/goyacc@latest
   

2. Run the following command to generate y.go and y.output

   goyacc slacktime.y
   

3. Open "y.go" file in VSCode.

4. Observe the Gopls crash.

To confirm:

1. Restart the Gopls server
2. It crashes again

Notes

slacktime.y is C version of the grammar file, so "y.go" will not work straight away. I was just planning to adapt it to Goyacc, but ran into this issue. I suspect it is similar to #3351 which was recently opened as well.

I'm attaching an archive of the project files. There's no sensitive information, it's just an experimental code.

• the gopls log is in gopls.log.
• the reproduction steps are duplicated in REPRODUCE.md, should you need them
• generate-y.go.sh contains the command to generate y.go, should it be required.
• "slacktime.l" has nothing to do with this, just there for completeness.
• I have not included irrelevant slacktime.h files nor the implementation of functions handle_slacktime, which is irrelevant and would only add entropy, but can share them as well if needed.

HERE WE GO:
gopls-issue-project.tar.gz

Thank you, and please let me know if anything else is required?

Orignial Report

gopls version: v0.15.3/go1.22.2
gopls flags:
update flags: proxy
extension version: 0.41.2
environment: Visual Studio Code darwin
initialization error: undefined
issue timestamp: Sat, 20 Apr 2024 04:36:43 GMT
restart history:
Sat, 20 Apr 2024 04:35:52 GMT: activation (enabled: true)
Sat, 20 Apr 2024 04:36:42 GMT: installation (enabled: true)

ATTENTION: PLEASE PROVIDE THE DETAILS REQUESTED BELOW.

Describe what you observed.

Important

I have opened the y.go file from the attached archive. Y.go file is the go file generated by goyacc tool. See Reproduce above.

panic: runtime error: slice bounds out of range [3:2]

goroutine 125 [running]:
golang.org/x/tools/gopls/internal/protocol.(*Mapper).LineCol8Position(0xc0001d0f00, 0x2, 0x0)
	  mapper.go:151  0x1a5
golang.org/x/tools/gopls/internal/cache.goPackagesErrorDiagnostics.func1({{0xc000240c40, 0xd}, {0xc000800280, 0x1c}, 0x1}, 0x1c%3F, {0x676e900, 0xc0001abb00}, {0x6776d00, 0xc00060a0f0})
	  errors.go:58  0x145
golang.org/x/tools/gopls/internal/cache.goPackagesErrorDiagnostics({0x6776d00, 0xc00060a0f0}, {{0xc000240c40, 0xd}, {0xc000800280, 0x1c}, 0x1}, 0xc000346100, {0x676e900, 0xc0001abb00})
	  errors.go:69  0xf5
golang.org/x/tools/gopls/internal/cache.computeLoadDiagnostics({0x6776d00, 0xc00060a0f0}, 0xc0001abb00, 0xc000346100)
	  load.go:541  0x185
golang.org/x/tools/gopls/internal/cache.(*packageHandleBuilder).buildPackageHandle(0xc000230140, {0x6776d00, 0xc00060a0f0}, 0xc00060a0a0)
	  check.go:1129  0x2b7
golang.org/x/tools/gopls/internal/cache.(*Snapshot).getPackageHandles.func2.1()
	  check.go:932  0xce
golang.org/x/sync/errgroup.(*Group).Go.func1()
	  errgroup.go:78  0x56
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 179
	  errgroup.go:75  0x96

gopls stats -anon

gopls stats -anon failed after 136 ms. Please check if gopls is killed by OS.

OPTIONAL: If you would like to share more information, you can attach your complete gopls logs.

NOTE: THESE MAY CONTAIN SENSITIVE INFORMATION ABOUT YOUR CODEBASE.
DO NOT SHARE LOGS IF YOU ARE WORKING IN A PRIVATE REPOSITORY.

[rusq]

Probably this should have been opened in gopls issues, but I blame extension for opening this page when I pressed "report"!

[rusq]

I have tested with the previous versions, here are my results:

gopls version	Works?
v0.14.2	✅
v0.15.0	❌
v0.15.1	❌
v0.15.2	❌

GoPLS v0.14.2 output (that did not crash):

[Info  - 15:12:57] 2024/04/20 15:12:57 go info for /Users/anon/wp/_experiments/_c/goslackdump-time
(go dir /Users/anon/wp/_experiments/_c/goslackdump-time)
(go version go version go1.22.2 darwin/amd64)
(valid build configuration = true)
(build flags: [])
(selected go env: [GO111MODULE=, GOCACHE=/Users/anon/Library/Caches/go-build, GOFLAGS=, GOMODCACHE=/Users/anon/go/pkg/mod, GOPATH=/Users/anon/go, GOPRIVATE=bitbucket.org/dbvisitsoftware,github.com/rusq,bitbucket.org/128,bitbucket.org/puritron,github.com/vend, GOROOT=/usr/local/Cellar/go/1.22.2/libexec, GOWORK=])


[Info  - 15:12:57] 2024/04/20 15:12:57 go/packages.Load #1
	snapshot=0
	directory=file:///Users/anon/wp/_experiments/_c/goslackdump-time
	query=[/Users/anon/wp/_experiments/_c/goslackdump-time/... builtin]
	packages=2

[Info  - 15:12:57] 2024/04/20 15:12:57 go/packages.Load #1: updating metadata for 1 packages

[Error - 15:12:57] 2024/04/20 15:12:57 unable to compute positions for parse errors: no parsed file for file:///Users/anon/wp/_experiments/_c/goslackdump-time/slacktime.y in goslackdumptime
	package="goslackdumptime"

[Error - 15:12:57] 2024/04/20 15:12:57 imports fixes: AllImportsFixes: /Users/anon/wp/_experiments/_c/goslackdump-time/slacktime.y:2: illegal character U+0023 '#'
	file="/Users/anon/wp/_experiments/_c/goslackdump-time/y.go"

[Error - 15:12:57] 2024/04/20 15:12:57 unable to compute positions for parse errors: no parsed file for file:///Users/anon/wp/_experiments/_c/goslackdump-time/slacktime.y in goslackdumptime
	package="goslackdumptime"

[findleyr]

Thank you for the reproducer and detailed report. This looks like a dupe of golang/go#66875, so I'll close it in favor of that issue.

The reproducer will make this much easier to fix.