x/tools/gopls: crash with modules named "command-line-arguments"

[Martin-Jia]

gopls version: v0.12.4 (go1.20.6)
gopls flags:
update flags: proxy
extension version: 0.39.1
go version: 1.20.6
environment: Visual Studio Code linux
initialization error: undefined
issue timestamp: Wed, 19 Jul 2023 16:26:40 GMT
restart history:
Wed, 19 Jul 2023 16:26:31 GMT: activation (enabled: true)

ATTENTION: PLEASE PROVIDE THE DETAILS REQUESTED BELOW.

Describe what you observed.

Failed to open any go file. It showed up that the gopls server crashed. Reopen window did not help.

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0xb8 pc=0xbfb1f8]

goroutine 3867 [running]:
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).getPackageHandles.func1({0xc000e66080, 0x1a})
	  check.go:787  0x178
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).getPackageHandles.func1({0xc001034e40, 0x52})
	  check.go:788  0x1d7
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).getPackageHandles(0xc00440c000, {0x115b1f8, 0xc004359170}, {0xc0043579c0, 0x1, 0x0%3F})
	  check.go:792  0x246
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).forEachPackage(0x115b1f8%3F, {0x115b1f8, 0xc004358ff0}, {0xc0043579c0, 0x1, 0x1}, 0xc0043579c0%3F, 0x0%3F)
	  check.go:341  0x1d9
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).PackageDiagnostics(0xc003e04f68%3F, {0x115b1f8%3F, 0xc003aff380%3F}, {0xc0043579c0, 0x1, 0x1})
	  snapshot.go:666  0x1fc
golang.org/x/tools/gopls/internal/lsp.(*Server).diagnosePkgs.func1()
	  diagnostics.go:441  0x1dc
created by golang.org/x/tools/gopls/internal/lsp.(*Server).diagnosePkgs
	  diagnostics.go:434  0x205
[Error - 4:26:38 PM] 

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.

<OPTIONAL: ATTACH LOGS HERE>

[Martin-Jia]

[Info - 4:26:38 PM] 2023/07/19 16:26:38 go/packages.Load golang/vscode-go#1: updating metadata for 593 packages

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0xb8 pc=0xbfb1f8]

goroutine 3867 [running]:
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).getPackageHandles.func1({0xc000e66080, 0x1a})
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/check.go:787 +0x178
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).getPackageHandles.func1({0xc001034e40, 0x52})
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/check.go:788 +0x1d7
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).getPackageHandles(0xc00440c000, {0x115b1f8, 0xc004359170}, {0xc0043579c0, 0x1, 0x0?})
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/check.go:792 +0x246
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).forEachPackage(0x115b1f8?, {0x115b1f8, 0xc004358ff0}, {0xc0043579c0, 0x1, 0x1}, 0xc0043579c0?, 0x0?)
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/check.go:341 +0x1d9
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).PackageDiagnostics(0xc003e04f68?, {0x115b1f8?, 0xc003aff380?}, {0xc0043579c0, 0x1, 0x1})
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/snapshot.go:666 +0x1fc
golang.org/x/tools/gopls/internal/lsp.(*Server).diagnosePkgs.func1()
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/diagnostics.go:441 +0x1dc
created by golang.org/x/tools/gopls/internal/lsp.(*Server).diagnosePkgs
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/diagnostics.go:434 +0x205
[Error - 4:26:38 PM] Connection to server got closed. Server will not be restarted.

[findleyr]

Hi @Martin-Jia are you able to reproduce this reliable? Is this on an open-source repository?

[Martin-Jia]

Yes I can reproduce this reliable. This is not an open source repo.

[findleyr]

@Martin-Jia could you please try installing gopls@master? The panic has been enhanced with more information. It would be incredibly helpful if you could assist us in investigating.

git clone go.googlesource.com/tools
cd tools/gopls
go install

CC @adonovan

[Martin-Jia]

Thanks @findleyr
I'm not sure if I did wrong. I couldn't clone the repo from googlesource.com, so I tried go install golang.org/x/tools/gopls@master instead, and restarted vscode.
But I saw nothing different.

[Info - 10:58:22 AM] 2023/07/21 10:58:22 go/packages.Load golang/vscode-go#6: updating metadata for 548 packages

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0xb8 pc=0xbfb1f8]

goroutine 21960 [running]:
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).getPackageHandles.func1({0xc0009503c0, 0x1e})
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/check.go:787 +0x178
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).getPackageHandles.func1({0xc0074c3b60, 0x52})
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/check.go:788 +0x1d7
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).getPackageHandles(0xc00d240900, {0x115b1f8, 0xc00e8de420}, {0xc00e8c1b60, 0x1, 0x0?})
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/check.go:792 +0x246
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).forEachPackage(0x115b1f8?, {0x115b1f8, 0xc00e8de2a0}, {0xc00e8c1b60, 0x1, 0x1}, 0xc00e8c1b60?, 0x0?)
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/check.go:341 +0x1d9
golang.org/x/tools/gopls/internal/lsp/cache.(*snapshot).PackageDiagnostics(0xc00e295f68?, {0x115b1f8?, 0xc00e220150?}, {0xc00e8c1b60, 0x1, 0x1})
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/cache/snapshot.go:666 +0x1fc
golang.org/x/tools/gopls/internal/lsp.(*Server).diagnosePkgs.func1()
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/diagnostics.go:441 +0x1dc
created by golang.org/x/tools/gopls/internal/lsp.(*Server).diagnosePkgs
/home/mingj/go/pkg/mod/golang.org/x/tools/gopls@v0.12.4/internal/lsp/diagnostics.go:434 +0x205
[Error - 10:58:22 AM] Connection to server got closed. Server will not be restarted.

[Martin-Jia]

We later found that the issue may potentially relate with the project module name. The module name used to be "command-line-arguments". After we changed it to another one, for example, github.com/x/y/z, the issue just disappeared.
Another phenomenon I have observed was that if the module named as github.com/command-line-arguments, it still had the error, though those who use goland just worked fine.

[findleyr]

Aha! Thanks for the clue. Yes, I think that may do it. I'll try to reproduce and fix.