x/tools/gopls: crash in mapPosition computing OutgoingCalls to unsafe.Slice

[ceearrashee]

gopls version: v0.15.3/go1.22.2
gopls flags:
update flags: proxy
extension version: 0.41.2
environment: Visual Studio Code win32
initialization error: undefined
issue timestamp: Thu, 18 Apr 2024 19:20:56 GMT
restart history:
Thu, 18 Apr 2024 18:12:44 GMT: activation (enabled: true)

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Failed to auto-collect gopls trace: no gopls log.

gopls stats -anon

{ "DirStats": { "Files": 5496, "TestdataFiles": 0, "GoFiles": 413, "ModFiles": 1, "Dirs": 383 }, "GOARCH": "amd64", "GOOS": "windows", "GOPACKAGESDRIVER": "", "GOPLSCACHE": "", "GoVersion": "go1.22.2", "GoplsVersion": "v0.15.3", "InitialWorkspaceLoadDuration": "5.9188475s", "MemStats": { "HeapAlloc": 135173400, "HeapInUse": 197967872, "TotalAlloc": 1481395568 }, "WorkspaceStats": { "Files": { "Total": 4366, "Largest": 6161825, "Errs": 0 }, "Views": [ { "GoCommandVersion": "go1.22.2", "AllPackages": { "Packages": 876, "LargestPackage": 279, "CompiledGoFiles": 4437, "Modules": 157 }, "WorkspacePackages": { "Packages": 108, "LargestPackage": 61, "CompiledGoFiles": 487, "Modules": 1 }, "Diagnostics": 0 } ] } }

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[Error - 22:20:56] Request textDocument/typeDefinition failed.
  Message: no type definition for SetCap
  Code: 0 
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x0 pc=0x169d61c]

goroutine 124273 [running]:
go/token.(*File).Name(...)
	C:/Program Files/Go/src/go/token/position.go:109
golang.org/x/tools/gopls/internal/golang.mapPosition({0x1da8368, 0xc01db76090}, 0x0?, {0x1da0060, 0xc00c826000}, 0x0, 0x7)
	C:/Users/eandr/go/pkg/mod/golang.org/x/tools/gopls@v0.15.3/internal/golang/definition.go:301 +0x5c
golang.org/x/tools/gopls/internal/golang.OutgoingCalls({0x1da8368?, 0xc01b477290?}, 0xc00c826000, {0x1daad80, 0xc0082e2ea0}, {0x132?, 0x0?})
	C:/Users/eandr/go/pkg/mod/golang.org/x/tools/gopls@v0.15.3/internal/golang/call_hierarchy.go:282 +0xb32
golang.org/x/tools/gopls/internal/server.(*server).OutgoingCalls(0xc0002c4000, {0x1da83a0?, 0xc021d9b3b0?}, 0xc032136460)
	C:/Users/eandr/go/pkg/mod/golang.org/x/tools/gopls@v0.15.3/internal/server/call_hierarchy.go:58 +0x195
golang.org/x/tools/gopls/internal/protocol.serverDispatch({0x1da83a0, 0xc021d9b3b0}, {0x1dc3120, 0xc0002c4000}, 0xc01b4771d0, {0x1da8560, 0xc00b8da680})
	C:/Users/eandr/go/pkg/mod/golang.org/x/tools/gopls@v0.15.3/internal/protocol/tsserver.go:131 +0x4daa
golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.ServerHandler.func3({0x1da83a0, 0xc021d9b3b0}, 0xc01b4771d0, {0x1da8560, 0xc00b8da680})
	C:/Users/eandr/go/pkg/mod/golang.org/x/tools/gopls@v0.15.3/internal/protocol/protocol.go:160 +0x85
golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.handshaker.func4({0x1da83a0, 0xc021d9b3b0}, 0xc01b4771d0, {0x1da8560, 0xc00b8da680})
	C:/Users/eandr/go/pkg/mod/golang.org/x/tools/gopls@v0.15.3/internal/lsprpc/lsprpc.go:509 +0x923
golang.org/x/tools/gopls/internal/protocol.Handlers.MustReplyHandler.func1({0x1da83a0, 0xc021d9b3b0}, 0xc0190a6528, {0x1da8560, 0xc00b8da680})
	C:/Users/eandr/go/pkg/mod/golang.org/x/tools@v0.18.1-0.20240412183611-d92ae0781217/internal/jsonrpc2/handler.go:35 +0xc6
golang.org/x/tools/gopls/internal/protocol.Handlers.AsyncHandler.func2.2()
	C:/Users/eandr/go/pkg/mod/golang.org/x/tools@v0.18.1-0.20240412183611-d92ae0781217/internal/jsonrpc2/handler.go:103 +0x96
created by golang.org/x/tools/gopls/internal/protocol.Handlers.AsyncHandler.func2 in goroutine 124
	C:/Users/eandr/go/pkg/mod/golang.org/x/tools@v0.18.1-0.20240412183611-d92ae0781217/internal/jsonrpc2/handler.go:100 +0x1c5
[Error - 22:20:56] 

[hyangah]

@ceearrashee Thanks for the report. It looks like browsing outgoing call hierarchy triggered the panic. Can you tell us more about when you observed this crash?

• Were you checking the function or method named SetCap?
• Did you notice other errors or problems before this crash? (code navigation not functioning, squiggles indicating problems in the code, etc)

@adonovan @findleyr Is this a known issue?

[findleyr]

@hyangah no this is not a known issue, though I don't think this code has changed in a long time.

@ceearrashee is this reproducible?

[adonovan]

I can reproduce this by computing a call hierarchy involving a call to unsafe.Slice.

These special functions cause no end of bugs.