x/tools/gopls: crash in debug.GetInstance during `go generate`

[iboware]

gopls version: v0.9.0 (go1.18.3)
gopls flags:
update flags: proxy
extension version: 0.34.1
go version: 1.18.3
environment: Visual Studio Code linux
initialization error: undefined
issue timestamp: Fri, 08 Jul 2022 13:08:32 GMT
restart history:
Fri, 08 Jul 2022 12:30:55 GMT: activation (enabled: true)
Fri, 08 Jul 2022 12:33:55 GMT: manual (enabled: true)
Fri, 08 Jul 2022 12:41:02 GMT: installation (enabled: true)

ATTENTION: PLEASE PROVIDE THE DETAILS REQUESTED BELOW.

Describe what you observed.

I was trying to generate mocks by gomock. it become unresponsive and then crashed.

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x30 pc=0x5fcd13]

goroutine 3629 [running]:
golang.org/x/tools/internal/xcontext.detachedContext.Value(...)
	  xcontext.go:23
golang.org/x/tools/internal/lsp/debug.GetInstance({0x1073d48%3F, 0xc0048489b0%3F})
	  serve.go:361  0x3e
golang.org/x/tools/internal/lsp/debug.makeGlobalExporter.func1({0x1073d48, 0xc0048489b0}, {{0xc0aa28f2297931d3, 0x13facda29, 0x158cae0}, {{{0x1072a78, 0xc000032120}, 0xa, {0xcc75c0, 0xdffb9b}}, ...}, ...}, ...)
	  serve.go:571  0x7e
golang.org/x/tools/internal/event/core.deliver({0x1073d48, 0xc0048489b0}, 0xc0002edbc0, {{0xc0aa28f2297931d3, 0x13facda29, 0x158cae0}, {{{0x1072a78, 0xc000032120}, 0xa, {0xcc75c0, ...}}, ...}, ...})
	  export.go:45  0xfd
golang.org/x/tools/internal/event/core.ExportPair({_, _}, {{0x0, 0x0, 0x0}, {{{0x1072a78, 0xc000032120}, 0xa, {0xcc75c0, 0xdffb9b}}, ...}, ...}, ...)
	  export.go:68  0x128
golang.org/x/tools/internal/event.Start({0x1073d48%3F, 0xc0048489b0%3F}, {0xdffb9b%3F, 0xc00870cde0%3F}, {0xc0085c3db0%3F, 0x0%3F, 0x0%3F})
	  event.go:91  0x358
golang.org/x/tools/internal/jsonrpc2.(*conn).Notify(0x0%3F, {0x1073d48, 0xc0048489b0}, {0xdffb9b, 0xa}, {0xca9de0%3F, 0xc00870cde0%3F})
	  conn.go:85  0x35b
golang.org/x/tools/internal/lsp/protocol.clientConn.Notify(...)
	  protocol.go:60
golang.org/x/tools/internal/lsp/protocol.(*clientDispatcher).Progress(0xd8a9a0%3F, {0x1073d48%3F, 0xc0048489b0%3F}, 0x7fe5f4067a68%3F)
	  tsclient.go:168  0x42
golang.org/x/tools/internal/lsp/progress.(*WorkDone).Report(0xc009af7d10, {0x0%3F, 0x0%3F}, {0xc00670f440, 0x25}, 0x0)
	  progress.go:188  0x27e
golang.org/x/tools/internal/lsp/progress.(*WorkDoneWriter).Write(0xc00870c560%3F, {0xc0011c2000%3F, 0x25, 0x44e7f2%3F})
	  progress.go:268  0x5c
io.(*multiWriter).Write(0xc004fe2348%3F, {0xc0011c2000, 0x25, 0x8000})
	  multi.go:60  0x86
io.copyBuffer({0x106d200, 0xc007157dd0}, {0x106d6e0, 0xc004fe2348}, {0x0, 0x0, 0x0})
	  io.go:428  0x204
io.Copy(...)
	  io.go:385
os/exec.(*Cmd).writerDescriptor.func1()
	  exec.go:311  0x3a
os/exec.(*Cmd).Start.func1(0x0%3F)
	  exec.go:444  0x25
created by os/exec.(*Cmd).Start
	  exec.go:443  0x795
[Error - 3:08:24 PM] 

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[findleyr]

Thank you for the report. Is this by any chance reproducible for you?

In any case, we can investigate this crashing stack.

[findleyr]

Reproduced with TestGenerateProgress, which was unfortunately skipped due to #49901 😞

Bisected to https://go.dev/cl/409936.

[gopherbot]

Change https://go.dev/cl/417115 mentions this issue: internal/lsp/progress: actually close of Context in WorkDoneWriter