x/tools/gopls/internal/analysis/fillstruct: stack overflow in populateValue

[adonovan]

#!stacks
"crash/crash" && "fillstruct.populateValue:+135"

Issue created by stacks.

func populateValue(f *ast.File, pkg *types.Package, typ types.Type) ast.Expr {
	switch u := typ.Underlying().(type) {
...	case *types.Pointer:
		switch types.Unalias(u.Elem()).(type) {
		case *types.Basic: ...
		default:
			x := populateValue(f, pkg, u.Elem())         <--- here

This stack 4zukbQ was reported by telemetry:

• crash/crash
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+0
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135
• golang.org/x/tools/gopls/internal/analysis/fillstruct.populateValue:+135

golang.org/x/tools/gopls@v0.17.1 go1.23.3 windows/amd64 vscode (4)

[adonovan]

Seems like something as simple as type P *P; type S struct { p P }; var _ = S{‸} might trigger this, but that didn't work for me.

[gabyhelp]

Related Issues

• x/tools/gopls: analysisinternal.ZeroValue crash on (presumably) unsafe.Pointer #70585 (closed)
• x/tools/gopls: stack overflow with type parameters (built with go1.18beta1) #50881 (closed)
• x/tools/gopls: failed *types.Func type assertion in populateCommentCompletions #71273 (closed)
• x/tools/gopls: sigpanic in persistent.(*mapNode).forEach #71115
• x/tools/gopls: Completion: failed type assertion in completer.item #71044 (closed)
• x/tools/go/analysis,gopls: infinite recursion in the copylock analyzer #61678 (closed)
• x/tools/gopls: Rename: crash due to Info.Defs[id]=nil bug in checkStructField #70968
• x/tools/gopls: OOM reported by fatal in runtime.mallocgc (windows) #70445 (closed)
• x/tools/gopls: panic: unknown basic type, struct has unsafe.Pointer #52640 (closed)
• x/tools/gopls: completion: failed type assertion in inferExpectedTypeArg #70889 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[findleyr]

Named types are handled separately, so this looks like either a type checker bug, or perhaps someone doing some security related testing on a huge buffer full of *s.

[findleyr]

Moving this to the backlog, as absent a recurrence I suspect this is a low priority. Certainly I don't know how to make progress.