x/tools/gopls: "internal error reading (shared cache|typerefs data|symbol data)" bug (ENOSPC?)

[adonovan]

#!stacks
("bug.Reportf" || "bug.Errorf") && 
  ("runCached:21" || "runCached:+24" || "runCached:+18" || /* analysis */
   "typerefData:+5" ||  /* typerefs */
   "cache.(*Snapshot).Symbols.func1:+15") /* symbols */

Note that similar errors have been observed in three different places that call filecache.Get, as indicated by the comments in the pattern above. Presumably the underlying cause is the same in all cases.

This stack -iVK7w was reported by telemetry:

	// Access the cache.
	var summary *analyzeSummary
	const cacheKind = "analysis"
	if data, err := filecache.Get(cacheKind, key); err == nil {
		// cache hit
		analyzeSummaryCodec.Decode(data, &summary)
		if summary == nil { // debugging #66732
			bug.Reportf("analyzeSummaryCodec.Decode yielded nil *analyzeSummary")
		}
	} else if err != filecache.ErrNotFound {
		return nil, bug.Errorf("internal error reading shared cache: %v", err) // <--- here
	} else {

gopls/bug
golang.org/x/tools/gopls/internal/util/bug.report:+35
golang.org/x/tools/gopls/internal/util/bug.Errorf:+2
golang.org/x/tools/gopls/internal/cache.(*analysisNode).runCached:+24
golang.org/x/tools/gopls/internal/cache.(*Snapshot).Analyze.func6.1:+4
golang.org/x/sync/errgroup.(*Group).Go.func1:+3
runtime.goexit:+0

golang.org/x/tools/gopls@v0.15.3 go1.20.4 windows/amd64 vscode (1)

Issue created by golang.org/x/tools/gopls/internal/telemetry/cmd/stacks.

Dups: m4MTKQ UFNCpw e960MA T1ADGg HYjhzQ S3fsGA n0XcvA pM2JYg m1H29g 9gpe3A 3NAjKw hLEI6Q 5wa4iw RRKzTQ VhQfxA o46Q6Q

[adonovan]

The possible causes of this failure are:

• can't create cache (e.g. disk full?)
• can't hash executable (e.g. gopls unlinked, or chmodded?)
• I/O error reading index file (e.g. EACCES, EISDIR, ENOENT?)

The first seems the most likely. The others can only happen if someone is meddling with the executable or the cache directory.

[adonovan]

Very different stack, but same cause. (Probably the same user given the rarity, timing, and OS/ARCH.)

func (s *Snapshot) typerefData(ctx context.Context, id PackageID, imports map[ImportPath]*metadata.Package, cgfs []file.Handle) ([]byte, error) {
	key := typerefsKey(id, imports, cgfs)
	if data, err := filecache.Get(typerefsKind, key); err == nil {
		return data, nil
	} else if err != filecache.ErrNotFound {
		bug.Reportf("internal error reading typerefs data: %v", err) // <-- here
	}

This stack m4MTKQ was reported by telemetry:

gopls/bug
golang.org/x/tools/gopls/internal/util/bug.report:+35
golang.org/x/tools/gopls/internal/util/bug.Reportf:+1
golang.org/x/tools/gopls/internal/cache.(*Snapshot).typerefData:+5
golang.org/x/tools/gopls/internal/cache.(*Snapshot).typerefs:+8
golang.org/x/tools/gopls/internal/cache.(*packageHandleBuilder).buildPackageHandle:+19
golang.org/x/tools/gopls/internal/cache.(*Snapshot).getPackageHandles.func2.1:+8
golang.org/x/sync/errgroup.(*Group).Go.func1:+3
runtime.goexit:+0

golang.org/x/tools/gopls@v0.15.3 go1.20.4 windows/amd64 vscode (1)

Issue created by golang.org/x/tools/gopls/internal/telemetry/cmd/stacks.