internal/lsp: fix deadlock in type-checking

Fixes golang/go#33992

Change-Id: I4e27501d1c619887038dfa77cc9cf064c966ff43
Reviewed-on: https://go-review.googlesource.com/c/tools/+/193317
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>

internal/lsp/cache/file.go

@@ -57,6 +57,7 @@ func (f *fileBase) View() source.View {
 func (f *fileBase) Handle(ctx context.Context) source.FileHandle {
 	f.handleMu.Lock()
 	defer f.handleMu.Unlock()
+
 	if f.handle == nil {
 		f.handle = f.view.Session().GetFile(f.URI())
 	}

internal/lsp/cache/gofile.go

@@ -40,14 +40,6 @@ type goFile struct {
 	meta map[packageID]*metadata
 }
 
-type astFile struct {
-	uri       span.URI
-	file      *ast.File
-	err       error // parse errors
-	ph        source.ParseGoHandle
-	isTrimmed bool
-}
-
 func (f *goFile) GetToken(ctx context.Context) (*token.File, error) {
 	file, err := f.GetAST(ctx, source.ParseFull)
 	if file == nil {

internal/lsp/cache/load.go

@@ -54,10 +54,22 @@ func (view *view) load(ctx context.Context, f *goFile) (map[packageID]*metadata,
 	view.mcache.mu.Lock()
 	defer view.mcache.mu.Unlock()
 
+	var toDelete []packageID
+	f.mu.Lock()
+	for id, cph := range f.pkgs {
+		if cph != nil {
+			toDelete = append(toDelete, id)
+		}
+	}
+	f.mu.Unlock()
+
 	// If the AST for this file is trimmed, and we are explicitly type-checking it,
 	// don't ignore function bodies.
 	if f.wrongParseMode(ctx, source.ParseFull) {
-		f.invalidateAST(ctx)
+		// Remove the package and all of its reverse dependencies from the cache.
+		for _, id := range toDelete {
+			f.view.remove(ctx, id, map[packageID]struct{}{})
+		}
 	}
 
 	// Get the metadata for the file.

internal/lsp/cache/view.go

@@ -365,26 +365,24 @@ func (f *goFile) invalidateContent(ctx context.Context) {
 	f.view.mcache.mu.Lock()
 	defer f.view.mcache.mu.Unlock()
 
+	var toDelete []packageID
+	f.mu.Lock()
+	for id, cph := range f.pkgs {
+		if cph != nil {
+			toDelete = append(toDelete, id)
+		}
+	}
+	f.mu.Unlock()
+
 	f.handleMu.Lock()
 	defer f.handleMu.Unlock()
 
-	f.invalidateAST(ctx)
-	f.handle = nil
-}
-
-// invalidateAST invalidates the AST of a Go file,
-// including any position and type information that depends on it.
-func (f *goFile) invalidateAST(ctx context.Context) {
-	f.mu.Lock()
-	cphs := f.pkgs
-	f.mu.Unlock()
-
 	// Remove the package and all of its reverse dependencies from the cache.
-	for id, cph := range cphs {
+	for _, id := range toDelete {
-		if cph != nil {
 		f.view.remove(ctx, id, map[packageID]struct{}{})
 	}
-	}
+
+	f.handle = nil
 }
 
 // remove invalidates a package and its reverse dependencies in the view's