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internal/lsp: fix deadlock between f.mu and f.handleMu
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This change propagates the file handle through the type-checking
process, ensuring that the same handle is used throughout. It also
removes the ordering constraint that f.mu needs to be acquired before
f.handleMu. To make this more correct, we should associate a cached
package only with a FileHandle, but this relies on correct cache
invalidation, so that will be addressed in future changes.

Updates golang/go#34052

Change-Id: I6645046bfd15c882619a7f01f9b48c838de42a30
Reviewed-on: https://go-review.googlesource.com/c/tools/+/193718
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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@stamblerre
stamblerre committed Sep 5, 2019
1 parent 1d492ad commit 4f238b9
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Showing 2 changed files with 18 additions and 27 deletions.
27 changes: 9 additions & 18 deletions internal/lsp/cache/gofile.go
View file
Expand Up @@ -63,14 +63,14 @@ func (f *goFile) GetToken(ctx context.Context) (*token.File, error) {

func (f *goFile) GetAST(ctx context.Context, mode source.ParseMode) (*ast.File, error) {
ctx = telemetry.File.With(ctx, f.URI())
fh := f.Handle(ctx)

if f.isDirty(ctx) || f.wrongParseMode(ctx, mode) {
if err := f.view.loadParseTypecheck(ctx, f); err != nil {
if f.isDirty(ctx, fh) || f.wrongParseMode(ctx, fh, mode) {
if err := f.view.loadParseTypecheck(ctx, f, fh); err != nil {
return nil, err
}
}
// Check for a cached AST first, in case getting a trimmed version would actually cause a re-parse.
fh := f.Handle(ctx)
cached, err := f.view.session.cache.cachedAST(fh, mode)
if cached != nil || err != nil {
return cached, err
Expand Down Expand Up @@ -127,9 +127,10 @@ func (f *goFile) GetPackage(ctx context.Context) (source.Package, error) {

func (f *goFile) GetCheckPackageHandles(ctx context.Context) ([]source.CheckPackageHandle, error) {
ctx = telemetry.File.With(ctx, f.URI())
fh := f.Handle(ctx)

if f.isDirty(ctx) || f.wrongParseMode(ctx, source.ParseFull) {
if err := f.view.loadParseTypecheck(ctx, f); err != nil {
if f.isDirty(ctx, fh) || f.wrongParseMode(ctx, fh, source.ParseFull) {
if err := f.view.loadParseTypecheck(ctx, f, fh); err != nil {
return nil, err
}
}
Expand Down Expand Up @@ -192,11 +193,10 @@ func bestCheckPackageHandle(uri span.URI, cphs []source.CheckPackageHandle) (sou
return result, nil
}

func (f *goFile) wrongParseMode(ctx context.Context, mode source.ParseMode) bool {
func (f *goFile) wrongParseMode(ctx context.Context, fh source.FileHandle, mode source.ParseMode) bool {
f.mu.Lock()
defer f.mu.Unlock()

fh := f.Handle(ctx)
for _, cph := range f.pkgs {
for _, ph := range cph.Files() {
if fh.Identity() == ph.File().Identity() {
Expand All @@ -219,7 +219,7 @@ func (f *goFile) Builtin() (*ast.File, bool) {

// isDirty is true if the file needs to be type-checked.
// It assumes that the file's view's mutex is held by the caller.
func (f *goFile) isDirty(ctx context.Context) bool {
func (f *goFile) isDirty(ctx context.Context, fh source.FileHandle) bool {
f.mu.Lock()
defer f.mu.Unlock()

Expand All @@ -239,7 +239,6 @@ func (f *goFile) isDirty(ctx context.Context) bool {
if len(f.missingImports) > 0 {
return true
}
fh := f.Handle(ctx)
for _, cph := range f.pkgs {
for _, file := range cph.Files() {
// There is a type-checked package for the current file handle.
Expand All @@ -252,14 +251,6 @@ func (f *goFile) isDirty(ctx context.Context) bool {
}

func (f *goFile) GetActiveReverseDeps(ctx context.Context) (files []source.GoFile) {
f.mu.Lock()
meta := f.meta
f.mu.Unlock()

if meta == nil {
return nil
}

seen := make(map[packageID]struct{}) // visited packages
results := make(map[*goFile]struct{})

Expand All @@ -269,7 +260,7 @@ func (f *goFile) GetActiveReverseDeps(ctx context.Context) (files []source.GoFil
f.view.mcache.mu.Lock()
defer f.view.mcache.mu.Unlock()

for _, m := range meta {
for _, m := range f.metadata() {
f.view.reverseDeps(ctx, seen, results, m.id)
for f := range results {
if f == nil {
Expand Down
18 changes: 9 additions & 9 deletions internal/lsp/cache/load.go
View file
Expand Up @@ -18,11 +18,11 @@ import (
errors "golang.org/x/xerrors"
)

func (view *view) loadParseTypecheck(ctx context.Context, f *goFile) error {
func (view *view) loadParseTypecheck(ctx context.Context, f *goFile, fh source.FileHandle) error {
ctx, done := trace.StartSpan(ctx, "cache.view.loadParseTypeCheck", telemetry.URI.Of(f.URI()))
defer done()

meta, err := view.load(ctx, f)
meta, err := view.load(ctx, f, fh)
if err != nil {
return err
}
Expand Down Expand Up @@ -51,7 +51,7 @@ func (view *view) loadParseTypecheck(ctx context.Context, f *goFile) error {
return nil
}

func (view *view) load(ctx context.Context, f *goFile) ([]*metadata, error) {
func (view *view) load(ctx context.Context, f *goFile, fh source.FileHandle) ([]*metadata, error) {
ctx, done := trace.StartSpan(ctx, "cache.view.load", telemetry.URI.Of(f.URI()))
defer done()

Expand All @@ -72,15 +72,15 @@ func (view *view) load(ctx context.Context, f *goFile) ([]*metadata, error) {

// 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) {
if f.wrongParseMode(ctx, fh, source.ParseFull) {
// 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.
meta, err := view.checkMetadata(ctx, f)
meta, err := view.checkMetadata(ctx, f, fh)
if err != nil {
return nil, err
}
Expand All @@ -92,10 +92,10 @@ func (view *view) load(ctx context.Context, f *goFile) ([]*metadata, error) {

// checkMetadata determines if we should run go/packages.Load for this file.
// If yes, update the metadata for the file and its package.
func (v *view) checkMetadata(ctx context.Context, f *goFile) ([]*metadata, error) {
func (v *view) checkMetadata(ctx context.Context, f *goFile, fh source.FileHandle) ([]*metadata, error) {
// Check if we need to re-run go/packages before loading the package.
f.mu.Lock()
runGopackages := v.shouldRunGopackages(ctx, f)
runGopackages := v.shouldRunGopackages(ctx, f, fh)
metadata := f.metadata()
f.mu.Unlock()

Expand Down Expand Up @@ -178,7 +178,7 @@ func sameSet(x, y map[packagePath]struct{}) bool {
// shouldRunGopackages reparses a file's package and import declarations to
// determine if they have changed.
// It assumes that the caller holds the lock on the f.mu lock.
func (v *view) shouldRunGopackages(ctx context.Context, f *goFile) (result bool) {
func (v *view) shouldRunGopackages(ctx context.Context, f *goFile, fh source.FileHandle) (result bool) {
defer func() {
// Clear metadata if we are intending to re-run go/packages.
if result {
Expand All @@ -196,7 +196,7 @@ func (v *view) shouldRunGopackages(ctx context.Context, f *goFile) (result bool)
return true
}
// Get file content in case we don't already have it.
parsed, err := v.session.cache.ParseGoHandle(f.Handle(ctx), source.ParseHeader).Parse(ctx)
parsed, err := v.session.cache.ParseGoHandle(fh, source.ParseHeader).Parse(ctx)
if err == context.Canceled {
log.Error(ctx, "parsing file header", err, tag.Of("file", f.URI()))
return false
Expand Down

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