internal/lsp/regtest: allow sharing memoized results across regtests

Each regtest does a significant amount of extra work re-doing things
like parsing and type-checking the runtime package. We can share this
work across regtests by using a shared cache, significantly speeding
them up at the cost of potentially hiding bugs related to timing.

Sharing this work still retains most of the benefit of the regtests, so
implement this in the default mode (formerly called "singleton" and now
renamed to "default"). In a subsequent CL, modes will be cleaned up so
that "default" is the only mode that runs with -short.

Making this change actually revealed a caching bug: our cached package
stores error messages extracted from go/packages errors, but does not
include these errors in the cache key. Fix this by hashing all metadata
errors into the package cache key.

Updates golang/go#39384

Change-Id: I37ab9604149d34c9a79fc02b0e1bc23fcb17c454
Reviewed-on: https://go-review.googlesource.com/c/tools/+/417587
TryBot-Result: Gopher Robot <[email protected]>
gopls-CI: kokoro <[email protected]>
Run-TryBot: Robert Findley <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>

Author: findleyr

gopls/internal/regtest/bench/bench_test.go

@@ -33,7 +33,7 @@ func benchmarkOptions(dir string) []RunOption {
 		// Skip logs as they buffer up memory unnaturally.
 		SkipLogs(),
 		// The Debug server only makes sense if running in singleton mode.
-		Modes(Singleton),
+		Modes(Default),
 		// Remove the default timeout. Individual tests should control their
 		// own graceful termination.
 		NoDefaultTimeout(),

gopls/internal/regtest/debug/debug_test.go

@@ -20,7 +20,7 @@ func TestBugNotification(t *testing.T) {
 	// Verify that a properly configured session gets notified of a bug on the
 	// server.
 	WithOptions(
-		Modes(Singleton), // must be in-process to receive the bug report below
+		Modes(Default), // must be in-process to receive the bug report below
 		Settings{"showBugReports": true},
 	).Run(t, "", func(t *testing.T, env *Env) {
 		const desc = "got a bug"

gopls/internal/regtest/diagnostics/diagnostics_test.go

@@ -298,7 +298,7 @@ func Hello() {
 
 	t.Run("without workspace module", func(t *testing.T) {
 		WithOptions(
-			Modes(Singleton),
+			Modes(Default),
 		).Run(t, noMod, func(t *testing.T, env *Env) {
 			env.Await(
 				env.DiagnosticAtRegexp("main.go", `"mod.com/bob"`),
@@ -1678,7 +1678,7 @@ import (
 		WithOptions(
 			InGOPATH(),
 			EnvVars{"GO111MODULE": "off"},
-			Modes(Singleton),
+			Modes(Default),
 		).Run(t, mod, func(t *testing.T, env *Env) {
 			env.Await(
 				env.DiagnosticAtRegexpWithMessage("main.go", `"nosuchpkg"`, `cannot find package "nosuchpkg" in any of`),
@@ -1705,7 +1705,7 @@ package b
 	for _, go111module := range []string{"on", "auto"} {
 		t.Run("GO111MODULE="+go111module, func(t *testing.T) {
 			WithOptions(
-				Modes(Singleton),
+				Modes(Default),
 				EnvVars{"GO111MODULE": go111module},
 			).Run(t, modules, func(t *testing.T, env *Env) {
 				env.OpenFile("a/a.go")
@@ -1722,7 +1722,7 @@ package b
 	// Expect no warning if GO111MODULE=auto in a directory in GOPATH.
 	t.Run("GOPATH_GO111MODULE_auto", func(t *testing.T) {
 		WithOptions(
-			Modes(Singleton),
+			Modes(Default),
 			EnvVars{"GO111MODULE": "auto"},
 			InGOPATH(),
 		).Run(t, modules, func(t *testing.T, env *Env) {
@@ -1784,7 +1784,7 @@ func helloHelper() {}
 `
 	WithOptions(
 		ProxyFiles(proxy),
-		Modes(Singleton),
+		Modes(Default),
 	).Run(t, nested, func(t *testing.T, env *Env) {
 		// Expect a diagnostic in a nested module.
 		env.OpenFile("nested/hello/hello.go")
@@ -1996,7 +1996,7 @@ func Hello() {}
 `
 	WithOptions(
 		Settings{"experimentalUseInvalidMetadata": true},
-		Modes(Singleton),
+		Modes(Default),
 	).Run(t, mod, func(t *testing.T, env *Env) {
 		env.OpenFile("go.mod")
 		env.RegexpReplace("go.mod", "module mod.com", "modul mod.com") // break the go.mod file
@@ -2052,7 +2052,7 @@ func _() {}
 		Settings{"experimentalUseInvalidMetadata": true},
 		// ExperimentalWorkspaceModule has a different failure mode for this
 		// case.
-		Modes(Singleton),
+		Modes(Default),
 	).Run(t, mod, func(t *testing.T, env *Env) {
 		env.Await(
 			OnceMet(

gopls/internal/regtest/misc/semantictokens_test.go

@@ -25,7 +25,7 @@ func main() {}
 
 `
 	WithOptions(
-		Modes(Singleton),
+		Modes(Default),
 		Settings{"allExperiments": true},
 	).Run(t, src, func(t *testing.T, env *Env) {
 		params := &protocol.SemanticTokensParams{}

gopls/internal/regtest/misc/vendor_test.go

@@ -49,7 +49,7 @@ func _() {
 }
 `
 	WithOptions(
-		Modes(Singleton),
+		Modes(Default),
 		ProxyFiles(basicProxy),
 	).Run(t, pkgThatUsesVendoring, func(t *testing.T, env *Env) {
 		env.OpenFile("a/a1.go")

gopls/internal/regtest/modfile/modfile_test.go

@@ -742,7 +742,7 @@ func main() {
 	WithOptions(
 		EnvVars{"GOFLAGS": "-mod=readonly"},
 		ProxyFiles(proxy),
-		Modes(Singleton),
+		Modes(Default),
 	).Run(t, mod, func(t *testing.T, env *Env) {
 		env.OpenFile("main.go")
 		original := env.ReadWorkspaceFile("go.mod")
@@ -922,7 +922,7 @@ func hello() {}
 		// TODO(rFindley) this doesn't work in multi-module workspace mode, because
 		// it keeps around the last parsing modfile. Update this test to also
 		// exercise the workspace module.
-		Modes(Singleton),
+		Modes(Default),
 	).Run(t, mod, func(t *testing.T, env *Env) {
 		env.OpenFile("go.mod")
 		env.Await(env.DoneWithOpen())
@@ -1090,7 +1090,7 @@ func main() {
 `
 	WithOptions(
 		ProxyFiles(workspaceProxy),
-		Modes(Singleton),
+		Modes(Default),
 	).Run(t, mod, func(t *testing.T, env *Env) {
 		env.OpenFile("go.mod")
 		params := &protocol.PublishDiagnosticsParams{}
@@ -1159,7 +1159,7 @@ func main() {
 `
 	WithOptions(
 		ProxyFiles(proxy),
-		Modes(Singleton),
+		Modes(Default),
 	).Run(t, mod, func(t *testing.T, env *Env) {
 		env.OpenFile("main.go")
 		d := &protocol.PublishDiagnosticsParams{}

gopls/internal/regtest/workspace/workspace_test.go

@@ -1205,7 +1205,7 @@ package main
 `
 	WithOptions(
 		EnvVars{"GOPATH": filepath.FromSlash("$SANDBOX_WORKDIR/gopath")},
-		Modes(Singleton),
+		Modes(Default),
 	).Run(t, mod, func(t *testing.T, env *Env) {
 		env.Await(
 			// Confirm that the build configuration is seen as valid,
@@ -1236,7 +1236,7 @@ package main
 func main() {}
 `
 	WithOptions(
-		Modes(Singleton),
+		Modes(Default),
 	).Run(t, nomod, func(t *testing.T, env *Env) {
 		env.OpenFile("a/main.go")
 		env.OpenFile("b/main.go")

gopls/internal/vulncheck/command_test.go

@@ -293,7 +293,7 @@ func runTest(t *testing.T, workspaceData, proxyData string, test func(context.Co
 		t.Fatal(err)
 	}
 
-	cache := cache.New(nil)
+	cache := cache.New(nil, nil, nil)
 	session := cache.NewSession(ctx)
 	options := source.DefaultOptions().Clone()
 	tests.DefaultOptions(options)

internal/lsp/cache/cache.go

@@ -28,23 +28,46 @@ import (
 	"golang.org/x/tools/internal/span"
 )
 
-func New(options func(*source.Options)) *Cache {
+// New Creates a new cache for gopls operation results, using the given file
+// set, shared store, and session options.
+//
+// All of the fset, store and options may be nil, but if store is non-nil so
+// must be fset (and they must always be used together), otherwise it may be
+// possible to get cached data referencing token.Pos values not mapped by the
+// FileSet.
+func New(fset *token.FileSet, store *memoize.Store, options func(*source.Options)) *Cache {
 	index := atomic.AddInt64(&cacheIndex, 1)
+
+	if store != nil && fset == nil {
+		panic("non-nil store with nil fset")
+	}
+	if fset == nil {
+		fset = token.NewFileSet()
+	}
+	if store == nil {
+		store = &memoize.Store{}
+	}
+
 	c := &Cache{
 		id:          strconv.FormatInt(index, 10),
-		fset:        token.NewFileSet(),
+		fset:        fset,
 		options:     options,
+		store:       store,
 		fileContent: map[span.URI]*fileHandle{},
 	}
 	return c
 }
 
 type Cache struct {
-	id      string
-	fset    *token.FileSet
+	id   string
+	fset *token.FileSet
+
+	// TODO(rfindley): it doesn't make sense that cache accepts LSP options, just
+	// so that it can create a session: the cache does not (and should not)
+	// depend on options. Invert this relationship to remove options from Cache.
 	options func(*source.Options)
 
-	store memoize.Store
+	store *memoize.Store
 
 	fileMu      sync.Mutex
 	fileContent map[span.URI]*fileHandle

internal/lsp/cache/check.go

@@ -249,6 +249,16 @@ func computePackageKey(id PackageID, files []source.FileHandle, m *KnownMetadata
 	for _, file := range files {
 		b.WriteString(file.FileIdentity().String())
 	}
+	// Metadata errors are interpreted and memoized on the computed package, so
+	// we must hash them into the key here.
+	//
+	// TODO(rfindley): handle metadata diagnostics independently from
+	// type-checking diagnostics.
+	for _, err := range m.Errors {
+		b.WriteString(err.Msg)
+		b.WriteString(err.Pos)
+		b.WriteRune(rune(err.Kind))
+	}
 	return packageHandleKey(source.HashOf(b.Bytes()))
 }