internal/lsp: enable template processing and add templateFiles option

Move template processing out of experimental and enable it. Users
can set the option 'templateSupport' to false to disable it.
Also, add a new flag 'templateExtensions', defaulting to ['tmpl','gotmpl']
to let the user provide a list of extensions of files
to be considered as template files.

Change-Id: I724387738c1632256999cda304d6cf9fa48ed91d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/362241
Run-TryBot: Peter Weinberger <pjw@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Peter Weinberger <pjw@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>

gopls/doc/settings.md

@@ -72,6 +72,20 @@ Include only project_a, but not node_modules inside it: `-`, `+project_a`, `-pro
 
 Default: `["-node_modules"]`.
 
+#### **templateSupport** *bool*
+
+templateSupport can be used to turn off support for template files.
+
+Default: `true`.
+
+#### **templateExtensions** *[]string*
+
+templateExtensions gives the extensions of file names that are treateed
+as template files. (The extension
+is the part of the file name after the final dot.)
+
+Default: `["tmpl","gotmpl"]`.
+
 #### **memoryMode** *enum*
 
 **This setting is experimental and may be deleted.**
@@ -112,15 +126,6 @@ for multi-module workspaces.
 
 Default: `false`.
 
-#### **experimentalTemplateSupport** *bool*
-
-**This setting is experimental and may be deleted.**
-
-experimentalTemplateSupport opts into the experimental support
-for template files.
-
-Default: `false`.
-
 #### **experimentalPackageCacheKey** *bool*
 
 **This setting is experimental and may be deleted.**

internal/lsp/cache/snapshot.go

@@ -159,7 +159,7 @@ func (s *snapshot) ModFiles() []span.URI {
 }
 
 func (s *snapshot) Templates() map[span.URI]source.VersionedFileHandle {
-	if !s.view.Options().ExperimentalTemplateSupport {
+	if !s.view.Options().TemplateSupport {
 		return nil
 	}
 
@@ -783,12 +783,15 @@ func (s *snapshot) getWorkspacePkgPath(id PackageID) PackagePath {
 const fileExtensions = "go,mod,sum,work,tmpl"
 
 func (s *snapshot) fileWatchingGlobPatterns(ctx context.Context) map[string]struct{} {
+	extensions := fileExtensions
+	for _, ext := range s.View().Options().TemplateExtensions {
+		extensions += "," + ext
+	}
 	// Work-around microsoft/vscode#100870 by making sure that we are,
 	// at least, watching the user's entire workspace. This will still be
 	// applied to every folder in the workspace.
 	patterns := map[string]struct{}{
-		fmt.Sprintf("**/*.{%s}", fileExtensions): {},
-		"**/*.*tmpl":                             {},
+		fmt.Sprintf("**/*.{%s}", extensions): {},
 	}
 	dirs := s.workspace.dirs(ctx, s)
 	for _, dir := range dirs {
@@ -802,7 +805,7 @@ func (s *snapshot) fileWatchingGlobPatterns(ctx context.Context) map[string]stru
 		// TODO(rstambler): If microsoft/vscode#3025 is resolved before
 		// microsoft/vscode#101042, we will need a work-around for Windows
 		// drive letter casing.
-		patterns[fmt.Sprintf("%s/**/*.{%s}", dirName, fileExtensions)] = struct{}{}
+		patterns[fmt.Sprintf("%s/**/*.{%s}", dirName, extensions)] = struct{}{}
 	}
 
 	// Some clients do not send notifications for changes to directories that

internal/lsp/cache/view.go

@@ -332,10 +332,25 @@ func (s *snapshot) RunProcessEnvFunc(ctx context.Context, fn func(*imports.Optio
 	return s.view.importsState.runProcessEnvFunc(ctx, s, fn)
 }
 
+// separated out from its sole use in locateTemplatFiles for testability
+func fileHasExtension(path string, suffixes []string) bool {
+	ext := filepath.Ext(path)
+	if ext != "" && ext[0] == '.' {
+		ext = ext[1:]
+	}
+	for _, s := range suffixes {
+		if s != "" && ext == s {
+			return true
+		}
+	}
+	return false
+}
+
 func (s *snapshot) locateTemplateFiles(ctx context.Context) {
-	if !s.view.Options().ExperimentalTemplateSupport {
+	if !s.view.Options().TemplateSupport {
 		return
 	}
+	suffixes := s.view.Options().TemplateExtensions
 	dir := s.workspace.root.Filename()
 	searched := 0
 	// Change to WalkDir when we move up to 1.16
@@ -343,7 +358,7 @@ func (s *snapshot) locateTemplateFiles(ctx context.Context) {
 		if err != nil {
 			return err
 		}
-		if strings.HasSuffix(filepath.Ext(path), "tmpl") && !pathExcludedByFilter(path, dir, s.view.gomodcache, s.view.options) &&
+		if fileHasExtension(path, suffixes) && !pathExcludedByFilter(path, dir, s.view.gomodcache, s.view.options) &&
 			!fi.IsDir() {
 			k := span.URIFromPath(path)
 			fh, err := s.GetVersionedFile(ctx, k)

internal/lsp/cache/view_test.go

@@ -172,3 +172,44 @@ func TestFilters(t *testing.T) {
 		}
 	}
 }
+
+func TestSuffixes(t *testing.T) {
+	type file struct {
+		path string
+		want bool
+	}
+	type cases struct {
+		option []string
+		files  []file
+	}
+	tests := []cases{
+		{[]string{"tmpl", "gotmpl"}, []file{ // default
+			{"foo", false},
+			{"foo.tmpl", true},
+			{"foo.gotmpl", true},
+			{"tmpl", false},
+			{"tmpl.go", false}},
+		},
+		{[]string{"tmpl", "gotmpl", "html", "gohtml"}, []file{
+			{"foo.gotmpl", true},
+			{"foo.html", true},
+			{"foo.gohtml", true},
+			{"html", false}},
+		},
+		{[]string{"tmpl", "gotmpl", ""}, []file{ // possible user mistake
+			{"foo.gotmpl", true},
+			{"foo.go", false},
+			{"foo", false}},
+		},
+	}
+	for _, a := range tests {
+		suffixes := a.option
+		for _, b := range a.files {
+			got := fileHasExtension(b.path, suffixes)
+			if got != b.want {
+				t.Errorf("got %v, want %v, option %q, file %q (%+v)",
+					got, b.want, a.option, b.path, b)
+			}
+		}
+	}
+}

internal/lsp/source/api_json.go

@@ -44,6 +44,32 @@ var GeneratedAPIJSON = &APIJSON{
 				Status:     "",
 				Hierarchy:  "build",
 			},
+			{
+				Name: "templateSupport",
+				Type: "bool",
+				Doc:  "templateSupport can be used to turn off support for template files.\n",
+				EnumKeys: EnumKeys{
+					ValueType: "",
+					Keys:      nil,
+				},
+				EnumValues: nil,
+				Default:    "true",
+				Status:     "",
+				Hierarchy:  "build",
+			},
+			{
+				Name: "templateExtensions",
+				Type: "[]string",
+				Doc:  "templateExtensions gives the extensions of file names that are treateed\nas template files. (The extension\nis the part of the file name after the final dot.)\n",
+				EnumKeys: EnumKeys{
+					ValueType: "",
+					Keys:      nil,
+				},
+				EnumValues: nil,
+				Default:    "[\"tmpl\",\"gotmpl\"]",
+				Status:     "",
+				Hierarchy:  "build",
+			},
 			{
 				Name: "memoryMode",
 				Type: "enum",
@@ -92,19 +118,6 @@ var GeneratedAPIJSON = &APIJSON{
 				Status:     "experimental",
 				Hierarchy:  "build",
 			},
-			{
-				Name: "experimentalTemplateSupport",
-				Type: "bool",
-				Doc:  "experimentalTemplateSupport opts into the experimental support\nfor template files.\n",
-				EnumKeys: EnumKeys{
-					ValueType: "",
-					Keys:      nil,
-				},
-				EnumValues: nil,
-				Default:    "false",
-				Status:     "experimental",
-				Hierarchy:  "build",
-			},
 			{
 				Name: "experimentalPackageCacheKey",
 				Type: "bool",

internal/lsp/source/options.go

@@ -114,6 +114,8 @@ func DefaultOptions() *Options {
 					ExperimentalPackageCacheKey: true,
 					MemoryMode:                  ModeNormal,
 					DirectoryFilters:            []string{"-node_modules"},
+					TemplateSupport:             true,
+					TemplateExtensions:          []string{"tmpl", "gotmpl"},
 				},
 				UIOptions: UIOptions{
 					DiagnosticOptions: DiagnosticOptions{
@@ -231,6 +233,14 @@ type BuildOptions struct {
 	// Include only project_a, but not node_modules inside it: `-`, `+project_a`, `-project_a/node_modules`
 	DirectoryFilters []string
 
+	// TemplateSupport can be used to turn off support for template files.
+	TemplateSupport bool
+
+	// TemplateExtensions gives the extensions of file names that are treateed
+	// as template files. (The extension
+	// is the part of the file name after the final dot.)
+	TemplateExtensions []string
+
 	// MemoryMode controls the tradeoff `gopls` makes between memory usage and
 	// correctness.
 	//
@@ -249,10 +259,6 @@ type BuildOptions struct {
 	// for multi-module workspaces.
 	ExperimentalWorkspaceModule bool `status:"experimental"`
 
-	// ExperimentalTemplateSupport opts into the experimental support
-	// for template files.
-	ExperimentalTemplateSupport bool `status:"experimental"`
-
 	// ExperimentalPackageCacheKey controls whether to use a coarser cache key
 	// for package type information to increase cache hits. This setting removes
 	// the user's environment, build flags, and working directory from the cache
@@ -747,7 +753,6 @@ func (o *Options) AddStaticcheckAnalyzer(a *analysis.Analyzer, enabled bool, sev
 func (o *Options) EnableAllExperiments() {
 	o.SemanticTokens = true
 	o.ExperimentalPostfixCompletions = true
-	o.ExperimentalTemplateSupport = true
 	o.ExperimentalUseInvalidMetadata = true
 	o.ExperimentalWatchedFileDelay = 50 * time.Millisecond
 }
@@ -935,8 +940,21 @@ func (o *Options) set(name string, value interface{}, seen map[string]struct{})
 	case "experimentalWorkspaceModule":
 		result.setBool(&o.ExperimentalWorkspaceModule)
 
-	case "experimentalTemplateSupport":
-		result.setBool(&o.ExperimentalTemplateSupport)
+	case "experimentalTemplateSupport", // remove after June 2022
+		"templateSupport":
+		if name == "experimentalTemplateSupport" {
+			result.State = OptionDeprecated
+			result.Replacement = "templateSupport"
+		}
+		result.setBool(&o.TemplateSupport)
+
+	case "templateExtensions":
+		iexts, ok := value.([]string)
+		if !ok {
+			result.errorf("invalid type %T, expect []string", value)
+			break
+		}
+		o.TemplateExtensions = iexts
 
 	case "experimentalDiagnosticsDelay", "diagnosticsDelay":
 		if name == "experimentalDiagnosticsDelay" {

internal/lsp/template/implementations.go

@@ -66,7 +66,7 @@ func Diagnose(f source.VersionedFileHandle) []*source.Diagnostic {
 }
 
 func skipTemplates(s source.Snapshot) bool {
-	return !s.View().Options().ExperimentalTemplateSupport
+	return !s.View().Options().TemplateSupport
 }
 
 // Definition finds the definitions of the symbol at loc. It