Added backward compatibility and PR comments

src/server/editorServices.ts

@@ -1429,7 +1429,7 @@ namespace ts.server {
                 this,
                 this.documentRegistry,
                 compilerOptions,
-                /*exceededFilename*/ this.getFilenameForExceededTotalSizeLimitForNonTsFiles(projectFileName, compilerOptions, files, externalFilePropertyReader),
+                /*lastFileExceededProgramSize*/ this.getFilenameForExceededTotalSizeLimitForNonTsFiles(projectFileName, compilerOptions, files, externalFilePropertyReader),
                 options.compileOnSave === undefined ? true : options.compileOnSave);
             project.excludedFiles = excludedFiles;
 
@@ -1495,14 +1495,14 @@ namespace ts.server {
             const cachedDirectoryStructureHost = createCachedDirectoryStructureHost(this.host, this.host.getCurrentDirectory(), this.host.useCaseSensitiveFileNames);
             const { projectOptions, configFileErrors, configFileSpecs } = this.convertConfigFileContentToProjectOptions(configFileName, cachedDirectoryStructureHost);
             this.logger.info(`Opened configuration file ${configFileName}`);
-            const exceededFilename = this.getFilenameForExceededTotalSizeLimitForNonTsFiles(configFileName, projectOptions.compilerOptions, projectOptions.files, fileNamePropertyReader);
+            const lastFileExceededProgramSize = this.getFilenameForExceededTotalSizeLimitForNonTsFiles(configFileName, projectOptions.compilerOptions, projectOptions.files, fileNamePropertyReader);
             const project = new ConfiguredProject(
                 configFileName,
                 this,
                 this.documentRegistry,
                 projectOptions.configHasFilesProperty,
                 projectOptions.compilerOptions,
-                exceededFilename,
+                lastFileExceededProgramSize,
                 projectOptions.compileOnSave === undefined ? false : projectOptions.compileOnSave,
                 cachedDirectoryStructureHost);
 
@@ -1515,7 +1515,7 @@ namespace ts.server {
                 WatchType.ConfigFilePath,
                 project
             );
-            if (!exceededFilename) {
+            if (!lastFileExceededProgramSize) {
                 project.watchWildcards(projectOptions.wildcardDirectories);
             }
 
@@ -1628,9 +1628,9 @@ namespace ts.server {
             // Update the project
             project.configFileSpecs = configFileSpecs;
             project.setProjectErrors(configFileErrors);
-            const exceededFilename = this.getFilenameForExceededTotalSizeLimitForNonTsFiles(project.canonicalConfigFilePath, projectOptions.compilerOptions, projectOptions.files, fileNamePropertyReader);
-            if (exceededFilename) {
-                project.disableLanguageService(exceededFilename);
+            const lastFileExceededProgramSize = this.getFilenameForExceededTotalSizeLimitForNonTsFiles(project.canonicalConfigFilePath, projectOptions.compilerOptions, projectOptions.files, fileNamePropertyReader);
+            if (lastFileExceededProgramSize) {
+                project.disableLanguageService(lastFileExceededProgramSize);
                 project.stopWatchingWildCards();
             }
             else {
@@ -2394,9 +2394,9 @@ namespace ts.server {
                 externalProject.excludedFiles = excludedFiles;
                 if (!tsConfigFiles) {
                     const compilerOptions = convertCompilerOptions(proj.options);
-                    const exceededFilename = this.getFilenameForExceededTotalSizeLimitForNonTsFiles(proj.projectFileName, compilerOptions, proj.rootFiles, externalFilePropertyReader);
-                    if (exceededFilename) {
-                        externalProject.disableLanguageService(exceededFilename);
+                    const lastFileExceededProgramSize = this.getFilenameForExceededTotalSizeLimitForNonTsFiles(proj.projectFileName, compilerOptions, proj.rootFiles, externalFilePropertyReader);
+                    if (lastFileExceededProgramSize) {
+                        externalProject.disableLanguageService(lastFileExceededProgramSize);
                     }
                     else {
                         externalProject.enableLanguageService();

src/server/project.ts

@@ -126,11 +126,13 @@ namespace ts.server {
         private cachedUnresolvedImportsPerFile = new UnresolvedImportsMap();
         private lastCachedUnresolvedImportsList: SortedReadonlyArray<string>;
 
+        /*@internal*/
+        private lastFileExceededProgramSize: string | undefined;
+
         // wrapper over the real language service that will suppress all semantic operations
         protected languageService: LanguageService;
 
         public languageServiceEnabled = true;
-        public exceededFilename: string | undefined;
 
         readonly trace?: (s: string) => void;
         readonly realpath?: (path: string) => string;
@@ -213,7 +215,7 @@ namespace ts.server {
             readonly projectService: ProjectService,
             private documentRegistry: DocumentRegistry,
             hasExplicitListOfFiles: boolean,
-            exceededFilename: string | undefined,
+            lastFileExceededProgramSize: string | undefined,
             private compilerOptions: CompilerOptions,
             public compileOnSaveEnabled: boolean,
             directoryStructureHost: DirectoryStructureHost,
@@ -245,8 +247,8 @@ namespace ts.server {
             // Use the current directory as resolution root only if the project created using current directory string
             this.resolutionCache = createResolutionCache(this, currentDirectory && this.currentDirectory, /*logChangesWhenResolvingModule*/ true);
             this.languageService = createLanguageService(this, this.documentRegistry);
-            if (exceededFilename) {
-                this.disableLanguageService(exceededFilename);
+            if (lastFileExceededProgramSize) {
+                this.disableLanguageService(lastFileExceededProgramSize);
             }
             this.markAsDirty();
         }
@@ -498,16 +500,17 @@ namespace ts.server {
                 return;
             }
             this.languageServiceEnabled = true;
+            this.lastFileExceededProgramSize = undefined;
             this.projectService.onUpdateLanguageServiceStateForProject(this, /*languageServiceEnabled*/ true);
         }
 
-        disableLanguageService(exceededFilename: string) {
+        disableLanguageService(lastFileExceededProgramSize?: string) {
             if (!this.languageServiceEnabled) {
                 return;
             }
             this.languageService.cleanupSemanticCache();
             this.languageServiceEnabled = false;
-            this.exceededFilename = exceededFilename;
+            this.lastFileExceededProgramSize = lastFileExceededProgramSize;
             this.builderState = undefined;
             this.resolutionCache.closeTypeRootsWatch();
             this.projectService.onUpdateLanguageServiceStateForProject(this, /*languageServiceEnabled*/ false);
@@ -1000,7 +1003,8 @@ namespace ts.server {
                 version: this.projectStructureVersion,
                 isInferred: this.projectKind === ProjectKind.Inferred,
                 options: this.getCompilationSettings(),
-                exceededFilename: this.exceededFilename
+                languageServiceDisabled: !this.languageServiceEnabled,
+                lastFileExceededProgramSize: this.lastFileExceededProgramSize
             };
             const updatedFileNames = this.updatedFileNames;
             this.updatedFileNames = undefined;
@@ -1184,7 +1188,7 @@ namespace ts.server {
                 projectService,
                 documentRegistry,
                 /*files*/ undefined,
-                /*exceededFileName*/ undefined,
+                /*lastFileExceededProgramSize*/ undefined,
                 compilerOptions,
                 /*compileOnSaveEnabled*/ false,
                 projectService.host,
@@ -1263,7 +1267,7 @@ namespace ts.server {
             documentRegistry: DocumentRegistry,
             hasExplicitListOfFiles: boolean,
             compilerOptions: CompilerOptions,
-            exceededFilename: string | undefined,
+            lastFileExceededProgramSize: string | undefined,
             public compileOnSaveEnabled: boolean,
             cachedDirectoryStructureHost: CachedDirectoryStructureHost) {
             super(configFileName,
@@ -1271,7 +1275,7 @@ namespace ts.server {
                 projectService,
                 documentRegistry,
                 hasExplicitListOfFiles,
-                exceededFilename,
+                lastFileExceededProgramSize,
                 compilerOptions,
                 compileOnSaveEnabled,
                 cachedDirectoryStructureHost,
@@ -1458,7 +1462,7 @@ namespace ts.server {
             projectService: ProjectService,
             documentRegistry: DocumentRegistry,
             compilerOptions: CompilerOptions,
-            exceededFilename: string | undefined,
+            lastFileExceededProgramSize: string | undefined,
             public compileOnSaveEnabled: boolean,
             projectFilePath?: string) {
             super(externalProjectName,
@@ -1466,7 +1470,7 @@ namespace ts.server {
                 projectService,
                 documentRegistry,
                 /*hasExplicitListOfFiles*/ true,
-                exceededFilename,
+                lastFileExceededProgramSize,
                 compilerOptions,
                 compileOnSaveEnabled,
                 projectService.host,

src/server/protocol.ts

@@ -1104,11 +1104,14 @@ namespace ts.server.protocol {
          * Current set of compiler options for project
          */
         options: ts.CompilerOptions;
-
+        /**
+         * true if project language service is disabled
+         */
+        languageServiceDisabled: boolean;
         /**
          * Filename of the last file analyzed before disabling the language service. undefined, if the language service is enabled.
          */
-        exceededFilename: string | undefined;
+        lastFileExceededProgramSize: string | undefined;
     }
 
     /**