Added errorCount to WatchStatusReporter to detect 2 or more errors

src/compiler/watch.ts

@@ -372,7 +372,8 @@ namespace ts {
                 errorCount => result.onWatchStatusChange!(
                     createCompilerDiagnostic(getWatchErrorSummaryDiagnosticMessage(errorCount), errorCount),
                     newLine,
-                    compilerOptions
+                    compilerOptions,
+                    errorCount
                 )
             );
         };
@@ -480,14 +481,14 @@ namespace ts {
         return createProgram(rootNames, options, host, oldProgram, configFileParsingDiagnostics, projectReferences);
     }
 
-    export type WatchStatusReporter = (diagnostic: Diagnostic, newLine: string, options: CompilerOptions) => void;
+    export type WatchStatusReporter = (diagnostic: Diagnostic, newLine: string, options: CompilerOptions, errorCount?: number) => void;
     /** Create the program with rootNames and options, if they are undefined, oldProgram and new configFile diagnostics create new program */
     export type CreateProgram<T extends BuilderProgram> = (rootNames: ReadonlyArray<string> | undefined, options: CompilerOptions | undefined, host?: CompilerHost, oldProgram?: T, configFileParsingDiagnostics?: ReadonlyArray<Diagnostic>, projectReferences?: ReadonlyArray<ProjectReference> | undefined) => T;
 
     /** Host that has watch functionality used in --watch mode */
     export interface WatchHost {
         /** If provided, called with Diagnostic message that informs about change in watch status */
-        onWatchStatusChange?(diagnostic: Diagnostic, newLine: string, options: CompilerOptions): void;
+        onWatchStatusChange?(diagnostic: Diagnostic, newLine: string, options: CompilerOptions, errorCount?: number): void;
 
         /** Used to watch changes in source files, missing files needed to update the program or config file */
         watchFile(path: string, callback: FileWatcherCallback, pollingInterval?: number): FileWatcher;

src/testRunner/unittests/tscWatch/watchApi.ts

@@ -37,4 +37,32 @@ namespace ts.tscWatch {
             checkProgramActualFiles(program, [mainFile.path, libFile.path, settingsJson.path]);
         });
     });
+
+    describe("unittests:: tsc-watch:: watchAPI:: tsc-watch expose error count to watch status reporter", () => {
+        const projectRoot = "/user/username/projects/project";
+        const configFileJson: any = {
+            compilerOptions: { module: "commonjs" },
+            files: ["index.ts"]
+        };
+        const config: File = {
+            path: `${projectRoot}/tsconfig.json`,
+            content: JSON.stringify(configFileJson)
+        };
+        const mainFile: File = {
+            path: `${projectRoot}/index.ts`,
+            content: "let compiler = new Compiler(); for (let i = 0; j < 5; i++) {}"
+        };
+
+        it("verify that the error count is correctly passed down to the watch status reporter", () => {
+            const files = [libFile, mainFile, config];
+            const host = createWatchedSystem(files, { currentDirectory: projectRoot });
+            let watchedErrorCount;
+            const reportWatchStatus: WatchStatusReporter = (_, __, ___, errorCount) => {
+                watchedErrorCount = errorCount;
+            };
+            const compilerHost = createWatchCompilerHostOfConfigFile(config.path, {}, host, /*createProgram*/ undefined, /*reportDiagnostic*/ undefined, reportWatchStatus);
+            createWatchProgram(compilerHost);
+            assert.equal(watchedErrorCount, 2, "The error count was expected to be 2 for the file change");
+        });
+    });
 }

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -4491,13 +4491,13 @@ declare namespace ts {
         createProgram?: CreateProgram<T>;
     }
     function createIncrementalProgram<T extends BuilderProgram = EmitAndSemanticDiagnosticsBuilderProgram>({ rootNames, options, configFileParsingDiagnostics, projectReferences, host, createProgram }: IncrementalProgramOptions<T>): T;
-    type WatchStatusReporter = (diagnostic: Diagnostic, newLine: string, options: CompilerOptions) => void;
+    type WatchStatusReporter = (diagnostic: Diagnostic, newLine: string, options: CompilerOptions, errorCount?: number) => void;
     /** Create the program with rootNames and options, if they are undefined, oldProgram and new configFile diagnostics create new program */
     type CreateProgram<T extends BuilderProgram> = (rootNames: ReadonlyArray<string> | undefined, options: CompilerOptions | undefined, host?: CompilerHost, oldProgram?: T, configFileParsingDiagnostics?: ReadonlyArray<Diagnostic>, projectReferences?: ReadonlyArray<ProjectReference> | undefined) => T;
     /** Host that has watch functionality used in --watch mode */
     interface WatchHost {
         /** If provided, called with Diagnostic message that informs about change in watch status */
-        onWatchStatusChange?(diagnostic: Diagnostic, newLine: string, options: CompilerOptions): void;
+        onWatchStatusChange?(diagnostic: Diagnostic, newLine: string, options: CompilerOptions, errorCount?: number): void;
         /** Used to watch changes in source files, missing files needed to update the program or config file */
         watchFile(path: string, callback: FileWatcherCallback, pollingInterval?: number): FileWatcher;
         /** Used to watch resolved module's failed lookup locations, config file specs, type roots where auto type reference directives are added */

tests/baselines/reference/api/typescript.d.ts

@@ -4491,13 +4491,13 @@ declare namespace ts {
         createProgram?: CreateProgram<T>;
     }
     function createIncrementalProgram<T extends BuilderProgram = EmitAndSemanticDiagnosticsBuilderProgram>({ rootNames, options, configFileParsingDiagnostics, projectReferences, host, createProgram }: IncrementalProgramOptions<T>): T;
-    type WatchStatusReporter = (diagnostic: Diagnostic, newLine: string, options: CompilerOptions) => void;
+    type WatchStatusReporter = (diagnostic: Diagnostic, newLine: string, options: CompilerOptions, errorCount?: number) => void;
     /** Create the program with rootNames and options, if they are undefined, oldProgram and new configFile diagnostics create new program */
     type CreateProgram<T extends BuilderProgram> = (rootNames: ReadonlyArray<string> | undefined, options: CompilerOptions | undefined, host?: CompilerHost, oldProgram?: T, configFileParsingDiagnostics?: ReadonlyArray<Diagnostic>, projectReferences?: ReadonlyArray<ProjectReference> | undefined) => T;
     /** Host that has watch functionality used in --watch mode */
     interface WatchHost {
         /** If provided, called with Diagnostic message that informs about change in watch status */
-        onWatchStatusChange?(diagnostic: Diagnostic, newLine: string, options: CompilerOptions): void;
+        onWatchStatusChange?(diagnostic: Diagnostic, newLine: string, options: CompilerOptions, errorCount?: number): void;
         /** Used to watch changes in source files, missing files needed to update the program or config file */
         watchFile(path: string, callback: FileWatcherCallback, pollingInterval?: number): FileWatcher;
         /** Used to watch resolved module's failed lookup locations, config file specs, type roots where auto type reference directives are added */