feat(watch): show file-level error summary in watch mode

This change updates the watch mode error reporting to include a detailed
summary of errors per file, similar to non-watch mode.
It uses 'getErrorSummaryText' to generate the summary and introduces
a new diagnostic message '_0_Watching_for_file_changes' to display it
alongside the watch status.

Verification:
- Verified manually with reproduction case (single error and zero errors).
- Ran existing 'tscWatch' tests and updated baselines for 213 scenarios.
- All 454 watch mode tests passed.

Author: suvendukungfu

src/compiler/diagnosticMessages.json

@@ -1539,7 +1539,6 @@
         "category": "Error",
         "code": 1464
     },
-
     "The 'import.meta' meta-property is not allowed in files which will build into CommonJS output.": {
         "category": "Error",
         "code": 1470
@@ -1860,7 +1859,6 @@
         "category": "Message",
         "code": 1549
     },
-
     "The types of '{0}' are incompatible between these types.": {
         "category": "Error",
         "code": 2200
@@ -1901,7 +1899,6 @@
         "category": "Error",
         "code": 2208
     },
-
     "The project root is ambiguous, but is required to resolve export map entry '{0}' in file '{1}'. Supply the `rootDir` compiler option to disambiguate.": {
         "category": "Error",
         "code": 2209
@@ -1918,7 +1915,6 @@
         "category": "Message",
         "code": 2212
     },
-
     "Duplicate identifier '{0}'.": {
         "category": "Error",
         "code": 2300
@@ -2899,7 +2895,6 @@
         "category": "Error",
         "code": 2568
     },
-
     "Could not find name '{0}'. Did you mean '{1}'?": {
         "category": "Error",
         "code": 2570
@@ -3140,7 +3135,6 @@
         "category": "Error",
         "code": 2639
     },
-
     "Cannot augment module '{0}' with value exports because it resolves to a non-module entity.": {
         "category": "Error",
         "code": 2649
@@ -4022,7 +4016,6 @@
         "category": "Error",
         "code": 2882
     },
-
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
         "code": 4000
@@ -4467,7 +4460,6 @@
         "category": "Error",
         "code": 4128
     },
-
     "The current host does not support the '{0}' option.": {
         "category": "Error",
         "code": 5001
@@ -4744,7 +4736,6 @@
         "category": "Error",
         "code": 5112
     },
-
     "Generates a sourcemap for each corresponding '.d.ts' file.": {
         "category": "Message",
         "code": 6000
@@ -5401,6 +5392,10 @@
         "category": "Message",
         "code": 6194
     },
+    "{0} Watching for file changes.": {
+        "category": "Message",
+        "code": 6499
+    },
     "Resolve 'keyof' to string valued property names only (no numbers or symbols).": {
         "category": "Message",
         "code": 6195
@@ -5688,7 +5683,6 @@
         "category": "Error",
         "code": 6266
     },
-
     "Directory '{0}' has no containing package.json scope. Imports will not resolve.": {
         "category": "Message",
         "code": 6270
@@ -5781,7 +5775,6 @@
         "category": "Message",
         "code": 6294
     },
-
     "Enable project compilation": {
         "category": "Message",
         "code": 6302
@@ -6064,7 +6057,6 @@
         "category": "Message",
         "code": 6421
     },
-
     "The expected type comes from property '{0}' which is declared here on type '{1}'": {
         "category": "Message",
         "code": 6500
@@ -6593,7 +6585,6 @@
         "category": "Message",
         "code": 6809
     },
-
     "one of:": {
         "category": "Message",
         "code": 6900
@@ -6610,7 +6601,6 @@
         "category": "Message",
         "code": 6903
     },
-
     "`true`, unless `strict` is `false`": {
         "category": "Message",
         "code": 6905
@@ -6723,7 +6713,6 @@
         "category": "Message",
         "code": 6932
     },
-
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005
@@ -6946,7 +6935,6 @@
         "category": "Error",
         "code": 7061
     },
-
     "You cannot rename this element.": {
         "category": "Error",
         "code": 8000
@@ -7091,7 +7079,6 @@
         "category": "Error",
         "code": 8039
     },
-
     "Declaration emit for this file requires using private name '{0}'. An explicit type annotation may unblock declaration emit.": {
         "category": "Error",
         "code": 9005
@@ -7324,7 +7311,6 @@
         "category": "Error",
         "code": 18003
     },
-
     "File is a CommonJS module; it may be converted to an ES module.": {
         "category": "Suggestion",
         "code": 80001
@@ -7365,7 +7351,6 @@
         "category": "Suggestion",
         "code": 80010
     },
-
     "Add missing 'super()' call": {
         "category": "Message",
         "code": 90001
@@ -7586,7 +7571,6 @@
         "category": "Message",
         "code": 90071
     },
-
     "Convert function to an ES2015 class": {
         "category": "Message",
         "code": 95001
@@ -8355,7 +8339,6 @@
         "category": "Message",
         "code": 95197
     },
-
     "No value exists in scope for the shorthand property '{0}'. Either declare one or provide an initializer.": {
         "category": "Error",
         "code": 18004
@@ -8552,4 +8535,4 @@
         "category": "Error",
         "code": 18061
     }
-}
+}

src/compiler/watch.ts

@@ -263,6 +263,14 @@ export function getWatchErrorSummaryDiagnosticMessage(errorCount: number): Diagn
         Diagnostics.Found_0_errors_Watching_for_file_changes;
 }
 
+export function getWatchErrorSummaryDiagnostic(errorCount: number, filesInError: (ReportFileInError | undefined)[], newLine: string, host: HasCurrentDirectory, options: CompilerOptions): Diagnostic {
+    if (errorCount === 0) {
+        return createCompilerDiagnostic(Diagnostics.Found_0_errors_Watching_for_file_changes, 0);
+    }
+    const errorSummary = getErrorSummaryText(errorCount, filesInError, newLine, host);
+    return createCompilerDiagnostic(Diagnostics._0_Watching_for_file_changes, errorSummary);
+}
+
 function prettyPathForFileError(error: ReportFileInError, cwd: string) {
     const line = formatColorAndReset(":" + error.line, ForegroundColorEscapeSequences.Grey);
     if (pathIsAbsolute(error.fileName) && pathIsAbsolute(cwd)) {
@@ -293,7 +301,7 @@ export function getErrorSummaryText(
     else {
         messageAndArgs = distinctFileNamesWithLines.length === 0 ? [Diagnostics.Found_0_errors, errorCount] :
             distinctFileNamesWithLines.length === 1 ? [Diagnostics.Found_0_errors_in_the_same_file_starting_at_Colon_1, errorCount, firstFileReference] :
-            [Diagnostics.Found_0_errors_in_1_files, errorCount, distinctFileNamesWithLines.length];
+                [Diagnostics.Found_0_errors_in_1_files, errorCount, distinctFileNamesWithLines.length];
     }
 
     const d = createCompilerDiagnostic(...messageAndArgs);
@@ -524,8 +532,8 @@ export function fileIncludeReasonToDiagnostics(program: Program, reason: FileInc
                         Diagnostics.Output_from_referenced_project_0_included_because_1_specified :
                         Diagnostics.Source_from_referenced_project_0_included_because_1_specified :
                     isOutput ?
-                    Diagnostics.Output_from_referenced_project_0_included_because_module_is_specified_as_none :
-                    Diagnostics.Source_from_referenced_project_0_included_because_module_is_specified_as_none,
+                        Diagnostics.Output_from_referenced_project_0_included_because_module_is_specified_as_none :
+                        Diagnostics.Source_from_referenced_project_0_included_because_module_is_specified_as_none,
                 toFileName(referencedResolvedRef.sourceFile.fileName, fileNameConvertor),
                 options.outFile ? "--outFile" : "--out",
             );
@@ -535,8 +543,8 @@ export function fileIncludeReasonToDiagnostics(program: Program, reason: FileInc
                     [Diagnostics.Entry_point_of_type_library_0_specified_in_compilerOptions_with_packageId_1, reason.typeReference, packageIdToString(reason.packageId)] :
                     [Diagnostics.Entry_point_of_type_library_0_specified_in_compilerOptions, reason.typeReference] :
                 reason.packageId ?
-                [Diagnostics.Entry_point_for_implicit_type_library_0_with_packageId_1, reason.typeReference, packageIdToString(reason.packageId)] :
-                [Diagnostics.Entry_point_for_implicit_type_library_0, reason.typeReference];
+                    [Diagnostics.Entry_point_for_implicit_type_library_0_with_packageId_1, reason.typeReference, packageIdToString(reason.packageId)] :
+                    [Diagnostics.Entry_point_for_implicit_type_library_0, reason.typeReference];
 
             return chainDiagnosticMessages(/*details*/ undefined, ...messageAndArgs);
         }
@@ -880,9 +888,9 @@ function createWatchCompilerHost<T extends BuilderProgram = EmitAndSemanticDiagn
             builderProgram,
             reportDiagnostic,
             write,
-            errorCount =>
+            (errorCount, filesInError) =>
                 result.onWatchStatusChange!(
-                    createCompilerDiagnostic(getWatchErrorSummaryDiagnosticMessage(errorCount), errorCount),
+                    getWatchErrorSummaryDiagnostic(errorCount, filesInError, newLine, result, compilerOptions),
                     newLine,
                     compilerOptions,
                     errorCount,

tests/baselines/reference/tscWatch/emit/emit-for-configured-projects/should-always-return-the-file-itself-if-'--out'-or-'--outFile'-is-specified.js

@@ -53,7 +53,10 @@ Output::
 4     "outFile": "/home/src/projects/a/b/out.js"
       ~~~~~~~~~
 
-[HH:MM:SS AM] Found 2 errors. Watching for file changes.
+[HH:MM:SS AM] 
+Found 2 errors in the same file, starting at: tsconfig.json:3
+
+ Watching for file changes.
 
 
 
@@ -186,7 +189,10 @@ Output::
 4     "outFile": "/home/src/projects/a/b/out.js"
       ~~~~~~~~~
 
-[HH:MM:SS AM] Found 2 errors. Watching for file changes.
+[HH:MM:SS AM] 
+Found 2 errors in the same file, starting at: tsconfig.json:3
+
+ Watching for file changes.
 
 
 

tests/baselines/reference/tscWatch/emit/emit-for-configured-projects/should-be-up-to-date-with-the-reference-map-changes.js

@@ -149,7 +149,10 @@ Output::
 1 export let y = Foo();
                  ~~~
 
-[HH:MM:SS AM] Found 1 error. Watching for file changes.
+[HH:MM:SS AM] 
+Found 1 error in file1Consumer1.ts:1
+
+ Watching for file changes.
 
 
 
@@ -211,7 +214,10 @@ Output::
 1 export let y = Foo();
                  ~~~
 
-[HH:MM:SS AM] Found 1 error. Watching for file changes.
+[HH:MM:SS AM] 
+Found 1 error in file1Consumer1.ts:1
+
+ Watching for file changes.
 
 
 
@@ -346,7 +352,14 @@ Output::
 1 export let y = Foo();
                  ~~~
 
-[HH:MM:SS AM] Found 3 errors. Watching for file changes.
+[HH:MM:SS AM] 
+Found 3 errors in 3 files.
+
+Errors  Files
+     1  file1Consumer1.ts:1
+     1  file1Consumer2.ts:1
+     1  moduleFile1.ts:1
+ Watching for file changes.
 
 
 

tests/baselines/reference/tscWatch/emit/emit-for-configured-projects/should-detect-non-existing-code-file.js

@@ -37,7 +37,10 @@ Output::
 2 export var x = Foo();
                  ~~~
 
-[HH:MM:SS AM] Found 2 errors. Watching for file changes.
+[HH:MM:SS AM] 
+Found 2 errors in the same file, starting at: referenceFile1.ts:1
+
+ Watching for file changes.
 
 
 
@@ -122,7 +125,10 @@ Output::
 2 export var x = Foo();export var yy = Foo();
                                        ~~~
 
-[HH:MM:SS AM] Found 3 errors. Watching for file changes.
+[HH:MM:SS AM] 
+Found 3 errors in the same file, starting at: referenceFile1.ts:1
+
+ Watching for file changes.
 
 
 
@@ -199,7 +205,10 @@ Output::
 2 export var x = Foo();export var yy = Foo();
                                        ~~~
 
-[HH:MM:SS AM] Found 2 errors. Watching for file changes.
+[HH:MM:SS AM] 
+Found 2 errors in the same file, starting at: referenceFile1.ts:2
+
+ Watching for file changes.
 
 
 

tests/baselines/reference/tscWatch/emit/emit-for-configured-projects/should-detect-removed-code-file.js

@@ -35,7 +35,10 @@ Output::
 2 export var x = Foo();
                  ~~~
 
-[HH:MM:SS AM] Found 1 error. Watching for file changes.
+[HH:MM:SS AM] 
+Found 1 error in referenceFile1.ts:2
+
+ Watching for file changes.
 
 
 
@@ -119,7 +122,10 @@ Output::
 2 export var x = Foo();
                  ~~~
 
-[HH:MM:SS AM] Found 2 errors. Watching for file changes.
+[HH:MM:SS AM] 
+Found 2 errors in the same file, starting at: referenceFile1.ts:1
+
+ Watching for file changes.