Fixed missing errors in watch mode in webpack5

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## v8.0.10
+* [Fixed missing errors in watch mode in webpack5](https://github.com/TypeStrong/ts-loader/issues/1204) - thanks @appzuka
+
 ## v8.0.9
 * [Fixed build failing when using thread-loader](https://github.com/TypeStrong/ts-loader/pull/1207) - thanks @valerio
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ts-loader",
-  "version": "8.0.9",
+  "version": "8.0.10",
   "description": "TypeScript loader for webpack",
   "main": "index.js",
   "types": "dist",

src/after-compile.ts

@@ -21,8 +21,16 @@ import {
   tsLoaderSource,
 } from './utils';
 
+/**
+ * This returns a function that has options to add assets and also to provide errors to webpack
+ * In webpack 4 we can do both during the afterCompile hook
+ * In webpack 5 only errors should be provided during aftercompile.  Assets should be
+ * emitted during the afterProcessAssets hook
+ */
 export function makeAfterCompile(
   instance: TSInstance,
+  addAssets: boolean,
+  provideErrors: boolean,
   configFilePath: string | undefined
 ) {
   let getCompilerOptionDiagnostics = true;
@@ -39,18 +47,22 @@ export function makeAfterCompile(
     }
 
     if (instance.loaderOptions.transpileOnly) {
-      provideAssetsFromSolutionBuilderHost(instance, compilation);
+      if (addAssets) {
+        provideAssetsFromSolutionBuilderHost(instance, compilation);
+      }
       callback();
       return;
     }
     removeCompilationTSLoaderErrors(compilation, instance.loaderOptions);
 
-    provideCompilerOptionDiagnosticErrorsToWebpack(
-      getCompilerOptionDiagnostics,
-      compilation,
-      instance,
-      configFilePath
-    );
+    if (provideErrors) {
+      provideCompilerOptionDiagnosticErrorsToWebpack(
+        getCompilerOptionDiagnostics,
+        compilation,
+        instance,
+        configFilePath
+      );
+    }
     getCompilerOptionDiagnostics = false;
 
     const modules = determineModules(compilation, instance);
@@ -62,22 +74,25 @@ export function makeAfterCompile(
     checkAllFilesForErrors = false;
 
     const filesWithErrors: TSFiles = new Map();
-    provideErrorsToWebpack(
-      filesToCheckForErrors,
-      filesWithErrors,
-      compilation,
-      modules,
-      instance
-    );
-    provideDeclarationFilesToWebpack(
-      filesToCheckForErrors,
-      instance,
-      compilation
-    );
-    provideTsBuildInfoFilesToWebpack(instance, compilation);
-
-    provideSolutionErrorsToWebpack(compilation, modules, instance);
-    provideAssetsFromSolutionBuilderHost(instance, compilation);
+    if (provideErrors) {
+      provideErrorsToWebpack(
+        filesToCheckForErrors,
+        filesWithErrors,
+        compilation,
+        modules,
+        instance
+      );
+      provideSolutionErrorsToWebpack(compilation, modules, instance);
+    }
+    if (addAssets) {
+      provideDeclarationFilesToWebpack(
+        filesToCheckForErrors,
+        instance,
+        compilation
+      );
+      provideTsBuildInfoFilesToWebpack(instance, compilation);
+      provideAssetsFromSolutionBuilderHost(instance, compilation);
+    }
 
     instance.filesWithErrors = filesWithErrors;
     instance.modifiedFiles = undefined;

src/instances.ts

@@ -302,6 +302,46 @@ function getExistingSolutionBuilderHost(key: FilePathKey) {
   return undefined;
 }
 
+// Adding assets in afterCompile is deprecated in webpack 5 so we
+// need different behavior for webpack4 and 5
+const addAssetHooks = !!webpack.version!.match(/^4.*/)
+  ? (loader: webpack.loader.LoaderContext, instance: TSInstance) => {
+      // add makeAfterCompile with addAssets = true to emit assets and report errors
+      loader._compiler.hooks.afterCompile.tapAsync(
+        'ts-loader',
+        makeAfterCompile(instance, true, true, instance.configFilePath)
+      );
+    }
+  : (loader: webpack.loader.LoaderContext, instance: TSInstance) => {
+      // We must be running under webpack 5+
+
+      // Add makeAfterCompile with addAssets = false to suppress emitting assets
+      // during the afterCompile stage. Errors will be still be reported to webpack
+      loader._compiler.hooks.afterCompile.tapAsync(
+        'ts-loader',
+        makeAfterCompile(instance, false, true, instance.configFilePath)
+      );
+
+      // Emit the assets at the afterProcessAssets stage
+      loader._compilation.hooks.afterProcessAssets.tap(
+        'ts-loader',
+        (_: any) => {
+          makeAfterCompile(
+            instance,
+            true,
+            false,
+            instance.configFilePath
+          )(loader._compilation, () => {
+            return null;
+          });
+        }
+      );
+
+      // It may be better to add assets at the processAssets stage (https://webpack.js.org/api/compilation-hooks/#processassets)
+      // This requires Compilation.PROCESS_ASSETS_STAGE_ADDITIONAL, which does not exist in webpack4
+      // Consider changing this when ts-loader is built using webpack5
+    };
+
 export function initializeInstance(
   loader: webpack.loader.LoaderContext,
   instance: TSInstance
@@ -350,26 +390,7 @@ export function initializeInstance(
     instance.transformers = getCustomTransformers(program);
     // Setup watch run for solution building
     if (instance.solutionBuilderHost) {
-      if (loader._compilation.hooks.afterProcessAssets) {
-        // afterProcessAssets does not exist in webpack4
-        loader._compilation.hooks.afterProcessAssets.tap(
-          'ts-loader',
-          (_: any) => {
-            makeAfterCompile(instance, instance.configFilePath)(
-              loader._compilation,
-              () => {
-                return null;
-              }
-            );
-          }
-        );
-      } else {
-        // adding assets in afterCompile is deprecated in webpack 5
-        loader._compiler.hooks.afterCompile.tapAsync(
-          'ts-loader',
-          makeAfterCompile(instance, instance.configFilePath)
-        );
-      }
+      addAssetHooks(loader, instance);
       loader._compiler.hooks.watchRun.tapAsync(
         'ts-loader',
         makeWatchRun(instance, loader)
@@ -416,26 +437,8 @@ export function initializeInstance(
         instance.languageService!.getProgram()
       );
     }
-    if (loader._compilation.hooks.afterProcessAssets) {
-      // afterProcessAssets does not exist in webpack4
-      loader._compilation.hooks.afterProcessAssets.tap(
-        'ts-loader',
-        (_: any) => {
-          makeAfterCompile(instance, instance.configFilePath)(
-            loader._compilation,
-            () => {
-              return null;
-            }
-          );
-        }
-      );
-    } else {
-      // adding assets in afterCompile is deprecated in webpack 5
-      loader._compiler.hooks.afterCompile.tapAsync(
-        'ts-loader',
-        makeAfterCompile(instance, instance.configFilePath)
-      );
-    }
+
+    addAssetHooks(loader, instance);
 
     loader._compiler.hooks.watchRun.tapAsync(
       'ts-loader',