tests: loader's tests for errors and warnings

.gitignore

@@ -52,3 +52,4 @@ packages/**/*.map
 
 # temporary test files
 test-assets/
+./lib/

packages/webpack-cli/lib/utils/Compiler.js

@@ -80,6 +80,9 @@ class Compiler {
             logger.error(err.stack || err);
             process.exit(1); // eslint-disable-line
         }
+        if (!outputOptions.watch && (stats.hasErrors() || stats.hasWarnings())) {
+            process.exitCode = 1;
+        }
         if (outputOptions.json) {
             process.stdout.write(JSON.stringify(stats.toJson(outputOptions), null, 2) + '\n');
         } else if (stats.hash !== lastHash) {
@@ -93,9 +96,6 @@ class Compiler {
             }
             return this.generateOutput(outputOptions, stats, statsErrors, processingMessageBuffer);
         }
-        if (!outputOptions.watch && stats.hasErrors()) {
-            process.exitCode = 2;
-        }
     }
 
     async invokeCompilerInstance(lastHash, options, outputOptions, processingMessageBuffer) {

test/loader/error-test/loader-error.test.js

@@ -0,0 +1,15 @@
+'use strict';
+
+// eslint-disable-next-line node/no-unpublished-require
+const { run } = require('../../utils/test-utils');
+
+describe('loader error regression test for #1581', () => {
+    it(`should not ignore loader's error produce a failing build`, () => {
+        // Ignoring assertion on stderr because ts-loader is producing depreciation warnings
+        // with [email protected] -> https://github.com/TypeStrong/ts-loader/issues/1169
+        const { stdout, exitCode } = run(__dirname, [], false);
+        expect(exitCode).not.toEqual(0);
+        expect(stdout).toContain('[1 error]');
+        expect(stdout).toContain(`Cannot assign to 'foobar' because it is a constant`);
+    });
+});

test/loader/error-test/package.json

@@ -0,0 +1,6 @@
+{
+  "dependencies": {
+    "ts-loader": "^7.0.5",
+    "typescript": "^3.9.3"
+  }
+}

test/loader/error-test/src/index.ts

@@ -0,0 +1,4 @@
+const foobar = 'foobar';
+// eslint-disable-next-line no-const-assign
+foobar = 'barbaz'; // Error!
+console.log(foobar);

test/loader/error-test/webpack.config.js

@@ -0,0 +1,25 @@
+const path = require('path');
+
+module.exports = {
+    mode: 'development',
+
+    entry: {
+        bundle: './src/index.ts',
+    },
+
+    output: {
+        path: path.resolve(__dirname, 'dist'),
+        filename: '[name].js',
+    },
+
+    module: {
+        rules: [
+            {
+                test: /.(ts|tsx)?$/,
+                loader: 'ts-loader',
+                include: [path.resolve(__dirname, 'src')],
+                exclude: [/node_modules/],
+            },
+        ],
+    },
+};

test/loader/warning-test/loader-warning.test.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const { run } = require('../../utils/test-utils');
+
+describe('loader warning test', () => {
+    it(`should not ignore loader's warning and exit with a non zero exit code`, () => {
+        const { stdout, exitCode } = run(__dirname, [], false);
+
+        expect(stdout).toContain('[1 warning]');
+        expect(stdout).toContain('This is a warning');
+        expect(exitCode).not.toEqual(0);
+    });
+});

test/loader/warning-test/my-loader.js

@@ -0,0 +1,5 @@
+module.exports = function loader(source) {
+    const { emitWarning } = this;
+    emitWarning('This is a warning');
+    return source;
+};

test/loader/warning-test/src/main.js

@@ -0,0 +1,2 @@
+require('../my-loader');
+console.log('loader warning test');

test/loader/warning-test/webpack.config.js

@@ -0,0 +1,30 @@
+const path = require('path');
+
+module.exports = {
+    mode: 'development',
+
+    entry: {
+        bundle: './src/main.js',
+    },
+
+    output: {
+        path: path.resolve(__dirname, 'dist'),
+        filename: '[name].js',
+    },
+
+    module: {
+        rules: [
+            {
+                test: /.(js|jsx)?$/,
+                loader: 'my-loader',
+                include: [path.resolve(__dirname, 'src')],
+                exclude: [/node_modules/],
+            },
+        ],
+    },
+    resolveLoader: {
+        alias: {
+            'my-loader': require.resolve('./my-loader'),
+        },
+    },
+};