No errors plugin deprecate (webpack#3570)

* added deprecation with unit test
* added deprecation for NoErrorsPlugin in favor of NoEmitOnErrorsPlugin with unit test
* add new NoEmitOnErrorsPlugin to exports and add an extra unit test to check that there is no warning when using it
* added test for NoEmitOnErrorsPlugin in case of error
* git ignore temporary test fixtures

.gitignore

@@ -1,6 +1,7 @@
 /node_modules
 /test/js
 /test/browsertest/js
+/test/fixtures/temp-cache-fixture
 /benchmark/js
 /benchmark/fixtures
 /examples/*/js

lib/NoEmitOnErrorsPlugin.js

@@ -0,0 +1,19 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+function NoEmitOnErrorsPlugin() {}
+
+module.exports = NoEmitOnErrorsPlugin;
+NoEmitOnErrorsPlugin.prototype.apply = function(compiler) {
+	compiler.plugin("should-emit", function(compilation) {
+		if(compilation.errors.length > 0)
+			return false;
+	});
+	compiler.plugin("compilation", function(compilation) {
+		compilation.plugin("should-record", function() {
+			if(compilation.errors.length > 0)
+				return false;
+		});
+	});
+};

lib/NoErrorsPlugin.js

@@ -3,9 +3,17 @@
 	Author Tobias Koppers @sokra
 */
 function NoErrorsPlugin() {}
+
+var deprecationReported = false;
+
 module.exports = NoErrorsPlugin;
 NoErrorsPlugin.prototype.apply = function(compiler) {
 	compiler.plugin("should-emit", function(compilation) {
+		if(!deprecationReported) {
+			compilation.warnings.push("webpack: Using NoErrorsPlugin is deprecated.\n" +
+				"Use NoEmitOnErrorsPlugin instead.\n");
+			deprecationReported = true;
+		}
 		if(compilation.errors.length > 0)
 			return false;
 	});

lib/webpack.js

@@ -98,6 +98,7 @@ exportPlugins(exports, ".", [
 	"SetVarMainTemplatePlugin",
 	"UmdMainTemplatePlugin",
 	"NoErrorsPlugin",
+	"NoEmitOnErrorsPlugin",
 	"NewWatchingPlugin",
 	"EnvironmentPlugin",
 	"DllPlugin",

test/Errors.test.js

@@ -92,6 +92,58 @@ describe("Errors", function() {
 			done();
 		});
 	});
+	it("should warn about NoErrorsPlugin being deprecated in favor of NoEmitOnErrorsPlugin", function(done) {
+		getErrors({
+			entry: "./no-errors-deprecate",
+			plugins: [
+				new webpack.NoErrorsPlugin()
+			]
+		}, function(errors, warnings) {
+			warnings.length.should.be.eql(1);
+			var lines = warnings[0].split("\n");
+			lines[0].should.match(/webpack/);
+			lines[0].should.match(/NoErrorsPlugin/);
+			lines[0].should.match(/deprecated/);
+			lines[1].should.match(/NoEmitOnErrorsPlugin/);
+			lines[1].should.match(/instead/);
+			done();
+		});
+	});
+	it("should not warn if the NoEmitOnErrorsPlugin is used over the NoErrorsPlugin", function(done) {
+		getErrors({
+			entry: "./no-errors-deprecate",
+			plugins: [
+				new webpack.NoEmitOnErrorsPlugin()
+			]
+		}, function(errors, warnings) {
+			errors.length.should.be.eql(0);
+			warnings.length.should.be.eql(0);
+			done();
+		});
+	});
+	it("should not not emit if NoEmitOnErrorsPlugin is used and there is an error", function(done) {
+		getErrors({
+			entry: "./missingFile",
+			plugins: [
+				new webpack.NoEmitOnErrorsPlugin()
+			]
+		}, function(errors, warnings) {
+			errors.length.should.be.eql(2);
+			warnings.length.should.be.eql(0);
+			errors.sort();
+			var lines = errors[0].split("\n");
+			lines[0].should.match(/missingFile.js/);
+			lines[1].should.match(/^Module not found/);
+			lines[1].should.match(/\.\/dir\/missing2/);
+			lines[2].should.match(/missingFile.js 12:9/);
+			lines = errors[1].split("\n");
+			lines[0].should.match(/missingFile.js/);
+			lines[1].should.match(/^Module not found/);
+			lines[1].should.match(/\.\/missing/);
+			lines[2].should.match(/missingFile.js 4:0/);
+			done();
+		});
+	});
 	it("should throw an error when using incorrect CommonsChunkPlugin configuration", function(done) {
 		getErrors({
 			entry: {

test/fixtures/errors/no-errors-deprecate.js

@@ -0,0 +1 @@
+require('./file');