feat: failOnWarnings option

OPTIONS.md

@@ -16,6 +16,7 @@ Options:
   --progress [value]                                                                 Print compilation progress during build.
   --prefetch <value>                                                                 Prefetch this request.
   -j, --json [value]                                                                 Prints result as JSON or store it in a file.
+  --no-fail-on-warnings                                                              Negative 'fail-on-warnings' option.
   --no-amd                                                                           Negative 'amd' option.
   --bail                                                                             Report the first error as a hard error instead of tolerating it.
   --no-bail                                                                          Negative 'bail' option.

packages/webpack-cli/src/types.ts

@@ -210,6 +210,7 @@ interface WebpackRunOptions extends WebpackOptionsNormalized {
   json?: boolean;
   argv?: Argv;
   env: Env;
+  failOnWarnings?: boolean;
 }
 
 /**

packages/webpack-cli/src/webpack-cli.ts

@@ -976,6 +976,17 @@ class WebpackCLI implements IWebpackCLI {
         description: "Stop watching when stdin stream has ended.",
         negatedDescription: "Do not stop watching when stdin stream has ended.",
       },
+      {
+        name: "fail-on-warnings",
+        configs: [
+          {
+            type: "enum",
+            values: [false],
+          },
+        ],
+        negative: true,
+        description: "Stop webpack-cli process with non-zero exit code on warnings from webpack",
+      },
     ];
 
     // Extract all the flags being exported from core.
@@ -2478,6 +2489,10 @@ class WebpackCLI implements IWebpackCLI {
           this.logger.raw(printedStats);
         }
       }
+
+      if (options.failOnWarnings && (stats.hasErrors() || stats.hasWarnings())) {
+        process.exit(1);
+      }
     };
 
     const env =

test/build/build-warnings/warnings.test.js

@@ -14,6 +14,15 @@ describe("warnings", () => {
     expect(stdout).toMatch(/Error: Can't resolve/);
   });
 
+  it("should exit with non-zero code on --fail-on-warnings flag", async () => {
+    const { exitCode, stderr, stdout } = await run(__dirname, ["--fail-on-warnings"]);
+
+    expect(exitCode).toBe(1);
+    expect(stderr).toBeFalsy();
+    expect(stdout).toMatch(/WARNING/);
+    expect(stdout).toMatch(/Error: Can't resolve/);
+  });
+
   it('should output JSON with the "json" flag', async () => {
     const { exitCode, stderr, stdout } = await run(__dirname, ["--json"]);