From d6380bb6c6756d2a00ac20f2ffc454481d97e4d3 Mon Sep 17 00:00:00 2001
From: Alexander Akait <4567934+alexander-akait@users.noreply.github.com>
Date: Thu, 31 Dec 2020 19:47:43 +0300
Subject: [PATCH] fix: provide useful error on unknown command

---
 packages/webpack-cli/lib/webpack-cli.js | 18 +++++++++++++++++-
 test/unknown/unknown.test.js            | 18 ++++++++++++++----
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/packages/webpack-cli/lib/webpack-cli.js b/packages/webpack-cli/lib/webpack-cli.js
index c3b91fc554e..2f85a0c85ee 100644
--- a/packages/webpack-cli/lib/webpack-cli.js
+++ b/packages/webpack-cli/lib/webpack-cli.js
@@ -273,6 +273,9 @@ class WebpackCLI {
             },
         ];
 
+        const knownCommands = [bundleCommandOptions, versionCommandOptions, helpCommandOptions, ...externalBuiltInCommandsInfo];
+        const isKnownCommand = (name) => knownCommands.find((command) => command.name === name || command.alias === name);
+
         const getCommandNameAndOptions = (args) => {
             let commandName;
             const options = [];
@@ -687,7 +690,20 @@ class WebpackCLI {
                 await outputVersion(optionsForVersion, program);
             }
 
-            await loadCommandByName(commandName, true);
+            if (isKnownCommand(commandName)) {
+                await loadCommandByName(commandName, true);
+            } else {
+                logger.error(`Unknown command '${commandName}'`);
+
+                const found = knownCommands.find((commandOptions) => distance(commandName, commandOptions.name) < 3);
+
+                if (found) {
+                    logger.error(`Did you mean '${found.name}' (alias '${found.alias}')?`);
+                }
+
+                logger.error("Run 'webpack --help' to see available commands and options");
+                process.exit(2);
+            }
 
             await this.program.parseAsync([commandName, ...options], { from: 'user' });
         });
diff --git a/test/unknown/unknown.test.js b/test/unknown/unknown.test.js
index bb8ba841b06..78258b22580 100644
--- a/test/unknown/unknown.test.js
+++ b/test/unknown/unknown.test.js
@@ -184,12 +184,22 @@ describe('unknown behaviour', () => {
         expect(stdout).toBeFalsy();
     });
 
-    it('should ask to install command if an unknown command passed', () => {
+    it('should log error if an unknown command passed', () => {
         const { exitCode, stderr, stdout } = run(__dirname, ['qqq'], true, [], { TERM_PROGRAM: false });
 
-        expect(exitCode).toBe(0);
-        expect(stripAnsi(stderr)).toContain("For using this command you need to install: 'qqq' package");
-        expect(stripAnsi(stderr)).toContain("Would you like to install 'qqq' package? (That will run 'npm install -D qqq')");
+        expect(exitCode).toBe(2);
+        expect(stripAnsi(stderr)).toContain("Unknown command 'qqq'");
+        expect(stripAnsi(stderr)).toContain("Run 'webpack --help' to see available commands and options");
+        expect(stdout).toBeFalsy();
+    });
+
+    it('should log error and provide suggestion if an unknown command passed', () => {
+        const { exitCode, stderr, stdout } = run(__dirname, ['server'], true, [], { TERM_PROGRAM: false });
+
+        expect(exitCode).toBe(2);
+        expect(stripAnsi(stderr)).toContain("Unknown command 'server'");
+        expect(stripAnsi(stderr)).toContain("Did you mean 'serve' (alias 's')?");
+        expect(stripAnsi(stderr)).toContain("Run 'webpack --help' to see available commands and options");
         expect(stdout).toBeFalsy();
     });
 });