Defer resolve entry points in webpack plugin (resolves #949)

packages/knip/fixtures/plugins/webpack/webpack.dev.js

@@ -6,8 +6,8 @@ module.exports = env =>
   merge(common(), {
     mode: env.production ? 'production' : 'development',
     entry: {
-      main: './src/app.ts',
-      vendor: './src/vendor.ts',
+      main: './src/app',
+      vendor: './src/vendor',
     },
     module: {
       rules: [

packages/knip/fixtures/plugins/webpack2/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "@fixtures/webpack2",
+  "scripts": {
+    "dev": "webpack --config webpack.dev.js",
+    "prod": "webpack --config webpack.prod.js"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "webpack": "*",
+    "webpack-cli": "*"
+  }
+}

packages/knip/fixtures/plugins/webpack2/webpack.dev.js

@@ -0,0 +1,8 @@
+import 'webpack';
+
+export default () => {
+  return {
+    mode: 'development',
+    entry: './entry.dev.js',
+  };
+};

packages/knip/fixtures/plugins/webpack2/webpack.prod.js

@@ -0,0 +1,8 @@
+import 'webpack';
+
+export default () => {
+  return {
+    mode: 'production',
+    entry: './entry.prod.js',
+  };
+};

packages/knip/src/plugins/webpack/index.ts

@@ -4,10 +4,10 @@ import { compact } from '../../util/array.js';
 import {
   type Input,
   toDeferResolve,
+  toDeferResolveEntry,
+  toDeferResolveProductionEntry,
   toDependency,
   toDevDependency,
-  toEntry,
-  toProductionEntry,
 } from '../../util/input.js';
 import { isAbsolute, isInternal, join, relative } from '../../util/path.js';
 import { hasDependency } from '../../util/plugin.js';
@@ -99,8 +99,9 @@ export const findWebpackDependenciesFromConfig = async ({ config, cwd }: { confi
         } else {
           const absoluteEntry = isAbsolute(entry) ? entry : join(options.context ? options.context : cwd, entry);
           const item = relative(cwd, absoluteEntry);
-          const value = options.mode === 'development' ? toEntry(item) : toProductionEntry(item);
-          inputs.add(value);
+          const input =
+            options.mode === 'development' ? toDeferResolveEntry(item) : toDeferResolveProductionEntry(item);
+          inputs.add(input);
         }
       }
     }

packages/knip/test/plugins/webpack2.test.ts

@@ -0,0 +1,35 @@
+import { test } from 'bun:test';
+import assert from 'node:assert/strict';
+import { main } from '../../src/index.js';
+import { resolve } from '../../src/util/path.js';
+import baseArguments from '../helpers/baseArguments.js';
+import baseCounters from '../helpers/baseCounters.js';
+
+const cwd = resolve('fixtures/plugins/webpack2');
+
+test('Find dependencies with Webpack plugin (2)', async () => {
+  const { counters } = await main({
+    ...baseArguments,
+    cwd,
+  });
+
+  assert.deepEqual(counters, {
+    ...baseCounters,
+    processed: 4,
+    total: 4,
+  });
+});
+
+test('Find dependencies with Webpack plugin (2) (production)', async () => {
+  const { counters } = await main({
+    ...baseArguments,
+    cwd,
+    isProduction: true,
+  });
+
+  assert.deepEqual(counters, {
+    ...baseCounters,
+    processed: 1,
+    total: 1,
+  });
+});