fix(build): properly handle alias key in config merge (vitejs#2847)

Co-authored-by: Anthony Fu <[email protected]>

packages/vite/src/node/__tests__/config.spec.ts

@@ -0,0 +1,94 @@
+import { mergeConfig, UserConfigExport } from '../config'
+
+describe('mergeConfig', () => {
+  test('handles configs with different alias schemas', () => {
+    const baseConfig: UserConfigExport = {
+      resolve: {
+        alias: [
+          {
+            find: 'foo',
+            replacement: 'foo-value'
+          }
+        ]
+      }
+    }
+
+    const newConfig: UserConfigExport = {
+      resolve: {
+        alias: {
+          bar: 'bar-value',
+          baz: 'baz-value'
+        }
+      }
+    }
+
+    const mergedConfig: UserConfigExport = {
+      resolve: {
+        alias: [
+          {
+            find: 'foo',
+            replacement: 'foo-value'
+          },
+          {
+            find: 'bar',
+            replacement: 'bar-value'
+          },
+          {
+            find: 'baz',
+            replacement: 'baz-value'
+          }
+        ]
+      }
+    }
+
+    expect(mergeConfig(baseConfig, newConfig)).toEqual(mergedConfig)
+  })
+
+  test('handles assetsInclude', () => {
+    const baseConfig: UserConfigExport = {
+      assetsInclude: 'some-string'
+    }
+
+    const newConfig: UserConfigExport = {
+      assetsInclude: ['some-other-string', /regexp?/]
+    }
+
+    const mergedConfig: UserConfigExport = {
+      assetsInclude: ['some-string', 'some-other-string', /regexp?/]
+    }
+
+    expect(mergeConfig(baseConfig, newConfig)).toEqual(mergedConfig)
+  })
+
+  test('not handles alias not under `resolve`', () => {
+    const baseConfig = {
+      custom: {
+        alias: {
+          bar: 'bar-value',
+          baz: 'baz-value'
+        }
+      }
+    }
+
+    const newConfig = {
+      custom: {
+        alias: {
+          bar: 'bar-value-2',
+          foo: 'foo-value'
+        }
+      }
+    }
+
+    const mergedConfig = {
+      custom: {
+        alias: {
+          bar: 'bar-value-2',
+          baz: 'baz-value',
+          foo: 'foo-value'
+        }
+      }
+    }
+
+    expect(mergeConfig(baseConfig, newConfig)).toEqual(mergedConfig)
+  })
+})

packages/vite/src/node/config.ts

@@ -502,11 +502,11 @@ function resolveBaseUrl(
   return base
 }
 
-export function mergeConfig(
+function mergeConfigRecursively(
   a: Record<string, any>,
   b: Record<string, any>,
-  isRoot = true
-): Record<string, any> {
+  rootPath: string
+) {
   const merged: Record<string, any> = { ...a }
   for (const key in b) {
     const value = b[key]
@@ -520,16 +520,20 @@ export function mergeConfig(
       continue
     }
     if (isObject(existing) && isObject(value)) {
-      merged[key] = mergeConfig(existing, value, false)
+      merged[key] = mergeConfigRecursively(
+        existing,
+        value,
+        rootPath ? `${rootPath}.${key}` : key
+      )
       continue
     }
 
-    // root fields that require special handling
-    if (existing != null && isRoot) {
-      if (key === 'alias') {
+    // fields that require special handling
+    if (existing != null) {
+      if (key === 'alias' && (rootPath === 'resolve' || rootPath === '')) {
         merged[key] = mergeAlias(existing, value)
         continue
-      } else if (key === 'assetsInclude') {
+      } else if (key === 'assetsInclude' && rootPath === '') {
         merged[key] = [].concat(existing, value)
         continue
       }
@@ -540,6 +544,14 @@ export function mergeConfig(
   return merged
 }
 
+export function mergeConfig(
+  a: Record<string, any>,
+  b: Record<string, any>,
+  isRoot = true
+): Record<string, any> {
+  return mergeConfigRecursively(a, b, isRoot ? '' : '.')
+}
+
 function mergeAlias(a: AliasOptions = [], b: AliasOptions = []): Alias[] {
   return [...normalizeAlias(a), ...normalizeAlias(b)]
 }