fix: rolldownOptions/rollupOptions merging at environment level (#21612)

jamesopstad · web-flow · commit db2ecc7675c3 · 2026-02-12T14:11:59.000+09:00
diff --git a/packages/vite/src/node/__tests__/config.spec.ts b/packages/vite/src/node/__tests__/config.spec.ts
@@ -617,6 +617,117 @@ describe('mergeConfig', () => {
       testRolldownOptions.environments.client.build.rolldownOptions.platform,
     ).toBe('browser')
   })
+
+  describe('later plugin can read `rollupOptions` set via `rolldownOptions` in earlier plugin', () => {
+    test('top-level config', async () => {
+      expect.assertions(2)
+      await resolveConfig(
+        {
+          plugins: [
+            {
+              name: 'plugin-a',
+              config() {
+                return {
+                  build: {
+                    rolldownOptions: {
+                      platform: 'neutral',
+                    },
+                  },
+                  worker: {
+                    rolldownOptions: {
+                      platform: 'neutral',
+                    },
+                  },
+                }
+              },
+            },
+            {
+              name: 'plugin-b',
+              config(config) {
+                expect(config.build?.rollupOptions?.platform).toBe('neutral')
+                expect(config.worker?.rollupOptions?.platform).toBe('neutral')
+              },
+            },
+          ],
+        },
+        'build',
+      )
+    })
+
+    test('new `environments` object', async () => {
+      expect.assertions(1)
+      await resolveConfig(
+        {
+          plugins: [
+            {
+              name: 'plugin-a',
+              config() {
+                return {
+                  environments: {
+                    ssr: {
+                      build: {
+                        rolldownOptions: {
+                          platform: 'neutral',
+                        },
+                      },
+                    },
+                  },
+                }
+              },
+            },
+            {
+              name: 'plugin-b',
+              config(config) {
+                expect(
+                  config.environments?.ssr?.build?.rollupOptions?.platform,
+                ).toBe('neutral')
+              },
+            },
+          ],
+        },
+        'build',
+      )
+    })
+
+    test('new environment on existing `environments` object', async () => {
+      expect.assertions(1)
+      await resolveConfig(
+        {
+          environments: {
+            // environments exists, but no ssr
+            client: {},
+          },
+          plugins: [
+            {
+              name: 'plugin-a',
+              config() {
+                return {
+                  environments: {
+                    ssr: {
+                      build: {
+                        rolldownOptions: {
+                          platform: 'neutral',
+                        },
+                      },
+                    },
+                  },
+                }
+              },
+            },
+            {
+              name: 'plugin-b',
+              config(config) {
+                expect(
+                  config.environments?.ssr?.build?.rollupOptions?.platform,
+                ).toBe('neutral')
+              },
+            },
+          ],
+        },
+        'build',
+      )
+    })
+  })
 })
 
 describe('resolveEnvPrefix', () => {
diff --git a/packages/vite/src/node/utils.ts b/packages/vite/src/node/utils.ts
@@ -1289,6 +1289,20 @@ const rollupOptionsRootPaths = new Set([
   'ssr.optimizeDeps',
 ])
 
+/**
+ * Sets up `rollupOptions` compat proxies for an environment.
+ */
+function setupRollupOptionCompatForEnvironment(environment: any): any {
+  if (!isObject(environment)) {
+    return environment
+  }
+  const merged: Record<string, any> = { ...environment }
+  if (isObject(merged.build)) {
+    setupRollupOptionCompat(merged.build, 'build')
+  }
+  return merged
+}
+
 export function hasBothRollupOptionsAndRolldownOptions(
   options: Record<string, any>,
 ): boolean {
@@ -1334,7 +1348,21 @@ function mergeConfigRecursively(
     }
 
     if (existing == null) {
-      merged[key] = value
+      if (rootPath === '' && key === 'environments' && isObject(value)) {
+        // Clone to avoid mutating the original override object
+        const environments = { ...value }
+        for (const envName in environments) {
+          environments[envName] = setupRollupOptionCompatForEnvironment(
+            environments[envName],
+          )
+        }
+        merged[key] = environments
+      } else if (rootPath === 'environments') {
+        // `environments` exists, but a new environment is added
+        merged[key] = setupRollupOptionCompatForEnvironment(value)
+      } else {
+        merged[key] = value
+      }
       continue
     }
 
