feat(migration): support monorepo peerDependencies detection

Find the nearest package.json for each source file instead of only
checking the root. This allows monorepos to have different packages
with different peerDependencies - a vite plugin package can have vite
in peerDependencies (imports preserved) while an app package without
peerDependencies will have imports rewritten.

- Add find_nearest_package_json() to walk up directories
- Cache package.json lookups for performance
- Add monorepo unit tests and snap-test

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: fengmk2

.github/workflows/e2e-test.yml

@@ -9,6 +9,10 @@ on:
       - main
     paths-ignore:
       - '**/*.md'
+  pull_request:
+    paths:
+      - 'ecosystem-ci/**'
+      - '.github/workflows/e2e-test.yml'
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.sha }}
@@ -88,6 +92,14 @@ jobs:
               vite run lint
               vite run type
               vite run test -- --coverage
+          - name: vite-plugin-react
+            node-version: 22
+            command: |
+              vite run format
+              vite run lint -- --fix
+              # TODO(fengmk2): run all builds and tests after tsdown version upgrade
+              vite run @vitejs/plugin-rsc#build
+              vite run @vitejs/plugin-rsc#test
 
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2

crates/vite_migration/src/import_rewriter.rs

@@ -1,4 +1,7 @@
-use std::path::{Path, PathBuf};
+use std::{
+    collections::HashMap,
+    path::{Path, PathBuf},
+};
 
 use vite_error::Error;
 
@@ -289,12 +292,33 @@ impl SkipPackages {
     }
 }
 
-/// Parse package.json at the root and check which packages are in peerDependencies.
-/// Returns default (no skipping) if package.json doesn't exist or can't be parsed.
-fn get_skip_packages_from_root(root: &Path) -> SkipPackages {
-    let package_json_path = root.join("package.json");
+/// Find the nearest package.json by walking up from the file's directory.
+/// Stops at the root directory.
+fn find_nearest_package_json(file_path: &Path, root: &Path) -> Option<PathBuf> {
+    let mut current = file_path.parent()?;
+
+    loop {
+        let package_json = current.join("package.json");
+        if package_json.exists() {
+            return Some(package_json);
+        }
+
+        // Stop if we've reached the root
+        if current == root {
+            break;
+        }
 
-    let content = match std::fs::read_to_string(&package_json_path) {
+        // Move to parent directory
+        current = current.parent()?;
+    }
+
+    None
+}
+
+/// Parse package.json and check which packages are in peerDependencies.
+/// Returns default (no skipping) if package.json doesn't exist or can't be parsed.
+fn get_skip_packages_from_package_json(package_json_path: &Path) -> SkipPackages {
+    let content = match std::fs::read_to_string(package_json_path) {
         Ok(c) => c,
         Err(_) => return SkipPackages::default(),
     };
@@ -374,16 +398,27 @@ pub fn rewrite_imports_in_directory(root: &Path) -> Result<BatchRewriteResult, E
         errors: Vec::new(),
     };
 
-    // Check package.json at root for peerDependencies
-    let skip_packages = get_skip_packages_from_root(root);
-
-    // If all packages are in peerDeps, skip all files
-    if skip_packages.all_skipped() {
-        result.unchanged_files = walk_result.files;
-        return Ok(result);
-    }
+    // Cache package.json lookups to avoid re-reading the same file
+    let mut skip_packages_cache: HashMap<PathBuf, SkipPackages> = HashMap::new();
 
     for file_path in walk_result.files {
+        // Find the nearest package.json for this file
+        let skip_packages =
+            if let Some(package_json_path) = find_nearest_package_json(&file_path, root) {
+                skip_packages_cache
+                    .entry(package_json_path.clone())
+                    .or_insert_with(|| get_skip_packages_from_package_json(&package_json_path))
+                    .clone()
+            } else {
+                SkipPackages::default()
+            };
+
+        // If all packages are in peerDeps for this file's package, skip it
+        if skip_packages.all_skipped() {
+            result.unchanged_files.push(file_path);
+            continue;
+        }
+
         match rewrite_import(&file_path, &skip_packages) {
             Ok(rewrite_result) => {
                 if rewrite_result.updated {
@@ -1675,7 +1710,7 @@ export default defineConfig({});"#;
     }
 
     #[test]
-    fn test_get_skip_packages_from_root_with_vite_peer_dep() {
+    fn test_get_skip_packages_from_package_json_with_vite_peer_dep() {
         use std::fs;
 
         let temp = tempdir().unwrap();
@@ -1687,16 +1722,17 @@ export default defineConfig({});"#;
     "vite": "^5.0.0"
   }
 }"#;
-        fs::write(temp.path().join("package.json"), pkg_json).unwrap();
+        let package_json_path = temp.path().join("package.json");
+        fs::write(&package_json_path, pkg_json).unwrap();
 
-        let skip = get_skip_packages_from_root(temp.path());
+        let skip = get_skip_packages_from_package_json(&package_json_path);
         assert!(skip.skip_vite);
         assert!(!skip.skip_vitest);
         assert!(!skip.skip_tsdown);
     }
 
     #[test]
-    fn test_get_skip_packages_from_root_with_all_peer_deps() {
+    fn test_get_skip_packages_from_package_json_with_all_peer_deps() {
         use std::fs;
 
         let temp = tempdir().unwrap();
@@ -1709,17 +1745,18 @@ export default defineConfig({});"#;
     "tsdown": "^1.0.0"
   }
 }"#;
-        fs::write(temp.path().join("package.json"), pkg_json).unwrap();
+        let package_json_path = temp.path().join("package.json");
+        fs::write(&package_json_path, pkg_json).unwrap();
 
-        let skip = get_skip_packages_from_root(temp.path());
+        let skip = get_skip_packages_from_package_json(&package_json_path);
         assert!(skip.skip_vite);
         assert!(skip.skip_vitest);
         assert!(skip.skip_tsdown);
         assert!(skip.all_skipped());
     }
 
     #[test]
-    fn test_get_skip_packages_from_root_no_peer_deps() {
+    fn test_get_skip_packages_from_package_json_no_peer_deps() {
         use std::fs;
 
         let temp = tempdir().unwrap();
@@ -1730,20 +1767,22 @@ export default defineConfig({});"#;
     "vite": "^5.0.0"
   }
 }"#;
-        fs::write(temp.path().join("package.json"), pkg_json).unwrap();
+        let package_json_path = temp.path().join("package.json");
+        fs::write(&package_json_path, pkg_json).unwrap();
 
-        let skip = get_skip_packages_from_root(temp.path());
+        let skip = get_skip_packages_from_package_json(&package_json_path);
         assert!(!skip.skip_vite);
         assert!(!skip.skip_vitest);
         assert!(!skip.skip_tsdown);
     }
 
     #[test]
-    fn test_get_skip_packages_from_root_no_package_json() {
+    fn test_get_skip_packages_from_package_json_no_file() {
         let temp = tempdir().unwrap();
 
         // No package.json created - should return default (no skipping)
-        let skip = get_skip_packages_from_root(temp.path());
+        let package_json_path = temp.path().join("package.json");
+        let skip = get_skip_packages_from_package_json(&package_json_path);
         assert!(!skip.skip_vite);
         assert!(!skip.skip_vitest);
         assert!(!skip.skip_tsdown);
@@ -1826,4 +1865,111 @@ import { build } from 'tsdown';"#;
         let content = fs::read_to_string(temp.path().join("index.ts")).unwrap();
         assert_eq!(content, original_content);
     }
+
+    #[test]
+    fn test_find_nearest_package_json() {
+        use std::fs;
+
+        let temp = tempdir().unwrap();
+
+        // Create monorepo structure
+        fs::create_dir_all(temp.path().join("packages/vite-plugin/src")).unwrap();
+        fs::create_dir_all(temp.path().join("packages/app/src")).unwrap();
+
+        // Root package.json (no peerDeps)
+        fs::write(temp.path().join("package.json"), r#"{"name": "monorepo"}"#).unwrap();
+
+        // vite-plugin package.json (has vite in peerDeps)
+        fs::write(
+            temp.path().join("packages/vite-plugin/package.json"),
+            r#"{"name": "vite-plugin", "peerDependencies": {"vite": "^5.0.0"}}"#,
+        )
+        .unwrap();
+
+        // app package.json (no peerDeps)
+        fs::write(temp.path().join("packages/app/package.json"), r#"{"name": "app"}"#).unwrap();
+
+        // Test finding package.json from vite-plugin/src/index.ts
+        let file_path = temp.path().join("packages/vite-plugin/src/index.ts");
+        let result = find_nearest_package_json(&file_path, temp.path());
+        assert_eq!(result, Some(temp.path().join("packages/vite-plugin/package.json")));
+
+        // Test finding package.json from app/src/index.ts
+        let file_path = temp.path().join("packages/app/src/index.ts");
+        let result = find_nearest_package_json(&file_path, temp.path());
+        assert_eq!(result, Some(temp.path().join("packages/app/package.json")));
+
+        // Test finding package.json from root level file
+        let file_path = temp.path().join("vite.config.ts");
+        let result = find_nearest_package_json(&file_path, temp.path());
+        assert_eq!(result, Some(temp.path().join("package.json")));
+    }
+
+    #[test]
+    fn test_rewrite_imports_monorepo_different_peer_deps() {
+        use std::fs;
+
+        let temp = tempdir().unwrap();
+
+        // Create monorepo structure
+        fs::create_dir_all(temp.path().join("packages/vite-plugin/src")).unwrap();
+        fs::create_dir_all(temp.path().join("packages/app/src")).unwrap();
+
+        // Root package.json (no peerDeps)
+        fs::write(temp.path().join("package.json"), r#"{"name": "monorepo"}"#).unwrap();
+
+        // vite-plugin package.json (has vite in peerDeps)
+        fs::write(
+            temp.path().join("packages/vite-plugin/package.json"),
+            r#"{"name": "vite-plugin", "peerDependencies": {"vite": "^5.0.0"}}"#,
+        )
+        .unwrap();
+
+        // app package.json (no peerDeps)
+        fs::write(temp.path().join("packages/app/package.json"), r#"{"name": "app"}"#).unwrap();
+
+        // vite-plugin source file with vite and vitest imports
+        fs::write(
+            temp.path().join("packages/vite-plugin/src/index.ts"),
+            r#"import { defineConfig } from 'vite';
+import { describe } from 'vitest';
+export default defineConfig({});"#,
+        )
+        .unwrap();
+
+        // app source file with vite and vitest imports
+        fs::write(
+            temp.path().join("packages/app/src/index.ts"),
+            r#"import { defineConfig } from 'vite';
+import { describe } from 'vitest';
+export default defineConfig({});"#,
+        )
+        .unwrap();
+
+        // Run the batch rewrite
+        let result = rewrite_imports_in_directory(temp.path()).unwrap();
+
+        // Both files should be modified
+        assert_eq!(result.modified_files.len(), 2);
+
+        // vite-plugin: vite NOT rewritten (has peerDep), vitest IS rewritten
+        let vite_plugin_content =
+            fs::read_to_string(temp.path().join("packages/vite-plugin/src/index.ts")).unwrap();
+        assert_eq!(
+            vite_plugin_content,
+            r#"import { defineConfig } from 'vite';
+import { describe } from '@voidzero-dev/vite-plus/test';
+export default defineConfig({});"#
+        );
+
+        // app: vite IS rewritten (no peerDep), vitest IS rewritten
+        let app_content =
+            fs::read_to_string(temp.path().join("packages/app/src/index.ts")).unwrap();
+        assert_eq!(
+            app_content,
+            r#"import { defineConfig } from '@voidzero-dev/vite-plus';
+import { describe } from '@voidzero-dev/vite-plus/test';
+export default defineConfig({});"#
+        );
+    }
 }

ecosystem-ci/.gitignore

@@ -3,3 +3,4 @@ skeleton
 rollipop
 frm-stack
 vue-mini
+vite-plugin-react

ecosystem-ci/repo.json

@@ -23,5 +23,10 @@
     "repository": "https://github.com/vue-mini/vue-mini.git",
     "branch": "master",
     "hash": "c51332662993dde44f665822bdea94cd0abf368b"
+  },
+  "vite-plugin-react": {
+    "repository": "https://github.com/vitejs/vite-plugin-react.git",
+    "branch": "main",
+    "hash": "0d3912b73d3aa1dc8f64619c82b3dacb0769e49e"
   }
 }

packages/global/snap-tests/migration-monorepo-skip-vite-peer-dependency/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "migration-monorepo-skip-vite-peer-dependency"
+}

packages/global/snap-tests/migration-monorepo-skip-vite-peer-dependency/packages/app/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "my-app",
+  "dependencies": {
+    "my-vite-plugin": "workspace:*"
+  }
+}

packages/global/snap-tests/migration-monorepo-skip-vite-peer-dependency/packages/app/src/index.ts

@@ -0,0 +1,13 @@
+import { myVitePlugin } from 'my-vite-plugin';
+import { defineConfig } from 'vite';
+import { describe, it, expect } from 'vitest';
+
+export default defineConfig({
+  plugins: [myVitePlugin()],
+});
+
+describe('app', () => {
+  it('should work', () => {
+    expect(true).toBe(true);
+  });
+});

packages/global/snap-tests/migration-monorepo-skip-vite-peer-dependency/packages/vite-plugin/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "my-vite-plugin",
+  "peerDependencies": {
+    "vite": "^6.0.0"
+  }
+}

packages/global/snap-tests/migration-monorepo-skip-vite-peer-dependency/packages/vite-plugin/src/index.ts

@@ -0,0 +1,21 @@
+import { defineConfig, type Plugin } from 'vite';
+import { describe, it, expect } from 'vitest';
+
+export function myVitePlugin(): Plugin {
+  return {
+    name: 'my-vite-plugin',
+    configResolved(config) {
+      console.log(config);
+    },
+  };
+}
+
+describe('myVitePlugin', () => {
+  it('should work', () => {
+    expect(myVitePlugin()).toBeDefined();
+  });
+});
+
+export default defineConfig({
+  plugins: [myVitePlugin()],
+});

packages/global/snap-tests/migration-monorepo-skip-vite-peer-dependency/pnpm-workspace.yaml

@@ -0,0 +1,2 @@
+packages:
+  - packages/*