fix: restrict dev tsx loader to repo-local plugins (Windows external plugin workers)

server/src/__tests__/plugin-tsx-loader-condition.test.ts

@@ -0,0 +1,33 @@
+import { describe, expect, it } from "vitest";
+import path from "node:path";
+import { isRepoLocalPluginPath, REPO_ROOT } from "../services/plugin-loader.js";
+
+describe("isRepoLocalPluginPath", () => {
+  it("returns true for a package inside the repository", () => {
+    const pkgPath = path.join(REPO_ROOT, "packages", "plugins", "examples", "plugin-hello-world-example");
+    expect(isRepoLocalPluginPath(pkgPath)).toBe(true);
+  });
+
+  it("returns true when the package path equals the repository root", () => {
+    expect(isRepoLocalPluginPath(REPO_ROOT)).toBe(true);
+  });
+
+  it("returns false for a package outside the repository", () => {
+    const outside = path.join(REPO_ROOT, "..", "external-plugin");
+    expect(isRepoLocalPluginPath(outside)).toBe(false);
+  });
+
+  it("returns false for a sibling directory that merely shares the repo name prefix", () => {
+    const sibling = path.join(path.dirname(REPO_ROOT), path.basename(REPO_ROOT) + "-external");
+    expect(isRepoLocalPluginPath(sibling)).toBe(false);
+  });
+
+  it("returns false for null and undefined", () => {
+    expect(isRepoLocalPluginPath(null)).toBe(false);
+    expect(isRepoLocalPluginPath(undefined)).toBe(false);
+  });
+
+  it("returns false for an empty string", () => {
+    expect(isRepoLocalPluginPath("")).toBe(false);
+  });
+});

server/src/services/plugin-loader.ts

@@ -703,6 +703,19 @@ function isPathWithin(root: string, target: string): boolean {
   return relativePath === "" || (!relativePath.startsWith("..") && !path.isAbsolute(relativePath));
 }
 
+/**
+ * True when a plugin package path is inside this repository.
+ *
+ * The dev tsx loader is only applied to repo-local packages, because
+ * external plugins ship prebuilt JS and tsx's `--import` loader crashes
+ * on Windows when the worker entry is an absolute drive-letter path
+ * (ERR_UNSUPPORTED_ESM_URL_SCHEME, protocol 'e:').
+ */
+export function isRepoLocalPluginPath(packagePath: string | null | undefined): boolean {
+  if (!packagePath) return false;
+  return isPathWithin(REPO_ROOT, path.resolve(packagePath));
+}
+
 export function isRepoBundledPluginPath(
   packageRoot: string,
   options: { repoRoot?: string } = {},
@@ -2295,18 +2308,16 @@ export function pluginLoader(
       // entry as a raw drive-letter path (e.g. `E:\plugins\dist\worker.js`)
       // and fails with ERR_UNSUPPORTED_ESM_URL_SCHEME (protocol 'e:').
       // External plugins ship prebuilt JS and do not need the tsx loader.
-      const PLUGIN_REPO_ROOT = path.resolve(__dirname, "../../..");
       const resolvedPkgPath = activePlugin.packagePath
         ? path.resolve(activePlugin.packagePath)
         : null;
-      const isRepoLocalPlugin =
+      if (
         resolvedPkgPath !== null &&
-        (resolvedPkgPath === PLUGIN_REPO_ROOT ||
-          resolvedPkgPath.startsWith(PLUGIN_REPO_ROOT + path.sep));
-      if (isRepoLocalPlugin && existsSync(DEV_TSX_LOADER_PATH)) {
+        isRepoLocalPluginPath(resolvedPkgPath) &&
+        existsSync(DEV_TSX_LOADER_PATH)
+      ) {
         workerOptions.execArgv = ["--import", DEV_TSX_LOADER_PATH];
       }
-
       await workerManager.startWorker(pluginId, workerOptions);
       registered.worker = true;