fix(plugins): detect install root rebinding

src/infra/install-package-dir.test.ts

@@ -218,7 +218,7 @@ describe("installPackageDir", () => {
       installBaseDir,
       preservedDir: preservedInstallRoot,
       outsideTarget: outsideInstallRoot,
-      rebindAtCall: 3,
+      rebindAtCall: 4,
       run: async () => {
         await expect(
           installPackageDir({
@@ -259,7 +259,7 @@ describe("installPackageDir", () => {
       installBaseDir,
       preservedDir: preservedInstallRoot,
       outsideTarget: outsideInstallRoot,
-      rebindAtCall: 7,
+      rebindAtCall: 8,
       run: async () =>
         await installPackageDir({
           sourceDir,

src/infra/install-package-dir.ts

@@ -170,11 +170,17 @@ export async function installPackageDir(params: {
 }): Promise<{ ok: true } | { ok: false; error: string; code?: string }> {
   params.logger?.info?.(`Installing to ${params.targetDir}…`);
   const installBaseDir = path.dirname(params.targetDir);
-  await fs.mkdir(installBaseDir, { recursive: true });
-  await assertInstallBoundaryPaths({
-    installBaseDir,
-    candidatePaths: [params.targetDir],
-  });
+  let initialInstallBaseRealPath: string;
+  try {
+    await fs.mkdir(installBaseDir, { recursive: true });
+    initialInstallBaseRealPath = await fs.realpath(installBaseDir);
+    await assertInstallBoundaryPaths({
+      installBaseDir,
+      candidatePaths: [params.targetDir],
+    });
+  } catch (err) {
+    return { ok: false, error: `${params.copyErrorPrefix}: ${String(err)}` };
+  }
   let installBaseRealPath: string;
   let canonicalTargetDir: string;
   try {
@@ -182,7 +188,13 @@ export async function installPackageDir(params: {
       installBaseDir,
       targetDir: params.targetDir,
     }));
+    if (installBaseRealPath !== initialInstallBaseRealPath) {
+      throw new Error(INSTALL_BASE_CHANGED_ERROR_MESSAGE);
+    }
   } catch (err) {
+    if (isInstallBaseChangedError(err)) {
+      params.logger?.warn?.(INSTALL_BASE_CHANGED_ABORT_WARNING);
+    }
     return { ok: false, error: `${params.copyErrorPrefix}: ${String(err)}` };
   }