diff --git a/src/plugins/install.test.ts b/src/plugins/install.test.ts
index 4513539dd400..2561aff9fdc2 100644
--- a/src/plugins/install.test.ts
+++ b/src/plugins/install.test.ts
@@ -2623,8 +2623,8 @@ describe("installPluginFromNpmSpec", () => {
 
     expect(result!.ok).toBe(false);
     if (!result!.ok) {
-      expect(result!.code, result!.error).toBe(PLUGIN_INSTALL_ERROR_CODE.SECURITY_SCAN_BLOCKED);
-      expect(result!.error).toContain("npm installs are disabled by policy");
+      expect(result.code, result.error).toBe(PLUGIN_INSTALL_ERROR_CODE.SECURITY_SCAN_BLOCKED);
+      expect(result.error).toContain("npm installs are disabled by policy");
     }
     expect(vi.mocked(runCommandWithTimeout)).toHaveBeenCalledTimes(1);
     expect(vi.mocked(runCommandWithTimeout).mock.calls[0]?.[0]).toEqual([
diff --git a/src/plugins/install.ts b/src/plugins/install.ts
index 53dabe2aceb4..225290310c0c 100644
--- a/src/plugins/install.ts
+++ b/src/plugins/install.ts
@@ -1839,6 +1839,7 @@ function sourceFamilyForInstallPolicyKind(
     case undefined:
       return fallback;
   }
+  return fallback;
 }
 
 type PreparedInstallTarget = {
@@ -3074,11 +3075,11 @@ export async function installPluginFromNpmPackArchive(
   }
   const packageName = packageNameResult.packageName;
   const npmBaseDir = params.npmDir ? resolveUserPath(params.npmDir) : resolveDefaultPluginNpmDir();
-  const npmRoot = resolvePluginNpmProjectDir({
+  const npmProjectRoot = resolvePluginNpmProjectDir({
     npmDir: npmBaseDir,
     packageName,
   });
-  const installRoot = resolveManagedNpmRootPackageDir(npmRoot, packageName);
+  const installRoot = resolveManagedNpmRootPackageDir(npmProjectRoot, packageName);
   const effectiveMode = await resolveEffectiveInstallMode({
     runtime,
     requestedMode: mode,