fix: skip empty channel doctor lookup

src/commands/doctor/shared/channel-doctor.test.ts

@@ -2,6 +2,7 @@ import { beforeEach, describe, expect, it, vi } from "vitest";
 import {
   collectChannelDoctorCompatibilityMutations,
   collectChannelDoctorEmptyAllowlistExtraWarnings,
+  collectChannelDoctorStaleConfigMutations,
   createChannelDoctorEmptyAllowlistPolicyHooks,
 } from "./channel-doctor.js";
 
@@ -49,6 +50,22 @@ describe("channel doctor compatibility mutations", () => {
     expect(mocks.resolveReadOnlyChannelPluginsForConfig).not.toHaveBeenCalled();
   });
 
+  it("skips plugin discovery when only channel defaults are configured", async () => {
+    const result = await collectChannelDoctorStaleConfigMutations({
+      channels: {
+        defaults: {
+          enabled: true,
+        },
+      },
+    } as never);
+
+    expect(result).toEqual([]);
+    expect(mocks.resolveReadOnlyChannelPluginsForConfig).not.toHaveBeenCalled();
+    expect(mocks.getLoadedChannelPlugin).not.toHaveBeenCalled();
+    expect(mocks.getBundledChannelSetupPlugin).not.toHaveBeenCalled();
+    expect(mocks.getBundledChannelPlugin).not.toHaveBeenCalled();
+  });
+
   it("uses read-only doctor adapters for configured channel ids", () => {
     const normalizeCompatibilityConfig = vi.fn(({ cfg }: { cfg: unknown }) => ({
       config: cfg,

src/commands/doctor/shared/channel-doctor.ts

@@ -80,6 +80,9 @@ function listChannelDoctorEntries(
   channelIds: readonly string[],
   context: ChannelDoctorLookupContext,
 ): ChannelDoctorEntry[] {
+  if (channelIds.length === 0) {
+    return [];
+  }
   const byId = new Map<string, ChannelDoctorEntry>();
   const selectedIds = new Set(channelIds);
   const readOnlyPlugins = safeListReadOnlyChannelPlugins(context).filter((plugin) =>