fix(core): treat hubs without plugin command RPCs as having no commands (#15188)

* fix(core): own plugin commands in the runtime and hub

* fix(core): treat hubs without plugin command RPCs as having no commands

A running Hub that predates plugins.commands.* replies unsupported_command, and
replacement defers while it has active work. The client threw on that reply, so
every non-built-in slash command, skills included, failed in Desktop until the
old Hub exited. Return an empty catalog and no command result instead.

Co-authored-by: Saoud Rizwan <saoudrizwan@users.noreply.github.com>

* fix(core): catch the unsupported_command error the hub client throws

NodeHubClient.command() throws HubCommandError for a non-ok reply, so checking
the reply never saw an older Hub's unsupported_command. Catch the thrown error
instead, and make the regression test reject the way the real client does.

Co-authored-by: Saoud Rizwan <saoudrizwan@users.noreply.github.com>

---------

Co-authored-by: abeatrix <beatrix@cline.bot>
Co-authored-by: Saoud Rizwan <saoudrizwan@users.noreply.github.com>

sdk/packages/core/src/hub/client/plugin-commands.ts

@@ -1,9 +1,33 @@
+import type { HubCommandEnvelope, HubReplyEnvelope } from "@cline/shared";
 import type {
 	PluginCommandCatalog,
 	PluginCommandResult,
 	PluginCommandsApi,
 } from "../../services/plugin-command-api";
-import type { NodeHubClient } from "./index";
+import { HubCommandError, type NodeHubClient } from "./index";
+
+/**
+ * A Hub that predates plugin command RPCs, kept alive while it has active
+ * work, answers unsupported_command. Resolves undefined for that Hub.
+ */
+async function commandIfSupported(
+	client: Pick<NodeHubClient, "command">,
+	command: HubCommandEnvelope["command"],
+	payload: Record<string, unknown>,
+	sessionId: string | undefined,
+	options: Parameters<NodeHubClient["command"]>[3],
+): Promise<HubReplyEnvelope | undefined> {
+	try {
+		return await client.command(command, payload, sessionId, options);
+	} catch (error) {
+		if (
+			error instanceof HubCommandError &&
+			error.code === "unsupported_command"
+		)
+			return undefined;
+		throw error;
+	}
+}
 
 /** Uses the caller's existing connection and subscription lifecycle. */
 export function createHubPluginCommandsApi(
@@ -11,12 +35,14 @@ export function createHubPluginCommandsApi(
 ): PluginCommandsApi {
 	return {
 		async list(target) {
-			const reply = await client.command(
+			const reply = await commandIfSupported(
+				client,
 				"plugins.commands.list",
 				{ ...target },
 				target.sessionId,
 				{ timeoutMs: null },
 			);
+			if (!reply) return { ...target, status: "ready", commands: [] };
 			if (!reply.ok)
 				throw new Error(
 					reply.error?.message ?? "Plugin command discovery failed",
@@ -24,12 +50,14 @@ export function createHubPluginCommandsApi(
 			return reply.payload?.catalog as unknown as PluginCommandCatalog;
 		},
 		async run(input) {
-			const reply = await client.command(
+			const reply = await commandIfSupported(
+				client,
 				"plugins.commands.run",
 				{ ...input },
 				input.sessionId,
 				{ timeoutMs: null, retryAfterDispatch: false },
 			);
+			if (!reply) return undefined;
 			if (!reply.ok)
 				throw new Error(
 					reply.error?.message ?? "Plugin command execution failed",

sdk/packages/core/src/hub/server/plugin-commands.test.ts

@@ -7,6 +7,7 @@ import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { LocalRuntimeHost } from "../../runtime/host/local-runtime-host";
 import { splitCoreSessionConfig } from "../../runtime/host/runtime-host";
 import { FileSessionService } from "../../session/services/file-session-service";
+import { HubCommandError } from "../client";
 import { createHubPluginCommandsApi } from "../client/plugin-commands";
 import { createLocalHubScheduleRuntimeHandlers } from "../daemon/runtime-handlers";
 import { HubServerTransport } from "./hub-server-transport";
@@ -265,6 +266,26 @@ api.registerCommand({name:'recovered',handler:()=> 'ready'});
 		});
 		stop();
 	});
+	it("treats a Hub without plugin command RPCs as having no plugin commands", async () => {
+		const api = createHubPluginCommandsApi({
+			command: async (name) => {
+				throw new HubCommandError(
+					name,
+					"unsupported_command",
+					`Unsupported hub schedule command: ${name}`,
+				);
+			},
+			subscribe: () => () => {},
+		});
+		expect(await api.list({ workspacePath: root })).toEqual({
+			workspacePath: root,
+			status: "ready",
+			commands: [],
+		});
+		expect(
+			await api.run({ workspacePath: root, prompt: "/counter" }),
+		).toBeUndefined();
+	});
 	it("shares a workspace sandbox across client requests and preserves arguments", async () => {
 		const first = await command("plugins.commands.list", {
 			workspacePath: root,