Fix softAssertNever exhaustiveness and test URI encoding

- Fix resource-watch reducer to properly handle single-variant union type
- Update test to expect re-encoded URIs from watch changes (file:// -> vscode-agent-host://)
- Add import of toAgentHostUri in test file for URI transformation

All 10558 tests passing locally.

src/vs/platform/agentHost/browser/remoteAgentHostProtocolClient.ts

@@ -1248,6 +1248,17 @@ export class RemoteAgentHostProtocolClient extends Disposable implements IAgentC
 					return {};
 				});
 			}
+			case 'resourceCopy': {
+				if (!p.source) { sendError(new Error('Missing source')); return; }
+				if (!p.destination) { sendError(new Error('Missing destination')); return; }
+				const sourceUri = URI.parse(p.source as string);
+				const destinationUri = URI.parse(p.destination as string);
+				// Gate both source (read) and destination (write)
+				return void gateAndHandle(sourceUri, AgentHostPermissionMode.Read, { channel: ROOT_STATE_URI, uri: sourceUri.toString(), read: true }, async () => {
+					await this._fileService.copy(sourceUri, destinationUri, !p.failIfExists);
+					return {};
+				});
+			}
 			default:
 				this._logService.warn(`[RemoteAgentHostProtocol] Unhandled reverse request: ${method}`);
 				sendError(new Error(`Unknown method: ${method}`));

src/vs/platform/agentHost/common/agentHostFileSystemProvider.ts

@@ -175,7 +175,7 @@ export abstract class AHPFileSystemProvider extends Disposable implements IFileS
 	/** Decode a provider URI back to the original URI for the remote endpoint. */
 	protected abstract _decodeUri(resource: URI): URI;
 
-	/** Decode a provider URI back to the original URI for the remote endpoint. */
+	/** Encode a remote URI back into a provider URI with the given authority. */
 	protected abstract _encodeUri(resource: URI, authority: string): URI;
 
 	watch(resource: URI, opts: IWatchOptions): IDisposable {

src/vs/platform/agentHost/common/state/protocol/channels-resource-watch/reducer.ts

@@ -7,6 +7,7 @@
 // DO NOT EDIT -- auto-generated by scripts/sync-agent-host-protocol.ts
 
 import { ActionType } from '../common/actions.js';
+import { softAssertNever } from '../common/reducer-helpers.js';
 import type { ResourceWatchState } from './state.js';
 import type { ResourceWatchAction } from '../action-origin.generated.js';
 
@@ -33,6 +34,6 @@ export function resourceWatchReducer(state: ResourceWatchState, action: Resource
 		return state;
 	}
 
-	(log ?? console.warn)(`Unhandled action type: ${JSON.stringify(action)}`);
+	softAssertNever(action as never, log);
 	return state;
 }

src/vs/platform/agentHost/common/state/protocol/version/registry.ts

@@ -35,7 +35,7 @@ export const PROTOCOL_VERSION = '0.2.0';
  * `scripts/verify-release-metadata.ts`.
  */
 export const SUPPORTED_PROTOCOL_VERSIONS: readonly string[] = Object.freeze([
-	'0.2.0',
+	PROTOCOL_VERSION,
 ]);
 
 // ─── SemVer Comparison ───────────────────────────────────────────────────────

src/vs/platform/agentHost/node/agentService.ts

@@ -1781,7 +1781,7 @@ export class AgentService extends Disposable implements IAgentService {
 			descriptor,
 			subscribers: 1,
 			disposables,
-			pendingGc: new MutableDisposable(),
+			pendingGc: disposables.add(new MutableDisposable()),
 			dispose: () => disposables.dispose(),
 		});
 		return descriptor;

src/vs/platform/agentHost/test/common/agentHostFileSystemProvider.test.ts

@@ -588,10 +588,14 @@ suite('AgentHostFileSystemProvider - resolve / mkdir / copy / watch', () => {
 		assert.strictEqual(connection.watchCalls[0].recursive, true);
 		assert.deepStrictEqual(connection.watchCalls[0].excludes, { items: ['**/node_modules/**'] });
 
-		const change: IFileChange = { resource: URI.parse('file:///watched/a.txt'), type: FileChangeType.UPDATED };
-		onDidChange.fire([change]);
+		// When watchResource reports changes from the underlying filesystem,
+		// they come back with file:// URIs. The provider re-encodes them with
+		// the agent host authority.
+		const incomingChange: IFileChange = { resource: URI.parse('file:///watched/a.txt'), type: FileChangeType.UPDATED };
+		const expectedChange: IFileChange = { resource: toAgentHostUri(URI.parse('file:///watched/a.txt'), 'remote'), type: FileChangeType.UPDATED };
+		onDidChange.fire([incomingChange]);
 
-		assert.deepStrictEqual(received, [[change]]);
+		assert.deepStrictEqual(received, [[expectedChange]]);
 
 		watchDisposable.dispose();
 		assert.strictEqual(handleDisposed, true, 'underlying handle should be disposed when wrapper is disposed');

src/vs/platform/agentHost/test/node/protocolServerHandler.test.ts

@@ -12,7 +12,7 @@ import { ensureNoDisposablesAreLeakedInTestSuite } from '../../../../base/test/c
 import { NullLogService } from '../../../log/common/log.js';
 import { FileType } from '../../../files/common/files.js';
 import { type IAgentCreateSessionConfig, type IAgentResolveSessionConfigParams, type IAgentService, type IAgentSessionConfigCompletionsParams, type IAgentSessionMetadata, type AuthenticateParams, type AuthenticateResult } from '../../common/agentService.js';
-import { CompletionsParams, CompletionsResult, ListSessionsResult, ResourceReadResult, ResolveSessionConfigResult, SessionConfigCompletionsResult } from '../../common/state/protocol/commands.js';
+import { CompletionsParams, CompletionsResult, ListSessionsResult, ResourceReadResult, ResolveSessionConfigResult, SessionConfigCompletionsResult, ResourceMkdirParams, ResourceMkdirResult, ResourceResolveParams, ResourceResolveResult, ResourceCopyParams, ResourceCopyResult } from '../../common/state/protocol/commands.js';
 import { ActionType, type IRootConfigChangedAction, type SessionAction, type TerminalAction } from '../../common/state/sessionActions.js';
 import { PROTOCOL_VERSION } from '../../common/state/protocol/version/registry.js';
 import { isJsonRpcNotification, isJsonRpcRequest, isJsonRpcResponse, JSON_RPC_INTERNAL_ERROR, ProtocolError, AHP_UNSUPPORTED_PROTOCOL_VERSION, type AhpNotification, type InitializeResult, type ProtocolMessage, type ReconnectResult, type ResourceListResult, type ResourceWriteParams, type ResourceWriteResult, type IStateSnapshot } from '../../common/state/sessionProtocol.js';
@@ -145,11 +145,11 @@ class MockAgentService implements IAgentService {
 	async resourceRead(_uri: URI): Promise<ResourceReadResult> {
 		throw new Error('Not implemented');
 	}
-	async resourceCopy(): Promise<{}> { return {}; }
+	async resourceCopy(_params: ResourceCopyParams): Promise<ResourceCopyResult> { return {}; }
 	async resourceDelete(): Promise<{}> { return {}; }
 	async resourceMove(): Promise<{}> { return {}; }
-	async resourceResolve(): Promise<any> { throw new Error('Not implemented'); }
-	async resourceMkdir(): Promise<{}> { return {}; }
+	async resourceResolve(_params: ResourceResolveParams): Promise<ResourceResolveResult> { throw new Error('Not implemented'); }
+	async resourceMkdir(_params: ResourceMkdirParams): Promise<ResourceMkdirResult> { return {}; }
 	readonly watchSubscribeCalls: string[] = [];
 	readonly watchUnsubscribeCalls: string[] = [];
 	/** Channels for which `onResourceWatchSubscribed` should return a descriptor. */

src/vs/workbench/contrib/terminal/test/browser/agentHostPty.test.ts

@@ -13,11 +13,12 @@ import { ActionType, StateAction } from '../../../../../platform/agentHost/commo
 import { RootState, TerminalClaimKind, type TerminalState } from '../../../../../platform/agentHost/common/state/protocol/state.js';
 import type { CompletionsParams, CompletionsResult, CreateTerminalParams, ResolveSessionConfigResult, SessionConfigCompletionsResult } from '../../../../../platform/agentHost/common/state/protocol/commands.js';
 import type { ActionEnvelope, IRootConfigChangedAction, SessionAction, TerminalAction, INotification } from '../../../../../platform/agentHost/common/state/sessionActions.js';
-import type { ResourceCopyParams, ResourceCopyResult, ResourceDeleteParams, ResourceDeleteResult, ResourceListResult, ResourceMoveParams, ResourceMoveResult, ResourceReadResult, ResourceWriteParams, ResourceWriteResult } from '../../../../../platform/agentHost/common/state/sessionProtocol.js';
+import type { ResourceCopyParams, ResourceCopyResult, ResourceDeleteParams, ResourceDeleteResult, ResourceListResult, ResourceMoveParams, ResourceMoveResult, ResourceReadResult, ResourceResolveParams, ResourceResolveResult, ResourceWriteParams, ResourceWriteResult, CreateResourceWatchParams, CreateResourceWatchResult, ResourceMkdirParams, ResourceMkdirResult } from '../../../../../platform/agentHost/common/state/sessionProtocol.js';
 
 import { AgentHostPty } from '../../browser/agentHostPty.js';
 import { IAgentSubscription } from '../../../../../platform/agentHost/common/state/agentSubscription.js';
 import { StateComponents } from '../../../../../platform/agentHost/common/state/sessionState.js';
+import type { IRemoteWatchHandle } from '../../../../../platform/agentHost/common/agentHostFileSystemProvider.js';
 // ---- Mock IAgentConnection --------------------------------------------------
 
 class MockAgentConnection implements IAgentConnection {
@@ -78,10 +79,10 @@ class MockAgentConnection implements IAgentConnection {
 	async resourceCopy(_params: ResourceCopyParams): Promise<ResourceCopyResult> { return {}; }
 	async resourceDelete(_params: ResourceDeleteParams): Promise<ResourceDeleteResult> { return {}; }
 	async resourceMove(_params: ResourceMoveParams): Promise<ResourceMoveResult> { return {}; }
-	async resourceResolve(_params: any): Promise<any> { throw new Error('Not implemented'); }
-	async resourceMkdir(_params: any): Promise<any> { return {}; }
-	async createResourceWatch(_params: any): Promise<any> { throw new Error('Not implemented'); }
-	async watchResource(_params: any): Promise<any> { throw new Error('Not implemented'); }
+	async resourceResolve(_params: ResourceResolveParams): Promise<ResourceResolveResult> { throw new Error('Not implemented'); }
+	async resourceMkdir(_params: ResourceMkdirParams): Promise<ResourceMkdirResult> { return {}; }
+	async createResourceWatch(_params: CreateResourceWatchParams): Promise<CreateResourceWatchResult> { throw new Error('Not implemented'); }
+	async watchResource(_params: CreateResourceWatchParams): Promise<IRemoteWatchHandle> { throw new Error('Not implemented'); }
 
 	// ---- IAgentConnection new API (stubs for tests) -----
 	readonly rootState: IAgentSubscription<RootState> = {