fix(extensions): restored provider unregistration

Added the upstream unregisterProvider lifecycle to queued and initialized extension runtimes. Provider removal now clears runtime model/auth state before replacement, while failed factories restore the prior registration queue.

Fixes #7914

packages/coding-agent/src/config/model-registry.ts

@@ -65,7 +65,7 @@ const BUILT_IN_DISCOVERY_CACHE_TTL_MS = 2 * 60 * 60 * 1000;
 const BUILT_IN_DISCOVERY_NON_AUTHORITATIVE_RETRY_MS = 5 * 60 * 1000;
 
 import type { ApiKeyResolver, FetchImpl } from "@oh-my-pi/pi-ai";
-import { registerOAuthProvider, unregisterOAuthProviders } from "@oh-my-pi/pi-ai/oauth";
+import { registerOAuthProvider, unregisterOAuthProvider, unregisterOAuthProviders } from "@oh-my-pi/pi-ai/oauth";
 import type { OAuthCredentials, OAuthLoginCallbacks } from "@oh-my-pi/pi-ai/oauth/types";
 import { setCodexAttestationProvider } from "@oh-my-pi/pi-ai/providers/openai-codex-responses";
 import { getProviderDefinition } from "@oh-my-pi/pi-ai/registry";
@@ -2514,6 +2514,26 @@ export class ModelRegistry {
 		this.#reloadStaticModels();
 	}
 
+	/**
+	 * Remove one extension-registered provider and restore its static models.
+	 */
+	unregisterProvider(providerName: string): void {
+		const sourceId = this.#runtimeProviderSourceByName.get(providerName);
+		if (sourceId) {
+			const sourceProviders = this.#runtimeProvidersBySource.get(sourceId);
+			sourceProviders?.delete(providerName);
+			if (sourceProviders?.size === 0) {
+				this.#runtimeProvidersBySource.delete(sourceId);
+			}
+			this.#runtimeProviderSourceByName.delete(providerName);
+		}
+		unregisterOAuthProvider(providerName);
+		this.#ensureFullSnapshot();
+		this.#clearRuntimeProviderState(providerName);
+		this.#lastStaticLoadMtime = null;
+		this.#reloadStaticModels();
+	}
+
 	/**
 	 * Remove registrations for extension sources that are no longer active.
 	 */

packages/coding-agent/src/extensibility/extensions/loader.ts

@@ -73,6 +73,15 @@ export class ExtensionRuntime implements IExtensionRuntime {
 	flagValues = new Map<string, boolean | string>();
 	pendingProviderRegistrations: Array<{ name: string; config: ProviderConfig; sourceId: string }> = [];
 
+	registerProvider(name: string, config: ProviderConfig, sourceId: string): void {
+		this.pendingProviderRegistrations.push({ name, config, sourceId });
+	}
+
+	unregisterProvider(name: string): void {
+		const remaining = this.pendingProviderRegistrations.filter(registration => registration.name !== name);
+		this.pendingProviderRegistrations.splice(0, this.pendingProviderRegistrations.length, ...remaining);
+	}
+
 	sendMessage(): void {
 		throw new ExtensionRuntimeNotInitializedError();
 	}
@@ -290,7 +299,11 @@ class ConcreteExtensionAPI implements ExtensionAPI, IExtensionRuntime {
 	}
 
 	registerProvider(name: string, config: ProviderConfig): void {
-		this.runtime.pendingProviderRegistrations.push({ name, config, sourceId: this.extension.path });
+		this.runtime.registerProvider(name, config, this.extension.path);
+	}
+
+	unregisterProvider(name: string): void {
+		this.runtime.unregisterProvider(name, this.extension.path);
 	}
 }
 
@@ -313,20 +326,24 @@ function createExtension(extensionPath: string, resolvedPath: string): Extension
 
 /**
  * Runs an extension factory with provider registration rollback on failure.
- * Records the number of pending provider registrations before the factory runs,
- * and restores that checkpoint if the factory throws.
+ * Restores the complete registration queue when the factory throws because an
+ * extension may unregister entries queued by an earlier extension.
  */
 async function runExtensionFactory(
 	factory: ExtensionFactory,
 	api: ExtensionAPI,
 	runtime: IExtensionRuntime,
 ): Promise<void> {
-	const providerRegistrationCheckpoint = runtime.pendingProviderRegistrations.length;
+	const providerRegistrationCheckpoint = [...runtime.pendingProviderRegistrations];
 
 	try {
 		await factory(api);
 	} catch (error) {
-		runtime.pendingProviderRegistrations.length = providerRegistrationCheckpoint;
+		runtime.pendingProviderRegistrations.splice(
+			0,
+			runtime.pendingProviderRegistrations.length,
+			...providerRegistrationCheckpoint,
+		);
 		throw error;
 	}
 }

packages/coding-agent/src/extensibility/extensions/runner.ts

@@ -530,6 +530,12 @@ export class ExtensionRunner {
 		this.runtime.setServiceTier = actions.setServiceTier ?? throwUnsupportedServiceTierAction;
 		this.runtime.getSessionName = actions.getSessionName;
 		this.runtime.setSessionName = actions.setSessionName;
+		this.runtime.registerProvider = (name, config, sourceId) => {
+			this.modelRegistry.registerProvider(name, config, sourceId);
+		};
+		this.runtime.unregisterProvider = name => {
+			this.modelRegistry.unregisterProvider(name);
+		};
 
 		// Context actions (required)
 		this.#getModel = contextActions.getModel;

packages/coding-agent/src/extensibility/extensions/types.ts

@@ -1373,6 +1373,14 @@ export interface ExtensionAPI {
 	 */
 	registerProvider(name: string, config: ProviderConfig): void;
 
+	/**
+	 * Unregister a provider previously registered by an extension.
+	 *
+	 * Removes extension-provided models and restores overridden built-in models.
+	 * Has no effect when the provider is not registered.
+	 */
+	unregisterProvider(name: string): void;
+
 	/** Shared event bus for extension communication. */
 	events: EventBus;
 }
@@ -1516,6 +1524,10 @@ export interface ExtensionRuntimeState {
 	flagValues: Map<string, boolean | string>;
 	/** Provider registrations queued during extension loading, processed during session initialization */
 	pendingProviderRegistrations: Array<{ name: string; config: ProviderConfig; sourceId: string }>;
+	/** Queue a provider registration until initialization, then apply it immediately. */
+	registerProvider(name: string, config: ProviderConfig, sourceId: string): void;
+	/** Remove a queued or initialized provider registration. */
+	unregisterProvider(name: string, sourceId: string): void;
 }
 
 /** Action implementations for ExtensionAPI methods. */