Respect locked provider fallback

Author: lintowe

apps/web/src/providerInstances.test.ts

@@ -4,6 +4,7 @@ import {
   deriveProviderInstanceEntries,
   resolveSelectableProviderInstance,
   resolveProviderDriverKindForInstanceSelection,
+  resolveSelectedProviderInstanceId,
 } from "./providerInstances";
 
 function provider(input: {
@@ -130,3 +131,22 @@ describe("resolveProviderDriverKindForInstanceSelection", () => {
     ).toBeUndefined();
   });
 });
+
+describe("resolveSelectedProviderInstanceId", () => {
+  it("falls back to the locked provider before the selected provider", () => {
+    const providers = [
+      provider({ provider: ProviderDriverKind.make("codex"), instanceId: "codex" }),
+      provider({ provider: ProviderDriverKind.make("claudeAgent"), instanceId: "claudeAgent" }),
+    ];
+    const entries = deriveProviderInstanceEntries(providers);
+
+    expect(
+      resolveSelectedProviderInstanceId({
+        entries,
+        candidates: [null],
+        selectedProvider: ProviderDriverKind.make("claudeAgent"),
+        lockedProvider: ProviderDriverKind.make("codex"),
+      }),
+    ).toBe("codex");
+  });
+});

apps/web/src/providerInstances.ts

@@ -210,10 +210,11 @@ export function resolveSelectedProviderInstanceId(input: {
     return ProviderInstanceId.make(explicitSelection);
   }
 
+  const fallbackProvider = lockedProvider ?? input.selectedProvider;
   const byKind = input.entries.find(
     (entry) =>
       entry.enabled &&
-      entry.driverKind === input.selectedProvider &&
+      entry.driverKind === fallbackProvider &&
       (!lockedContinuationGroupKey || entry.continuationGroupKey === lockedContinuationGroupKey),
   );
   if (byKind) return byKind.instanceId;