fix (ai): split provider and model ids correctly in the provider registry (#2057)

Author: lgrammel

Diff for: .changeset/hot-starfishes-shake.md

@@ -0,0 +1,5 @@
+---
+'ai': patch
+---
+
+fix (ai): split provider and model ids correctly in the provider registry

Diff for: packages/core/core/registry/provider-registry.test.ts

@@ -21,10 +21,25 @@ describe('languageModel', () => {
     expect(modelRegistry.languageModel('provider:model')).toEqual(model);
   });
 
+  it('should return language model with additional colon from provider', () => {
+    const model = new MockLanguageModelV1();
+
+    const modelRegistry = experimental_createProviderRegistry({
+      provider: {
+        languageModel: id => {
+          expect(id).toEqual('model:part2');
+          return model;
+        },
+      },
+    });
+
+    expect(modelRegistry.languageModel('provider:model:part2')).toEqual(model);
+  });
+
   it('should throw NoSuchProviderError if provider does not exist', () => {
     const registry = experimental_createProviderRegistry({});
 
-    expect(() => registry.languageModel('provider:model')).toThrowError(
+    expect(() => registry.languageModel('provider:model:part2')).toThrowError(
       NoSuchProviderError,
     );
   });

Diff for: packages/core/core/registry/provider-registry.ts

@@ -97,11 +97,13 @@ class DefaultProviderRegistry implements experimental_ProviderRegistry {
   }
 
   private splitId(id: string): [string, string] {
-    if (!id.includes(':')) {
+    const index = id.indexOf(':');
+
+    if (index === -1) {
       throw new InvalidModelIdError({ id });
     }
 
-    return id.split(':') as [string, string];
+    return [id.slice(0, index), id.slice(index + 1)];
   }
 
   languageModel(id: string): LanguageModel {