fix: typebuilder imports (#2209)

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> [!IMPORTANT]
> Fix import issues in TypeBuilder files and add tests to verify correct
imports and functionality.
> 
>   - **Imports**:
> - Add imports for `FieldType`, `EnumValueBuilder`, `EnumBuilder`, and
`ClassBuilder` in `type_builder.py.j2` and `type_builder.ts.j2`.
> - Export `FieldType`, `EnumBuilder`, and `ClassBuilder` in
`type_builder.ts.j2` and `type_builder.ts` in `typescript-esm` and
`typescript`.
>   - **Tests**:
> - Add `test_typebuilder_and_fieldtype_imports` in
`test_typebuilder.py` to verify imports of `TypeBuilder` and
`FieldType`.
> - Add import tests in `dynamic-types.test.ts` to ensure `TypeBuilder`
and `FieldType` are correctly imported and functional.
> 
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Author: ba11b0y

engine/generators/languages/python/src/_templates/type_builder.py.j2

@@ -1,6 +1,8 @@
 import typing
 from baml_py import type_builder
 from baml_py import baml_py
+# These are exports, not used here, hence the linter is disabled
+from baml_py.baml_py import FieldType, EnumValueBuilder, EnumBuilder, ClassBuilder # noqa: F401 # pylint: disable=unused-import
 from .globals import DO_NOT_USE_DIRECTLY_UNLESS_YOU_KNOW_WHAT_YOURE_DOING_RUNTIME
 
 class TypeBuilder(type_builder.TypeBuilder):

engine/generators/languages/typescript/src/_templates/type_builder.ts.j2

@@ -2,6 +2,8 @@ import { FieldType } from '@boundaryml/baml/native'
 import { TypeBuilder as _TypeBuilder, EnumBuilder, EnumViewer, ClassBuilder, ClassViewer } from '@boundaryml/baml/type_builder'
 import { DO_NOT_USE_DIRECTLY_UNLESS_YOU_KNOW_WHAT_YOURE_DOING_RUNTIME } from "./globals"
 
+export { FieldType, EnumBuilder, ClassBuilder }
+
 export default class TypeBuilder {
     private tb: _TypeBuilder;
     {% for cls in classes %}

integ-tests/python-v1/baml_client/type_builder.py

@@ -524,3 +524,22 @@ async def test_referencing_existing_class_types():
     tb = TypeBuilder()
     # useful for adding dynamic tools for example
     tb.Person.add_property("props", tb.union([tb.Resume.type(), tb.Hobby.type()]))
+
+
+def test_typebuilder_and_fieldtype_imports():
+    """Test that both TypeBuilder and FieldType can be imported from baml_client.type_builder"""
+    # Test importing both from the same module
+    from baml_client.type_builder import TypeBuilder, FieldType
+    
+    # Verify TypeBuilder works
+    tb = TypeBuilder()
+    assert tb is not None
+    assert isinstance(tb, TypeBuilder)
+    
+    # Verify FieldType is available
+    assert FieldType is not None
+    
+    # Test that TypeBuilder methods return FieldType instances
+    string_type = tb.string()
+    assert isinstance(string_type, FieldType)
+

integ-tests/python/baml_client/type_builder.py

@@ -1,7 +1,25 @@
 import TypeBuilder from "../baml_client/type_builder";
+import { FieldType } from "../baml_client/type_builder";
 import { b } from "./test-setup";
 
 describe("Dynamic Type Tests", () => {
+  describe("Import Tests", () => {
+    it("should import TypeBuilder and FieldType from type_builder module", () => {
+      // Test that TypeBuilder is importable
+      const tb = new TypeBuilder();
+      expect(tb).toBeInstanceOf(TypeBuilder);
+      
+      // Test that FieldType is importable and works
+      expect(FieldType).toBeDefined();
+      
+      // Test that TypeBuilder methods return FieldType instances
+      const stringType = tb.string();
+      // TypeScript will ensure type safety at compile time
+      // This test verifies runtime behavior
+      expect(stringType).toBeDefined();
+    });
+  });
+
   describe("Basic Dynamic Types", () => {
     it("should work with dynamic types single", async () => {
       let tb = new TypeBuilder();