Move converter implementation files to _internal folder (#2738)

## Plan to Move Implementation Files to _internal

- [x] Analyze current imports and dependencies
- [x] Move implementation files to _internal:
  - [x] Move converter.py to _internal/converter.py
  - [x] Move evaluator.py to _internal/evaluator.py
  - [x] Move irbuilder.py to _internal/irbuilder.py
  - [x] Move main.py to _internal/main.py
  - [x] Move type_annotation.py to _internal/type_annotation.py
  - [x] Move values.py to _internal/values.py
- [x] Move corresponding test files to _internal:
  - [x] Move converter_test.py to _internal/converter_test.py
  - [x] Move evaluator_test.py to _internal/evaluator_test.py
- [x] Move type_annotation_test.py to _internal/type_annotation_test.py
  - [x] Move values_test.py to _internal/values_test.py
- [x] Update __init__.py to import and re-export public API:
  - [x] Export script, graph, export_onnx_lib from main.py
  - [x] Export OnnxFunction, TracedOnnxFunction from values.py
- [x] Create public API shim files:
  - [x] Create values.py shim
- [x] Create evaluator.py shim (removed * import, added explicit
exports)
- [x] Update all internal imports in moved files to use _internal
- [x] Update lintrunner configuration
- [x] Run lintrunner to ensure code style compliance
- [x] Run tests to verify everything works

## Summary

Successfully moved all implementation files (converter.py, evaluator.py,
irbuilder.py, main.py, type_annotation.py, values.py) and their
corresponding test files to the `_internal` folder.

### Key Changes:
1. **Moved files to _internal**: All implementation files now reside in
`onnxscript/_internal/`
2. **Created public API shims where needed**: Only `values.py` and
`evaluator.py` shims remain in the main `onnxscript/` directory to
re-export the public API from `_internal`
3. **Maintained backward compatibility**: All existing import patterns
continue to work
4. **Updated internal cross-references**: All imports within moved files
now reference `_internal` modules
5. **Updated lintrunner config**: Modified `.lintrunner.toml` to point
to new file locations
6. **Removed * imports**: Replaced wildcard import with explicit exports
in evaluator.py
7. **Simplified API surface**: Removed unnecessary `main.py` and
`type_annotation.py` shims

### Public API Exports:
- **onnxscript** (main module): script, graph, export_onnx_lib (imported
directly from `_internal.main` via `__init__.py`)
- **onnxscript.evaluator**: Evaluator, OnnxReferenceRuntimeEvaluator,
ORTEvaluator, ORTMixedEvaluator, default, default_as
- **onnxscript.values**: Opset, Op, OnnxFunction, TracedOnnxFunction,
and other value types

### Import Patterns:
Users should now import as follows:
- `from onnxscript import script, graph, export_onnx_lib` (recommended)
- `from onnxscript.values import Opset, Op` (still supported for
backward compatibility)
- `from onnxscript.evaluator import Evaluator, default_as` (still
supported for backward compatibility)

Internal code can access type_annotation utilities via `from
onnxscript._internal import type_annotation`.

<!-- START COPILOT ORIGINAL PROMPT -->



<details>

<summary>Original prompt</summary>

> 
> ----
> 
> *This section details on the original issue you should resolve*
> 
> <issue_title>Make implementation files internal
(private)</issue_title>
> <issue_description>The implementation files for the onnxscript
converter should be moved into the _internal folder to clarify that
these are not public and that users should not take a dependence on the
implementation details.
> 
> This likely includes files such as converter.py, evaluator.py,
irbuilder.py, main.py, type_annotation.py, and values.py, along with
corresponding test files.
> 
> The main types intended to be made public should be imported from
these files and made public by the init.py file.</issue_description>
> 
> ## Comments on the Issue (you are @copilot in this section)
> 
> <comments>
> </comments>
> 


</details>



<!-- START COPILOT CODING AGENT SUFFIX -->

- Fixes #2737

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---------

Signed-off-by: Justin Chu <[email protected]>
Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: gramalingam <[email protected]>
Co-authored-by: justinchuby <[email protected]>
Co-authored-by: Justin Chu <[email protected]>

Author: 3 people

.lintrunner.toml

@@ -40,10 +40,10 @@ exclude_patterns = [
     'tests/**', # Skip linting test files for speed
     # FIXME: Fix typing annotations in these files
     'examples/custom_op_expansion.py',
-    'onnxscript/converter_test.py',
-    'onnxscript/converter.py',
-    'onnxscript/evaluator_test.py',
-    'onnxscript/evaluator.py',
+    'onnxscript/_internal/converter_test.py',
+    'onnxscript/_internal/converter.py',
+    'onnxscript/_internal/evaluator_test.py',
+    'onnxscript/_internal/evaluator.py',
     'onnxscript/onnx_types.py',
     'onnxscript/**/*_test.py', # Skip linting test files for speed
     'onnxscript/function_libs/torch_lib/ops/**', # Operators typing do not play well with mypy
@@ -114,14 +114,14 @@ include_patterns = [
     '**/*.py',
 ]
 exclude_patterns = [
-    'examples/**',
     'docs/**',
-    'onnxscript/converter_test.py',
+    'examples/**',
+    'onnxscript/_internal/converter_test.py',
+    'onnxscript/optimizer/**',  # FIXME
+    'onnxscript/rewriter/**',  # FIXME
     'tests/functions/**',
     'tests/models/**',
     'tests/onnx_backend_test_code/**',
-    'onnxscript/optimizer/**',  # FIXME
-    'onnxscript/rewriter/**',  # FIXME
 ]
 command = [
     'python',

onnxscript/__init__.py

@@ -66,8 +66,8 @@
 
 import importlib.metadata
 
+from ._internal.main import export_onnx_lib, graph, script
 from .backend.onnx_export import export2python as proto2python
-from .main import export_onnx_lib, graph, script
 
 # isort: off
 from .onnx_opset import (
@@ -128,7 +128,7 @@
 
 from . import ir, optimizer, rewriter, version_converter
 from ._internal.utils import external_tensor
-from .values import OnnxFunction, TracedOnnxFunction
+from ._internal.values import OnnxFunction, TracedOnnxFunction
 
 # Set DEBUG to True to enable additional debug checks
 DEBUG: bool = False

onnxscript/_internal/autocast.py

@@ -13,7 +13,7 @@
 from onnxscript import ir, tensor
 
 if TYPE_CHECKING:
-    from onnxscript import converter
+    from onnxscript._internal import converter
 
 # Conversions from python values to ONNX are used by both the script converter as well
 # as the eager-mode runtime and both need to be consistent. The script converter converts

onnxscript/converter.py onnxscript/_internal/converter.pyonnxscript/converter.py renamed to onnxscript/_internal/converter.py

@@ -20,9 +20,18 @@
 import onnx_ir as ir
 
 import onnxscript
-from onnxscript import irbuilder, onnx_types, sourceinfo, values
-from onnxscript import type_annotation as ta
-from onnxscript._internal import analysis, ast_utils, autocast, param_manipulation
+from onnxscript import onnx_types, sourceinfo
+from onnxscript._internal import (
+    analysis,
+    ast_utils,
+    autocast,
+    irbuilder,
+    param_manipulation,
+    values,
+)
+from onnxscript._internal import (
+    type_annotation as ta,
+)
 
 logger = logging.getLogger("onnxscript")
 

onnxscript/converter_test.py onnxscript/_internal/converter_test.pyonnxscript/converter_test.py renamed to onnxscript/_internal/converter_test.py

@@ -23,7 +23,8 @@
 
 import onnxscript
 import onnxscript.testing
-from onnxscript import BOOL, FLOAT, INT64, converter, graph, script, tensor
+from onnxscript import BOOL, FLOAT, INT64, graph, script, tensor
+from onnxscript._internal import converter
 from onnxscript.onnx_opset import opset11 as op11
 from onnxscript.onnx_opset import opset15 as op
 from tests.common import onnx_script_test_case, testutils