Fix: Handle no valid python files in the directory. (#83)

If you run torchfix script on a directory without Python files, it will
terminate with an error. This modifies the script to just do nothing in
such cases, without terminating with an error.


### Testing:
Added test "test_no_python_files"

### Without fix the new test fails:
   assert 1 == 0
...... raise Exception("Must have at least one job to
process!")\nException: Must have at least one job to
process!\n').returncode ......

tests/test_torchfix.py

@@ -1,16 +1,18 @@
+import logging
+import subprocess
 from pathlib import Path
+
+import libcst.codemod as codemod
 from torchfix.torchfix import (
-    TorchChecker,
-    TorchCodemod,
-    TorchCodemodConfig,
     DISABLED_BY_DEFAULT,
     expand_error_codes,
-    GET_ALL_VISITORS,
     GET_ALL_ERROR_CODES,
+    GET_ALL_VISITORS,
     process_error_code_str,
+    TorchChecker,
+    TorchCodemod,
+    TorchCodemodConfig,
 )
-import logging
-import libcst.codemod as codemod
 
 FIXTURES_PATH = Path(__file__).absolute().parent / "fixtures"
 LOGGER = logging.getLogger(__name__)
@@ -103,3 +105,18 @@ def test_errorcodes_distinct():
 
 def test_parse_error_code_str(case, expected):
     assert process_error_code_str(case) == expected
+
+
+def test_no_python_files(tmp_path):
+    # Create a temporary directory with no Python files
+    non_python_file = tmp_path / "not_a_python_file.txt"
+    non_python_file.write_text("This is not a Python file")
+
+    # Run torchfix on the temporary directory
+    result = subprocess.run(
+        ["python3", "-m", "torchfix", str(tmp_path)],
+        capture_output=True,
+        text=True,
+    )
+    # Check that the script exits successfully
+    assert result.returncode == 0

torchfix/__main__.py

@@ -1,20 +1,22 @@
 import argparse
-import libcst.codemod as codemod
 
 import contextlib
 import ctypes
-import sys
 import io
+import sys
+
+import libcst.codemod as codemod
+
+from .common import CYAN, ENDC
 
 from .torchfix import (
-    TorchCodemod,
-    TorchCodemodConfig,
     __version__ as TorchFixVersion,
     DISABLED_BY_DEFAULT,
     GET_ALL_ERROR_CODES,
     process_error_code_str,
+    TorchCodemod,
+    TorchCodemodConfig,
 )
-from .common import CYAN, ENDC
 
 
 # Should get rid of this code eventually.
@@ -83,7 +85,6 @@ def _parse_args() -> argparse.Namespace:
 
 def main() -> None:
     args = _parse_args()
-
     files = codemod.gather_files(args.path)
 
     # Filter out files that don't have "torch" string in them.
@@ -97,6 +98,8 @@ def main() -> None:
                     torch_files.append(file)
                     break
 
+    if not torch_files:
+        return
     config = TorchCodemodConfig()
     config.select = list(process_error_code_str(args.select))
     command_instance = TorchCodemod(codemod.CodemodContext(), config)