class PatchGenerator:
"""Generates unified diff patches for changes"""
def generate_patch(self, original: str, modified: str, file_path: str = "code.py") -> str:
"""Create unified diff patch"""
import difflib
original_lines = original.splitlines(keepends=True)
modified_lines = modified.splitlines(keepends=True)
diff = difflib.unified_diff(
original_lines,
modified_lines,
fromfile=f"a/{file_path}",
tofile=f"b/{file_path}",
lineterm=''
)
return ''.join(diff)
def apply_function_patch(
self,
original_file: str,
function_name: str,
old_function_code: str,
new_function_code: str,
file_path: str = "code.py"
) -> str:
"""
Generate patch for replacing a single function in a file.
Safety: refuses if old_function_code is not found exactly once.
"""
occurrences = original_file.count(old_function_code)
if occurrences != 1:
return (
f"Refused: expected '{function_name}' exactly once, "
f"found {occurrences} times."
)
modified = original_file.replace(old_function_code, new_function_code, 1)
return self.generate_patch(original_file, modified, file_path)
