139 lines
3.6 KiB
Python
Executable file
139 lines
3.6 KiB
Python
Executable file
#!/usr/bin/env python3
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import re
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import sys
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def filter_change_block(
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change_lines: list[str], search: str, replace: str
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) -> list[str]:
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removed_lines = []
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added_lines = []
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phase = "minus"
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for line in change_lines:
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if line.startswith("-"):
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if phase != "minus":
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raise ValueError(
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"Non-consecutive '-' and '+' lines in change block."
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)
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removed_lines.append(line[1:])
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continue
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if line.startswith("+"):
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phase = "plus"
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added_lines.append(line[1:])
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continue
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raise ValueError("Unexpected non-change line in change block.")
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transformed_removed = [
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re.sub(search, replace, line) for line in removed_lines
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]
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if transformed_removed == added_lines:
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return change_lines
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if len(removed_lines) != len(added_lines):
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return []
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kept_lines = []
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for removed, added in zip(removed_lines, added_lines):
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if re.sub(search, replace, removed) == added:
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kept_lines.append(f"-{removed}")
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kept_lines.append(f"+{added}")
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else:
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kept_lines.append(f" {removed}")
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if not kept_lines:
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return []
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return kept_lines
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def filter_hunk(
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hunk_lines: list[str], search: str, replace: str
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) -> list[str]:
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if not hunk_lines:
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return []
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header = hunk_lines[0]
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body = hunk_lines[1:]
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output_body: list[str] = []
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i = 0
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while i < len(body):
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line = body[i]
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if line.startswith(("+", "-")):
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block = []
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while i < len(body) and body[i].startswith(("+", "-")):
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block.append(body[i])
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i += 1
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kept_block = filter_change_block(block, search, replace)
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if kept_block:
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output_body.extend(kept_block)
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continue
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output_body.append(line)
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i += 1
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if not any(line.startswith(("+", "-")) for line in output_body):
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return []
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return [header] + output_body
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def main() -> None:
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if len(sys.argv) != 3:
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raise SystemExit("Usage: mechanicaldiff <search> <replace>")
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search = sys.argv[1]
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replace = sys.argv[2]
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input_data = sys.stdin.read()
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lines = input_data.splitlines(keepends=True)
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preamble_lines = []
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sections = []
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current = None
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for line in lines:
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if line.startswith("diff --git "):
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if current is not None:
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sections.append(current)
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current = {"header": [line], "hunks": []}
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continue
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if current is None:
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preamble_lines.append(line)
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continue
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if line.startswith("@@ "):
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current["hunks"].append([line])
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else:
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if current["hunks"]:
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current["hunks"][-1].append(line)
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else:
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current["header"].append(line)
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if current is not None:
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sections.append(current)
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output_lines = []
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output_lines.extend(preamble_lines)
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for section in sections:
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kept_hunks = []
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for hunk_lines in section["hunks"]:
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filtered = filter_hunk(hunk_lines, search, replace)
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if filtered:
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kept_hunks.append(filtered)
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if not kept_hunks:
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continue
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output_lines.extend(section["header"])
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for hunk_lines in kept_hunks:
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output_lines.extend(hunk_lines)
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output_data = "".join(output_lines)
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sys.stdout.write(output_data)
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if output_data != input_data:
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raise SystemExit(1)
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if __name__ == "__main__":
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main()
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