def extract_relevant_diff()

in bugbug/tools/comment_resolver.py [0:0]

• 82 lines of code
• 17 McCabe index (conditional complexity)

def extract_relevant_diff(patch_diff, filename, start_line, end_line, hunk_size):
    file_diff_pattern = rf"diff --git a/{re.escape(filename)} b/{re.escape(filename)}\n.*?(?=\ndiff --git|$)"
    match = re.search(file_diff_pattern, patch_diff, re.DOTALL)

    if match:
        hunk_header_pattern = r"@@ -(\d+),(\d+) \+(\d+),(\d+) @@"
        match2 = re.finditer(hunk_header_pattern, match.group(0))
        first_index = None
        last_index = None

        for m in match2:
            diff_lines = match.group(0).split("\n")

            deletion_start_line = int(m.group(1))
            deletion_num_lines = int(m.group(2))
            addition_start_line = int(m.group(3))
            addition_num_lines = int(m.group(4))

            if (
                start_line < deletion_start_line and start_line < addition_start_line
            ) or (
                start_line > (deletion_start_line + deletion_num_lines)
                and start_line > (addition_start_line + addition_num_lines)
            ):
                continue

            added_lines = []
            deleted_lines = []

            for line in diff_lines[diff_lines.index(m.group()) + 1 :]:
                if line.startswith("-"):
                    deleted_lines.append(line)
                elif line.startswith("+"):
                    added_lines.append(line)

            if not deleted_lines or not added_lines:
                logger.error(f"No deleted or added lines found for file: {filename}")
                return None

            deletion_start_diff_line = deleted_lines[
                min(
                    len(deleted_lines) - 1,
                    max(0, start_line - deletion_start_line - hunk_size),
                )
            ]
            deletion_end_diff_line = deleted_lines[
                max(
                    0,
                    min(
                        len(deleted_lines) - 1,
                        end_line - deletion_start_line + hunk_size,
                    ),
                )
            ]

            addition_start_diff_line = added_lines[
                min(
                    len(added_lines) - 1,
                    max(0, start_line - addition_start_line - hunk_size),
                )
            ]
            addition_end_diff_line = added_lines[
                max(
                    0,
                    min(
                        len(added_lines) - 1, end_line - addition_start_line + hunk_size
                    ),
                )
            ]

            first_index = None
            last_index = None

            diff_lines = match.group(0).split("\n")

            for i, line in enumerate(diff_lines):
                if line in [
                    deletion_start_diff_line,
                    deletion_end_diff_line,
                    addition_start_diff_line,
                    addition_end_diff_line,
                ]:
                    if first_index is None:
                        first_index = i
                    last_index = i

        if first_index is not None and last_index is not None:
            relevant_diff = "\n".join(diff_lines[first_index : last_index + 1])
            return relevant_diff
        else:
            logger.error(f"No relevant diff found for lines: {start_line}-{end_line}")
            return None
    else:
        logger.error(f"No diff found for file: {filename}")
        return None