Function write_file

mypyc/build.py:425–450

Write data into a file. If the file already exists and has the same contents we want to write, skip writing so as to preserve the mtime and avoid triggering recompilation.

(path: str, contents: str)

def write_file(path: str, contents: str) -> None:
    """Write data into a file.

    If the file already exists and has the same contents we
    want to write, skip writing so as to preserve the mtime
    and avoid triggering recompilation.
    """
    # We encode it ourselves and open the files as binary to avoid windows
    # newline translation
    encoded_contents = contents.encode("utf-8")
    try:
        with open(path, "rb") as f:
            old_contents: bytes | None = f.read()
    except OSError:
        old_contents = None
    if old_contents != encoded_contents:
        os.makedirs(os.path.dirname(path), exist_ok=True)
        with open(path, "wb") as g:
            g.write(encoded_contents)

        # Fudge the mtime forward because otherwise when two builds happen close
        # together (like in a test) setuptools might not realize the source is newer
        # than the new artifact.
        # XXX: This is bad though.
        new_mtime = os.stat(path).st_mtime + 1
        os.utime(path, times=(new_mtime, new_mtime))


_MYPYC_EXTENSION_MARKER = "_mypyc_skip_redundant_inplace_copy"