Mysterious “embedded null byte” error

Question

Working on a fairly large/complex Django project with a team, we occasionally see runserver crash with ValueError: embedded null byte. We restart runserver and

Answer 1

• One of the AppConfig objects has null byte in its path attribute.
• One of the LOCALE_PATHS has null byte.
• One of the files is in the "wrong" encoding, so Django treats something has null byte (e. g. AppConfig.path).
• One of the files or directories in project directory has null byte (\x00) in its name.
• Other reason.

autoreload.py lines related to this issue. os.path.isdir() raises ValueError: embedded null byte if its argument has null byte, e. g. os.path.isdir('foo\x00bar').

You can try to edit autoreload.py, comment out these lines temporarily:

basedirs = [os.path.abspath(basedir) for basedir in basedirs
            if os.path.isdir(basedir)]

and add this:

temp_basedirs = []
for basedir in basedirs:
    try:
        if os.path.isdir(basedir):
            temp_basedirs.append(os.path.abspath(basedir))
    except ValueError:
        print(basedir)
        raise
basedirs = temp_basedirs