# Buggy code
def _parse_line(self, line):
    """Parse a line from a host file.

    Args:
        line: The bytes object to parse.

    Returns:
        True if parsing succeeded, False otherwise.
    """
    if line.startswith(b"#"):
        # Ignoring comments early so we don't have to care about
        # encoding errors in them.
        return True

    try:
        line = line.decode("utf-8")
    except UnicodeDecodeError:
        log.misc.error("Failed to decode: {!r}".format(line))
        return False

    # Remove comments
    try:
        hash_idx = line.index("#")
        line = line[:hash_idx]
    except ValueError:
        pass

    line = line.strip()
    # Skip empty lines
    if not line:
        return True

    parts = line.split()
    if len(parts) == 1:
        # "one host per line" format
        host = parts[0]
    elif len(parts) == 2:
        # /etc/hosts format
        host = parts[1]
    else:
        log.misc.error("Failed to parse: {!r}".format(line))
        return False

    if host not in self.WHITELISTED:
        self._blocked_hosts.add(host)

    return True


# Traceback (ValueError)
16:39:44 DEBUG    init       app:_init_modules:468 Initializing websettings...
16:39:45 ERROR    misc       crashsignal:exception_hook:216 Uncaught exception
Traceback (most recent call last):
File "/bin/qutebrowser", line 11, in <module>
load_entry_point('qutebrowser==1.1.1', 'gui_scripts', 'qutebrowser')()
File "/usr/lib/python3.6/site-packages/qutebrowser/qutebrowser.py", line 188, in main
return app.run(args)
File "/usr/lib/python3.6/site-packages/qutebrowser/app.py", line 137, in run
init(args, crash_handler)
File "/usr/lib/python3.6/site-packages/qutebrowser/app.py", line 163, in init
_init_modules(args, crash_handler)
File "/usr/lib/python3.6/site-packages/qutebrowser/app.py", line 469, in _init_modules
websettings.init(args)
File "/usr/lib/python3.6/site-packages/qutebrowser/config/websettings.py", line 215, in init
webenginesettings.init(args)
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/webenginesettings.py", line 297, in init
websettings.init_mappings(MAPPINGS)
File "/usr/lib/python3.6/site-packages/qutebrowser/config/websettings.py", line 198, in init_mappings
mapping.set(value)
File "/usr/lib/python3.6/site-packages/qutebrowser/config/websettings.py", line 72, in set
self._set(value, settings=settings)
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/webenginesettings.py", line 154, in _set
filenames = [self._find_installed(code) for code in value]
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/webenginesettings.py", line 154, in <listcomp>
filenames = [self._find_installed(code) for code in value]
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/webenginesettings.py", line 143, in _find_installed
local_filename = spell.local_filename(code)
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/spell.py", line 64, in local_filename
all_installed = local_files(code)
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/spell.py", line 51, in local_files
for matching_dict in sorted(matching_dicts, key=version, reverse=True):
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/spell.py", line 36, in version
.format(filename))
ValueError: the given dictionary file name is malformed: /usr/share/qt/qtwebengine_dictionaries/en-US.bdic

# Fixed code
def _parse_line(self, line):
    """Parse a line from a host file.

    Args:
        line: The bytes object to parse.

    Returns:
        True if parsing succeeded, False otherwise.
    """
    if line.startswith(b"#"):
        # Ignoring comments early so we don't have to care about
        # encoding errors in them.
        return True

    try:
        line = line.decode("utf-8")
    except UnicodeDecodeError:
        log.misc.error("Failed to decode: {!r}".format(line))
        return False

    # Remove comments
    try:
        hash_idx = line.index("#")
        line = line[:hash_idx]
    except ValueError:
        pass

    line = line.strip()
    # Skip empty lines
    if not line:
        return True

    parts = line.split()
    if len(parts) == 1:
        # "one host per line" format
        hosts = [parts[0]]
    else:
        # /etc/hosts format
        hosts = parts[1:]

    for host in hosts:
        if "." in host and not host.endswith(".localdomain"):
            self._blocked_hosts.add(host)

    return True