typing: add trivial type hints to mercurial/ui.py

There's not really a pattern here; it's mostly obvious return types and in a few
cases, obvious parameter types.  Some other "obvious" functions are left out
because of quirks in how the return value for the various config() functions are
inferred cause pytype to complain.

mercurial/ui.py

@@ -20,10 +20,15 b' import sys'
 import traceback
 
 from typing import (
+    Any,
+    Callable,
     Dict,
     List,
+    NoReturn,
     Optional,
     Tuple,
+    Type,
+    TypeVar,
     Union,
     cast,
 )
@@ -57,21 +62,23 b' from .utils import ('
     urlutil,
 )
 
+_ConfigItems = Dict[Tuple[bytes, bytes], object]  # {(section, name) : value}
 # The **opts args of the various write() methods can be basically anything, but
 # there's no way to express it as "anything but str".  So type it to be the
 # handful of known types that are used.
 _MsgOpts = Union[bytes, bool, List["_PromptChoice"]]
 _PromptChoice = Tuple[bytes, bytes]
+_Tui = TypeVar('_Tui', bound="ui")
 
 urlreq = util.urlreq
 
 # for use with str.translate(None, _keepalnum), to keep just alphanumerics
-_keepalnum = b''.join(
+_keepalnum: bytes = b''.join(
     c for c in map(pycompat.bytechr, range(256)) if not c.isalnum()
 )
 
 # The config knobs that will be altered (if unset) by ui.tweakdefaults.
-tweakrc = b"""
+tweakrc: bytes = b"""
 [ui]
 # The rollback command is dangerous. As a rule, don't use it.
 rollback = False
@@ -98,7 +105,7 b' showfunc = 1'
 word-diff = 1
 """
 
-samplehgrcs = {
+samplehgrcs: Dict[bytes, bytes] = {
     b'user': b"""# example user config (see 'hg help config' for more info)
 [ui]
 # name and email, e.g.
@@ -187,7 +194,7 b' def _maybebytesurl(maybestr):'
 class httppasswordmgrdbproxy:
     """Delays loading urllib2 until it's needed."""
 
-    def __init__(self):
+    def __init__(self) -> None:
         self._mgr = None
 
     def _get_mgr(self):
@@ -210,7 +217,7 b' class httppasswordmgrdbproxy:'
         )
 
 
-def _catchterm(*args):
+def _catchterm(*args) -> NoReturn:
     raise error.SignalInterrupt
 
 
@@ -219,11 +226,11 b' def _catchterm(*args):'
 _unset = object()
 
 # _reqexithandlers: callbacks run at the end of a request
-_reqexithandlers = []
+_reqexithandlers: List = []
 
 
 class ui:
-    def __init__(self, src=None):
+    def __init__(self, src: Optional["ui"] = None) -> None:
         """Create a fresh new ui object if no src given
 
         Use uimod.ui.load() to create a ui which knows global and user configs.
@@ -318,13 +325,13 b' class ui:'
                 if k in self.environ:
                     self._exportableenviron[k] = self.environ[k]
 
-    def _new_source(self):
+    def _new_source(self) -> None:
         self._ocfg.new_source()
         self._tcfg.new_source()
         self._ucfg.new_source()
 
     @classmethod
-    def load(cls):
+    def load(cls: Type[_Tui]) -> _Tui:
         """Create a ui and load global and user configs"""
         u = cls()
         # we always trust global config files and environment variables
@@ -350,7 +357,7 b' class ui:'
         u._new_source()  # anything after that is a different level
         return u
 
-    def _maybetweakdefaults(self):
+    def _maybetweakdefaults(self) -> None:
         if not self.configbool(b'ui', b'tweakdefaults'):
             return
         if self._tweaked or self.plain(b'tweakdefaults'):
@@ -370,17 +377,17 b' class ui:'
                 if not self.hasconfig(section, name):
                     self.setconfig(section, name, value, b"<tweakdefaults>")
 
-    def copy(self):
+    def copy(self: _Tui) -> _Tui:
         return self.__class__(self)
 
-    def resetstate(self):
+    def resetstate(self) -> None:
         """Clear internal state that shouldn't persist across commands"""
         if self._progbar:
             self._progbar.resetstate()  # reset last-print time of progress bar
         self.httppasswordmgrdb = httppasswordmgrdbproxy()
 
     @contextlib.contextmanager
-    def timeblockedsection(self, key):
+    def timeblockedsection(self, key: bytes):
         # this is open-coded below - search for timeblockedsection to find them
         starttime = util.timer()
         try:
@@ -425,10 +432,10 b' class ui:'
             finally:
                 self._uninterruptible = False
 
-    def formatter(self, topic, opts):
+    def formatter(self, topic: bytes, opts):
         return formatter.formatter(self, self, topic, opts)
 
-    def _trusted(self, fp, f):
+    def _trusted(self, fp, f: bytes) -> bool:
         st = util.fstat(fp)
         if util.isowner(st):
             return True
@@ -454,7 +461,7 b' class ui:'
 
     def read_resource_config(
         self, name, root=None, trust=False, sections=None, remap=None
-    ):
+    ) -> None:
         try:
             fp = resourceutil.open_resource(name[0], name[1])
         except IOError:
@@ -468,7 +475,7 b' class ui:'
 
     def readconfig(
         self, filename, root=None, trust=False, sections=None, remap=None
-    ):
+    ) -> None:
         try:
             fp = open(filename, 'rb')
         except IOError:
@@ -480,7 +487,7 b' class ui:'
 
     def _readconfig(
         self, filename, fp, root=None, trust=False, sections=None, remap=None
-    ):
+    ) -> None:
         with fp:
             cfg = config.config()
             trusted = sections or trust or self._trusted(fp, filename)
@@ -496,7 +503,9 b' class ui:'
 
         self._applyconfig(cfg, trusted, root)
 
-    def applyconfig(self, configitems, source=b"", root=None):
+    def applyconfig(
+        self, configitems: _ConfigItems, source=b"", root=None
+    ) -> None:
         """Add configitems from a non-file source.  Unlike with ``setconfig()``,
         they can be overridden by subsequent config file reads.  The items are
         in the same format as ``configoverride()``, namely a dict of the
@@ -512,7 +521,7 b' class ui:'
 
         self._applyconfig(cfg, True, root)
 
-    def _applyconfig(self, cfg, trusted, root):
+    def _applyconfig(self, cfg, trusted, root) -> None:
         if self.plain():
             for k in (
                 b'debug',
@@ -555,7 +564,7 b' class ui:'
             root = os.path.expanduser(b'~')
         self.fixconfig(root=root)
 
-    def fixconfig(self, root=None, section=None):
+    def fixconfig(self, root=None, section=None) -> None:
         if section in (None, b'paths'):
             # expand vars and ~
             # translate paths relative to root (or home) into absolute paths
@@ -618,12 +627,12 b' class ui:'
             self._ucfg.backup(section, item),
         )
 
-    def restoreconfig(self, data):
+    def restoreconfig(self, data) -> None:
         self._ocfg.restore(data[0])
         self._tcfg.restore(data[1])
         self._ucfg.restore(data[2])
 
-    def setconfig(self, section, name, value, source=b''):
+    def setconfig(self, section, name, value, source=b'') -> None:
         for cfg in (self._ocfg, self._tcfg, self._ucfg):
             cfg.set(section, name, value, source)
         self.fixconfig(section=section)
@@ -1009,7 +1018,7 b' class ui:'
             for name, value in self.configitems(section, untrusted):
                 yield section, name, value
 
-    def plain(self, feature=None):
+    def plain(self, feature: Optional[bytes] = None) -> bool:
         """is plain mode active?
 
         Plain mode means that all configuration variables which affect
@@ -1083,7 +1092,7 b' class ui:'
             )
         return user
 
-    def shortuser(self, user):
+    def shortuser(self, user: bytes) -> bytes:
         """Return a short representation of a user name or email address."""
         if not self.verbose:
             user = stringutil.shortuser(user)
@@ -1161,14 +1170,18 b' class ui:'
         self._fmsgout, self._fmsgerr = _selectmsgdests(self)
 
     @contextlib.contextmanager
-    def silent(self, error=False, subproc=False, labeled=False):
+    def silent(
+        self, error: bool = False, subproc: bool = False, labeled: bool = False
+    ):
         self.pushbuffer(error=error, subproc=subproc, labeled=labeled)
         try:
             yield
         finally:
             self.popbuffer()
 
-    def pushbuffer(self, error=False, subproc=False, labeled=False):
+    def pushbuffer(
+        self, error: bool = False, subproc: bool = False, labeled: bool = False
+    ) -> None:
         """install a buffer to capture standard output of the ui object
 
         If error is True, the error output will be captured too.
@@ -1187,7 +1200,7 b' class ui:'
         self._bufferstates.append((error, subproc, labeled))
         self._bufferapplylabels = labeled
 
-    def popbuffer(self):
+    def popbuffer(self) -> bytes:
         '''pop the last buffer and return the buffered output'''
         self._bufferstates.pop()
         if self._bufferstates:
@@ -1197,20 +1210,20 b' class ui:'
 
         return b"".join(self._buffers.pop())
 
-    def _isbuffered(self, dest):
+    def _isbuffered(self, dest) -> bool:
         if dest is self._fout:
             return bool(self._buffers)
         if dest is self._ferr:
             return bool(self._bufferstates and self._bufferstates[-1][0])
         return False
 
-    def canwritewithoutlabels(self):
+    def canwritewithoutlabels(self) -> bool:
         '''check if write skips the label'''
         if self._buffers and not self._bufferapplylabels:
             return True
         return self._colormode is None
 
-    def canbatchlabeledwrites(self):
+    def canbatchlabeledwrites(self) -> bool:
         '''check if write calls with labels are batchable'''
         # Windows color printing is special, see ``write``.
         return self._colormode != b'win32'
@@ -1369,7 +1382,7 b' class ui:'
                 util.timer() - starttime
             ) * 1000
 
-    def _isatty(self, fh):
+    def _isatty(self, fh) -> bool:
         if self.configbool(b'ui', b'nontty'):
             return False
         return procutil.isatty(fh)
@@ -1407,10 +1420,10 b' class ui:'
         finally:
             self.restorefinout(fin, fout)
 
-    def disablepager(self):
+    def disablepager(self) -> None:
         self._disablepager = True
 
-    def pager(self, command):
+    def pager(self, command: bytes) -> None:
         """Start a pager for subsequent command output.
 
         Commands which produce a long stream of output should call
@@ -1491,7 +1504,7 b' class ui:'
             # warning about a missing pager command.
             self.disablepager()
 
-    def _runpager(self, command, env=None):
+    def _runpager(self, command: bytes, env=None) -> bool:
         """Actually start the pager and set up file descriptors.
 
         This is separate in part so that extensions (like chg) can
@@ -1571,7 +1584,7 b' class ui:'
         self._exithandlers.append((func, args, kwargs))
         return func
 
-    def interface(self, feature):
+    def interface(self, feature: bytes) -> bytes:
         """what interface to use for interactive console features?
 
         The interface is controlled by the value of `ui.interface` but also by
@@ -1626,12 +1639,12 b' class ui:'
         defaultinterface = b"text"
         i = self.config(b"ui", b"interface")
         if i in alldefaults:
-            defaultinterface = i
+            defaultinterface = cast(bytes, i)  # cast to help pytype
 
-        choseninterface = defaultinterface
+        choseninterface: bytes = defaultinterface
         f = self.config(b"ui", b"interface.%s" % feature)
         if f in availableinterfaces:
-            choseninterface = f
+            choseninterface = cast(bytes, f)  # cast to help pytype
 
         if i is not None and defaultinterface != i:
             if f is not None:
@@ -1671,7 +1684,7 b' class ui:'
 
         return i
 
-    def termwidth(self):
+    def termwidth(self) -> int:
         """how wide is the terminal in columns?"""
         if b'COLUMNS' in encoding.environ:
             try:
@@ -1918,14 +1931,14 b' class ui:'
 
     def edit(
         self,
-        text,
-        user,
-        extra=None,
+        text: bytes,
+        user: bytes,
+        extra: Optional[Dict[bytes, Any]] = None,  # TODO: value type of bytes?
         editform=None,
         pending=None,
-        repopath=None,
-        action=None,
-    ):
+        repopath: Optional[bytes] = None,
+        action: Optional[bytes] = None,
+    ) -> bytes:
         if action is None:
             self.develwarn(
                 b'action is None but will soon be a required '
@@ -1994,13 +2007,13 b' class ui:'
 
     def system(
         self,
-        cmd,
+        cmd: bytes,
         environ=None,
-        cwd=None,
-        onerr=None,
-        errprefix=None,
-        blockedtag=None,
-    ):
+        cwd: Optional[bytes] = None,
+        onerr: Optional[Callable[[bytes], Exception]] = None,
+        errprefix: Optional[bytes] = None,
+        blockedtag: Optional[bytes] = None,
+    ) -> int:
         """execute shell command with appropriate output stream. command
         output will be redirected if fout is not stdout.
 
@@ -2027,12 +2040,12 b' class ui:'
             raise onerr(errmsg)
         return rc
 
-    def _runsystem(self, cmd, environ, cwd, out):
+    def _runsystem(self, cmd: bytes, environ, cwd: Optional[bytes], out) -> int:
         """actually execute the given shell command (can be overridden by
         extensions like chg)"""
         return procutil.system(cmd, environ=environ, cwd=cwd, out=out)
 
-    def traceback(self, exc=None, force=False):
+    def traceback(self, exc=None, force: bool = False):
         """print exception traceback if traceback printing enabled or forced.
         only to call in exception handler. returns true if traceback
         printed."""
@@ -2130,7 +2143,7 b' class ui:'
         """Returns a logger of the given name; or None if not registered"""
         return self._loggers.get(name)
 
-    def setlogger(self, name, logger):
+    def setlogger(self, name, logger) -> None:
         """Install logger which can be identified later by the given name
 
         More than one loggers can be registered. Use extension or module
@@ -2138,7 +2151,7 b' class ui:'
         """
         self._loggers[name] = logger
 
-    def log(self, event, msgfmt, *msgargs, **opts):
+    def log(self, event, msgfmt, *msgargs, **opts) -> None:
         """hook for logging facility extensions
 
         event should be a readily-identifiable subsystem, which will
@@ -2239,7 +2252,7 b' class ui:'
         return self._exportableenviron
 
     @contextlib.contextmanager
-    def configoverride(self, overrides, source=b""):
+    def configoverride(self, overrides: _ConfigItems, source: bytes = b""):
         """Context manager for temporary config overrides
         `overrides` must be a dict of the following structure:
         {(section, name) : value}"""
@@ -2257,7 +2270,7 b' class ui:'
             if (b'ui', b'quiet') in overrides:
                 self.fixconfig(section=b'ui')
 
-    def estimatememory(self):
+    def estimatememory(self) -> Optional[int]:
         """Provide an estimate for the available system memory in Bytes.
 
         This can be overriden via ui.available-memory. It returns None, if
@@ -2292,7 +2305,7 b' def haveprogbar() -> bool:'
     return _progresssingleton is not None
 
 
-def _selectmsgdests(ui):
+def _selectmsgdests(ui: ui):
     name = ui.config(b'ui', b'message-output')
     if name == b'channel':
         if ui.fmsg: