typing: add type hints to the `charencode` module Since this module is dynamically imported from either `mercurial.pure` or `mercurial.cext`, these hints aren't detected in `mercurial.encoding`, and need to be imported directly there during the type-checking phase. This keeps the runtime selection via the policy config in place, but allows pytype to see these as functions with proper signatures instead of just `Any`. We don't attempt to import the `mercurial.cext` version yet because there's no types stubs for that module, but this will get the ball rolling. I thought this would spill over into other modules from there, but the only two *.pyi files that changed were for `encoding` and `charencode`. Applying this to other dynamically selected modules will clean some things up in other files, so this is a start. I had originally redefined the functions in the type-checking block (like some of the `os.path` aliasing in `mercurial.util`), but this is better because we won't have another duplication of the definitions that may get out of date.

--- a/mercurial/encoding.py	Fri Jul 19 16:49:46 2024 -0400
+++ b/mercurial/encoding.py	Fri Jul 19 20:09:48 2024 -0400
@@ -40,6 +40,16 @@
 
 unichr = chr
 
+if typing.TYPE_CHECKING:
+    # TODO: make a stub file for .cext.charencode, and import here
+    from .pure.charencode import (
+        asciilower,
+        asciiupper,
+        isasciistr,
+        jsonescapeu8fast as _jsonescapeu8fast,
+    )
+
+
 # These unicode characters are ignored by HFS+ (Apple Technote 1150,
 # "Unicode Subtleties"), so we need to ignore them in some places for
 # sanity.
@@ -524,7 +534,7 @@
     other = 0
 
 
-def jsonescape(s: Any, paranoid: Any = False) -> Any:
+def jsonescape(s: bytes, paranoid: bool = False) -> bytes:
     """returns a string suitable for JSON
 
     JSON is problematic for us because it doesn't support non-Unicode