diff mercurial/archival.py @ 49803:55d45d0de4e7

typing: add type hints to pycompat.bytestr

The problem with leaving pytype to its own devices here was that for functions
that returned a bytestr, pytype inferred `Union[bytes, int]`.  It now accepts
that it can be treated as plain bytes.

I wasn't able to figure out the arg type for `__getitem__`- `SupportsIndex`
(which PyCharm indicated is how the superclass function is typed) got flagged:

    File "/mnt/c/Users/Matt/hg/mercurial/pycompat.py", line 236, in __getitem__:
        unsupported operand type(s) for item retrieval: bytestr and SupportsIndex [unsupported-operands]
      Function __getitem__ on bytestr expects int

But some caller got flagged when I marked it as `int`.

There's some minor spillover problems elsewhere- pytype doesn't seem to
recognize that `bytes.startswith()` can optionally take a 3rd and 4th arg, so
those few places have the warning disabled.  It also flags where the tar API is
being abused, but that would be a tricky refactor (and would require typing
extensions until py3.7 is dropped), so disable those too.

--- a/mercurial/archival.py	Wed Dec 14 01:38:52 2022 -0500
+++ b/mercurial/archival.py	Wed Dec 14 01:51:33 2022 -0500
@@ -154,9 +154,14 @@
                 )
                 self.fileobj = gzfileobj
                 return (
+                    # taropen() wants Literal['a', 'r', 'w', 'x'] for the mode,
+                    # but Literal[] is only available in 3.8+ without the
+                    # typing_extensions backport.
+                    # pytype: disable=wrong-arg-types
                     tarfile.TarFile.taropen(  # pytype: disable=attribute-error
                         name, pycompat.sysstr(mode), gzfileobj
                     )
+                    # pytype: enable=wrong-arg-types
                 )
             else:
                 try: