windows: prevent bytes from being passed to registry APIs There was a TortoiseHg bug report in this area[1], and from inspection, it looks like passing `b""` as `valname` would fail to convert to unicode. The underlying API allows both `""` and `NULL` to return the default value for the key. [1] https://foss.heptapod.net/mercurial/tortoisehg/thg/-/issues/5803

relnotes: add 6.1.3

cleanup: return directly instead of assigning variable

commit: remove special handling of IOError (actually dead code) In the past, IOError was used to mark a file as removed. The differentiation between OSError and IOError in this place was introduced in e553a425751d, to avoid that “normal” OSErrors / IOErrors accidentally mark files as removed. This weird internal API was removed in 650b5b6e75ed. It seems like that changeset should have removed the differentiation, at least I don’t see any reason for keeping it. On Python 3, OSError and IOError are aliased. Therefore the removed code was actually dead.

py3: catch specific OSError subclasses instead of checking errno On Python 3, the "not a directory" error is mapped to ENOTDIR instead of EINVAL. Therefore, catching the NotADirectoryError subclass is sufficient.

py3: catch specific OSError subclasses instead of checking errno Contrary to the previous changesets in this series, this covers cases where errno was checked for multiple values. EACCES -> PermissionError ENOENT -> FileNotFoundError ENOTDIR -> NotADirectoryError EISDIR -> IsADirectoryError

py3: catch ProcessLookupError instead of checking errno == ESRCH

py3: catch PermissionError instead of checking errno == EPERM

py3: catch PermissionError instead of checking errno == EACCES

py3: catch FileNotFoundError instead of checking errno == ENOENT