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

py3: catch FileExistsError instead of checking errno == EEXIST

py3: catch BrokenPipeError instead of checking errno == EPIPE

py3: catch ChildProcessError instead of checking errno == ECHILD

py3: remove retry on EINTR errno Since the implementation of PEP 475 (Python 3.5), Python retries system calls failing with EINTR. Therefore we don’t need the logic that retries it in Python code.