win32mbcs: avoid unintentional failure at colorization Since 176ed32dc159, pycompat.bytestr() wrapped by win32mbcs returns unicode object, if an argument is not byte-str object. And this causes unexpected failure at colorization. pycompat.bytestr() is used to convert from color effect "int" value to byte-str object in color module. Wrapped pycompat.bytestr() returns unicode object for such "int" value, because it isn't byte-str. If this returned unicode object is used to colorize non-ASCII byte-str in cases below, UnicodeDecodeError is raised at an operation between them. - colorization uses "ansi" color mode, or Even though this isn't default on Windows, user might use this color mode for third party pager. - ui.write() is buffered with labeled=True Buffering causes "ansi" color mode internally, regardless of actual color mode. With "win32" color mode, extra escape sequences are omitted at writing data out. For example, with "win32" color mode, "hg status" doesn't fail for non-ASCII filenames, but "hg log" does for non-ASCII text, because the latter implies buffered formatter. There are many "color effect" value lines in color.py, and making them byte-str objects isn't suitable for fixing on stable. In addition to it, pycompat.bytestr will be used to get byte-str object from any types other than int, too. To resolve this issue, this patch does: - replace pycompat.bytestr in checkwinfilename() with newly added hook point util._filenamebytestr, and - make win32mbcs reverse-wrap util._filenamebytestr (this is a replacement of 176ed32dc159) This patch does two things above at same time, because separately applying the former change adds broken revision (from point of view of win32mbcs) to stable branch. "_" prefix is added to "filenamebytestr", because it is win32mbcs specific hook point.