bug#62815: Gnus: MIME types of attachments contain regexp quotation

[Arash Esbati <arash@gnu.org>]

Andrew Cohen <cohen@bu.edu> writes:

> If all this is right, the simple fix is to revert the part of
> 3faa508eba84a1983732099cbd3cc1eaad404158 that treated the extension data
> as regexps.  I have attached a diff below that does this. If Torsten
> and Arash can check if this continues to provide a fix for bug#52038 and
> bug#62815 that would be great!

Thanks for looking at this.  I built the latest repo version
(65735cee71) of Emacs and tried it with and w/o your patch.  It seems to
fix the issues Torsten and I have reported, but ...

> There is one more place I think needs fixing (and maybe others I haven't
> spotted yet):

I see a strange side effect when I use 'e' in article buffer to view a
attachment.  Without your change, Emacs starts Excel like this (this it
at least I see in *Messages* buffer) and it works:

  Displaying start excel.exe "`cygpath -w -a c\:/msys64/tmp/emm.fMzcnA/file_name.xlsx`"

With your change, I get:

  Displaying start excel.exe "`cygpath -w -a "c:/msys64/tmp/emm.QDUAFP/file_name.xlsx"`"

which doesn't work due to extra pair of quotes.  This is the entry in my
.mailcap:

  application/vnd.openxmlformats-officedocument.spreadsheetml.sheet; \
                       start excel.exe "`cygpath -w -a %s`"

This on Win10.

Best, Arash