bug#23053: 25.0.92; error in cc-mode when editing C# file with a generic class inheritance

[Saulius Menkevičius]

Alan Mackenzie <acm@muc.de> writes:

> Hello, Saulius.
>
> On Sat, Mar 19, 2016 at 04:15:53PM +0200, Saulius Menkevičius wrote:
>
>> Hi,
>
>> Not sure why I did not receive and email directly from debbugs.gnu.org
>> (maybe there is some delay in mail transfer mechanism on the way).
>
> I answered your mail directly, with a copy to debbugs.gnu.org.  But
> things can go wrong with email.
>
>> > Thanks for such an informative bug report.  Could you possibly tell me
>> > what major mode you're using (presumably some C# Mode) and where I can
>> > get a copy of it from, please.  That will enable me to reproduce the
>> > problem.
>
>> The mode in question is csharp-mode, from MELPA:
>
>>     csharp-mode is a dependency package.
>
>>         Status: Installed in ‘csharp-mode-20160217.1211/’ (unsigned).
>>         Version: 20160217.1211
>>         Summary: C# mode derived mode
>>     Homepage: https://github.com/josteink/csharp-mode
>>     Keywords: c# languages oop mode 
>>     Other versions: 20160217.1211 (melpa-stable), 0.8.12 (marmelade).
>
> OK, I've got it, thanks.  In particular, the 0.8.12 version from MELPA.
>
> Next question: have you actually compiled it with the emacs-25 repository
> code?  What makes me think you might not have, is that there are lots of
>
>     (looking-back <string>)
>
> instances in the code, which no longer compile.  (They need to have a nil
> inserted after <string>, giving (looking-back <string> nil).)  As soon as
> I made these edits, then recompiled csharp-mode.el inside the emacs-25
> repo version, the code ran just fine.  Actually, I think I had manually
> to load cc-langs.elc to get it to compile properly; I think the following
> line is missing from near the top of csharp-mode.el:
>
>     (eval-when-compile (require 'cc-langs))
>
> Explanation for the bug I saw: a new "language variable",
> c-<>-notable-chars-re, had been defined in CC Mode, but not compiled into
> the csharp-mode part.  That left it's value at nil, rather than the
> string it should be.  This nil then caused the error.
>
> But it could be I'm looking at totally the wrong problem.

It worked for me, actually. Removing csharp-mode and then reinstalling
via package manager fixed the issue for me.

>
>> Not sure if you've checked the tracked for this issue, but Jostein
>> Kjønigsen <jostein <at> secure.kjonigsen.net> wrote:
>
>>     I've run this test-case against the "regular" Windows build 24.5.1,
>>     using latest csharp-mode package and it runs fine. Trying latest Emacs
>>     from git master on Ubuntu I can reproduce this error systematically
>>     using the exact same version of csharp-mode.
>
> Exact same source code, or exact same binary?  The source code will need
> recompiling for the emacs-25 repo.  csharp-mode.elc compiled for an earlier
> version will definitely produce this error on emacs-25.
>
>> So this is can be replicated with bare emacs-25 from git + csharp-mode from
>> MELPA. Also someone wrote that the same thing happens with Java mode too
>> where the code being edited uses generics (as C# and Java generics syntax is
>> very similar).
>
> The same thing happening on Java would surprise me.  That would imply a
> different problem.

I couldn't replicate the Java issue myself..

>
> So, to sum up: please make sure the compiled version of csharp-mode
> you're using has been compiled on the Emacs you're using it on.  Thanks!
>
>> > > In GNU Emacs 25.0.92.3 (x86_64-apple-darwin15.3.0, NS appkit-1404.34 
>> > > Version 10.11.3 (Build 15D21))
>> > >  of 2016-03-17 built on mbp.local
>> > > Repository revision: 9ab03f27fad7b1ae68dda7a2effd075658dcf184
>> > > Windowing system distributor 'Apple', version 10.3.1404
>> > > Configured using:
>> > >  'configure --with-gnutls --with-ns'
>
>> > > Configured features:
>> > > JPEG DBUS NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS NS
>
>> > > Important settings:
>> > >   value of $LANG: de_LT
>> > >   locale-coding-system: utf-8
>
>> > > Major mode: mu4e-headers
>
>> > ???
>
>> Oh, it was my first time using `report-emacs-bug', -- I invoked
>> it from my mail client buffer instead of from the csharp-mode that has
>> issue itself.
>
> No, by "???" I just meant "mu4e-headers is something I'm not familiar
> with.".
>
>> Thanks!
>
>> -- 
>> Saulius Menkevičius (saulius.menkevicius@gmail.com)

So the issue is resolved for me, reinstalling csharp-mode fixed it. Not
sure it works for Jostein.

-- 
Saulius Menkevičius (saulius.menkevicius@gmail.com)