Remove temp files /tmp/fineDiff* for kill-emacs without quit ediff

[sunlin7]

Fix a bug that the temp files /tmp/fineDiff* were left after Spacemacs ediff templates.

Reproducing steps: Pressing SPC f e D and press n to locate first diff line, then press SPC f q to quick Spacemacs directly.

Then the /tmp/fineDiff* files left.

[bcc32]

For context, here is the upstream bug which adds the ediff function mentioned here.

[bcc32]

IMO that's a pretty trivial bug, and I don't think "upstream Emacs will make this change eventually" is a generally a good reason on its own to backport a similar patch to Spacemacs---it's not even related to Spacemacs functionality, only ediff itself. I would vote to just close this, but will wait for others to chime in.

[sunlin7]

I found the /tmp/fineDiff* files after Spacemacs SPC f e D function, and got the root cause, pushed the patch to emacs upstream.

So I hope Spacemacs user won't be bothered by using the SPC f e D function, that's why I pushed the solution here.

[bcc32]

That doesn't really address my root concern: I don't think backporting random things to Spacemacs is worth the maintenance burden, especially when the impact is so low. (I can't imagine the existence of some files in /tmp is really bothering anybody, especially since they get cleaned up if you properly exit the ediff session).

Can explain why these files not getting cleaned up is actually causing you problems?

[sunlin7]

When using Spacemacs on a never-rebooted linux server with shared /tmp/ folder, other users on the server can see the fineDiff* files were created again and again, they will find the creator and kindly reminder me with mail/chat that maybe some leak happened.

[bcc32]

Okay so that's pretty specific to your site and not exactly catastrophic. Why not just fix it in your config, or use site-start?

[sunlin7]

This issue happened on using the Spacemacs SPC f e D function, I do fixed it on my local about a month ago. And hope the solution can help the Spacemacs users who still with emacs-28/29/30.