bug#39190: 28.0.50; two buffers with same buffer-file-name (diff-syntax-fontify-props)

[Juri Linkov]

>> Now I tried to repeat this problem with eglot and got such backtrace:
> [...]
>
> Did you use the ELPA version or the git master?

The backtrace was from the ELPA version, but trying it
in the git master signals a different error:

Error in post-command-hook:
(error "[eglot] Can't guess mode to manage for ` *diff-syntax:...

> Having read your discussion I have a feeling that this issue affects
> more than just Eglot.  Nevertheless we plan a feature that postpones the
> activation of Eglot and this feature is somewhat similar to Stefan's
> first suggestion.  So if the only concern is Eglot, then this issue can
> be closed.

Since it will take much time when the fix in Emacs will appear in a released
version, a workaround needs to be added to Eglot immediately.