bug#62630: 27.1; Emacs is unable to open some jar files

[Steinar Bang]

>>>>> Steinar Bang <sb@dod.no>:

>>>> I cannot reproduce this, neither with Emacs 27.1 nor with what will be
>>>> soon Emacs 29.1.  I wonder why this happens on your system.

>> Could it be something in my config?  I will investigate this next.

> "emacs -Q" are able to open both of these files
>  
> https://www.bang.priv.no/screenshots/Screenshot%20at%202023-04-03%2007-54-54.png

> So this is something in my config, and this bug can be closed as not a
> bug in emacs.

> I will track down the offending config and report back both on this bug
> and the thread on emacs help.

The offending config was the following in my ~/.emacs:

;; editorconfig formatting support
;;;================================
(when (locate-library "editorconfig")
  (editorconfig-mode 1))

editorconfig is a minor mode that makes emacs respect formatting
settings found in .editorconfig files at the top of projects, making
emacs respect the same formatting settings as e.g. IntelliJ IDEA and
Eclipse.
 https://github.com/editorconfig/editorconfig-emacs

And all of the projects that contains .jar files that have failed to
open correctly have .editorconfig files on the top.

Removing the .editorconfig file on the top of the project with the
failing jar files removed the problem.

I bisected the .editorconfig file and found that the offending line was: 
https://github.com/steinarb/modelstore/blob/master/.editorconfig#L7

I.e:
charset = utf-8