tags 32201 + patch
quit

John Shahid <jvshahid@gmail.com> writes:
>
>     (add-hook 'buffer-list-update-hook
>               (lambda ()

>                          (setenv "GOPATH" gopath))))))

> The problem seems to happen when all of the suddent 'find-file' will
> start openning weird files.  For example, if I'm currently viewing
> "~/foo/bar.txt" and use 'C-x C-f' the default file name will be
> "~/foo/~jvshahid/foo/bar.txt".  After some debugging it turns out that
> the following will happen which cause the match-data to be corrupted:
>
> 1. find-file calls abbreviate-file-name
> 2. abbreviate-file-name calls (expand-file-name "~")
> 3. expand-file-name runs the buffer-list-update-hook (unknown why)
> 4. the hook will use setenv which messes up the match-data
> 5. abbreviate-file-name resumes and use the incorrect match-data and return an invalid path
>
> I don't know why '3' is happening.

buffer-list-update-hook gets called by get-buffer-create and
kill-buffer; it seems plausible that some file name handlers would use
make-temp-buffer which calls both of those.

Anyway, I don't think setenv should be changed, rather
abbreviate-file-name should save-match-data around the expand-file-name
call.  After all, today you happened to use setenv in a hook, tomorrow
someone will use another match-data modifying function.

Here's the patch (intended for emacs-26):