Problem with auto-mode-alist and x509-mode or x509-dwim

[pierre-rouleau]

Hi,

Thanks for this code, it's really useful!

I am trying to associate the various file extensions (such as .crt) with x509-mode (or x509-dwim) such that when I open the .crt file the decoding is done right away and the appropriate rendering is shown in the buffer.

I used

(add-to-list 'auto-mode-alist '("\\.crt\\'" . x509-dwim))

And that seems to work fine. However I noticed a couple of problems:

1. If the .crt file is inside a .zip file which open in archive-mode, the x509-dwim function is called, the rendering is done and then the buffer reverts back to Fundamental-mode.
2. After opening a .crt file once, and then killing the buffer, if I open the same file again it now opens in Fundamental-mode.

Overall it feels as if there was an extra call to x509-mode which takes the buffer back to Fundamental-mode.

Should this be working as one would expect, or is the design of the code precluding the use of auto-mode-alist association?

[jobbflykt]

auto-mode-alist is intended to apply a mode in the buffer itself. In the case of opening a .crt-file and running x509-dwim, what happens is that the original .crt-file remains open. When the x509 buffer is closed, the original file remains open in a (buried) buffer. When opening the same file again, that buffer is simply switched to and auto-mode-alist does not come into play. The problem is that x509-dwim is not a mode itself applied to the opened file and therefor it doesn't quite work with auto-mode-alist. Unfortunately I don't know how to make this better but it might help you to know what's going on.

When opening a file from an archive the behavior is even stranger. It seems the buffer with the archive file is switched to after x509-dwim is run. You can see this by manually switching to the corresponding x509 buffer, typically named something beginning with "*x-". This is probably caused by how archive files are opened. To help the situation somewhat, the generated x509 buffer can be automatically switched to in the archive-extract-hook.

(add-to-list 'auto-mode-alist '("\\.crt\\'" . x509-dwim))

(defun my-archive-extract-hook()
  "Switch to a x509 buffer with same basename as the current buffer."
  (if-let* ((x-buffer (get-buffer (format "*x-%s*" (buffer-name)))))
      (switch-to-buffer x-buffer)))
(add-to-list 'archive-extract-hook 'my-archive-extract-hook)

[pierre-rouleau]

Thank you for the explanation! I'll look into it later after first learning more about the archive-mode and reading your code so I can understand better.