Pass display-buffer-mark-dedicated to purpose-change-buffer to fix br…

[wyuenho]

…oken kill-buffer

This PR fixes the bug where (kill-buffer nil) doesn't kill the window when you expect it to. This problem is particularly severe for undo-tree. In particular, undo-tree-visualizer-quit will call (kill-buffer nil) to kill the visualizer window on quit. Without this fix, the undo-tree visualizer window will remain even after quitting.

[coveralls]

Coverage remained the same at 67.318% when pulling 5d422f1 on wyuenho:pass-dedicated into 2655bbe on bmag:master.

[coveralls]

Coverage increased (+1.05%) to 66.869% when pulling 7f021f8 on wyuenho:pass-dedicated into 8737c5d on bmag:master.

[bmag]

Hey, thanks for your interest. This looks like a good contribution, but I want to test it out a bit before merging. Unfortunately, I have a busy schedule so I'm not sure that will happen.

[wyuenho]

If you look at window.el in your emacs installation, a lot of the display-buffer-* display buffer actions pass display-buffer-mark-dedicated on. I've already kept this PR to the 2 that I know for sure is necessary for vanilla emacs. Hopefully you'll get some time to test this PR soon.

[wyuenho]

@bmag How does this look now?

[bmag]

It looks fine. I wrote (in my local clone) some tests for this, to be safe, but they failed. It was probably a problem with the tests, not the feature, but I haven't been able to resume work on it yet.

[wyuenho]

Ah. Let me know if there's anything else I can help! I honestly don't know how to write tests for this.

[bmag]

Thanks, merged. Added tests in 15e6d44