Cursor kicking makes `M-x delete-trailing-whitespace` delete newline at the end of each form feed

Question

Cursor kicking makes `M-x delete-trailing-whitespace` delete newline at the end of each form feed

wasamasa opened this issue 9 years ago · comments

Vasilij Schneidermann commented 9 years ago

M-x delete-trailing-whitespace contains a hack to counter Emacs assumption of a form feed being whitespace (yes, seriously). The cursor kicking feature messes this hack up and makes the command delete a newline at the end of the displayed line which is not ok.

I can think of two ways of going at this. The fun way would involve writing a more powerful variant of called-interactively-p to detect whether the point-entered function was called by an interactive movement command. The boring way would involve submitting a bug report for Emacs, providing a minimal example and explaining the actual problem in excruciating detail, hoping that someone will take a look at it and provide a fix.

Vasilij Schneidermann · Answer 1 · Fri May 15 2015 06:51:59 GMT+0800 (China Standard Time)

Considering that Stefan is on a crusade to eradicate similiar behaviour and the fact that cursor kicking was added to avoid the visual glitch of point on such a line hiding it in graphical Emacs instances (textual ones don't expose this), I think I'll just remove the feature after handing in a bug report about that oddity.

Lars Andersen · Answer 2 · Wed Sep 16 2015 15:51:06 GMT+0800 (China Standard Time)

Bump

I noticed such a blank line disappearing in one of my diffs just now. I didn't call delete-trailing-whitespace, nor did ethan-wspace-mode do this in its after-save-hook, but toggling this mode prevents it from happening.

Vasilij Schneidermann · Answer 3 · Thu Sep 17 2015 01:05:58 GMT+0800 (China Standard Time)

@expez You can temporarily work around this by customizing form-feed-kick-cursor before enabling form-feed-mode. See #2 for earlier discussion of this problem.

I'm writing a minimal example for reproducing the display bug and will submit a bug report afterwards, then I can dike the feature out and live with that glitch until its fixed in the Git release :)

Vasilij Schneidermann · Answer 4 · Thu Sep 17 2015 03:55:36 GMT+0800 (China Standard Time)

http://debbugs.gnu.org/cgi/bugreport.cgi?bug=21500

I don't ever expect it to get fixed, but I can deal with it.

Lars Andersen · Answer 5 · Thu Sep 17 2015 04:06:30 GMT+0800 (China Standard Time)

Great!

I did (setq form-feed-kick-cursor nil), prior to starting the mode, and will keep watching this thread :)

Vasilij Schneidermann · Answer 6 · Thu Sep 17 2015 04:18:38 GMT+0800 (China Standard Time)

Thanks for reminding me about this.

Vasilij Schneidermann · Answer 7 · Sat Sep 26 2015 20:58:38 GMT+0800 (China Standard Time)

I've got a workaround for the cursor thing, see http://debbugs.gnu.org/cgi/bugreport.cgi?bug=21500#35 for further details. This means that you'll need to customize the face in your theme, but eh, I can live with that.