Language pragma snippet corrupts undo history

[brandonw]

If you do the initial expand of the lang snippet into {-# LANGUAGE #-} but then cancel the expansion before choosing the extension, your undo history will not contain the insertion of {-# LANGUAGE #-}.

It looks as if the text outputted from the snippet before the macro is invoked is somehow not added to the undo history. I tried putting the entire content of the snippet inside of the macro instead of just the extension, but that somehow adds a line break that is not added to the undo history instead.

[chrisdone]

This is yasnippet?

[brandonw]

Yes, it was. I haven't used emacs & haskell-mode in a while, so I'm not sure if this still exists.

[gracjan]

Related #364, #305, #361.

[lukehoersten]

This is still an issue and since this is my code I'll try to figure out what's going on.

[lukehoersten]

I have no idea why this is happening. @capitaomorte can you provide any insight here?

[joaotavora]

Undo support in yasnippet is finicky, but it should work. Can I see the snippet definition? Alternatively open related issue in yasnippet.

[lukehoersten]

@capitaomorte https://github.com/haskell/haskell-snippets/blob/master/snippets/haskell-mode/lang-pragma

I'll wait to open a yasnippet issue until we've determined this isn't something I've caused.