Let features know about undo batch

[jodator]

So I have an issue with undoing automatic text transformations. Scenario:

• user types "woot"
• feature replaces "woot" to „woot” (using a new batch)
• users decides to undo change (CTRL-Z) to "woot"
  Now the feature does not know if that "data:change" event is for undoing batch. I can listen to undo command execution and filter out those batches but it looks like we could add another type of batch?

This is rather open discussion as I only know about: default and transparent type of batches ATM.

[jodator]

So after F2F talks with @scofalik we came to a conclusion that adding a batch type "undo" makes sense:

• there's an actual need of other features to know about that change is coming from "undo" not user interaction
• another solution for this problem looks less clean (ie checking if batch is in undo stack)
• the redo should also have "undo" type - as in such scenario:
  1. user types "foo bar"
  2. text transformation changes to „foo bar”
  3. user undo (1): text becomes "foo bar" again
  4. user undo (2): part of text (depending on buffer) is removed: "foo
  5. user redo (1): the text should be "foo bar" (and no automatic transformation to be applied)
  6. user redo (2): the transformation i re-applied: „foo bar”

At the moment I see that undo type makes sense as

• features might introduce other types of batch.
• the undo batch will be present only with Undo plugin enabled
• the batch type should be documented in feature description

//cc @pjasiun

[pjasiun]

I'm fine with marking "undo" and "redo" batches as "undo" with a special flag.

[jodator]

batches as "undo" with a special flag.

@pjasiun: To be precise: batch.specialFlag = true or batch.type = 'undo' - the latter (batch.type=undo) was proposed here.

[pjasiun]

After F2F talk we agreed that we can try to mark these baches as transparent.

[jodator]

After another F2F talk with @pjasiun & @scofalik we agreed on checking first if the undo feature shouldn't use transparent batches in the first place (instead of currently default).