Undo/redo bugs on DrawWay

[openstreetmap-trac]

Reporter: Richard
[Submitted to the original trac issue database at 2.26am, Friday, 10th December 2010]

A couple of ways to foul it up entertainingly:

• Start drawing a way. Click 'Undo' while the elastic is available. Enjoy all the fun of drawing a way without any of the consequences!

• Start drawing a way. Press Delete or Escape to end it (which maps to Undo). Click Redo. A dupe node appears (which it shouldn't). Now click the dupe node and press delete. Select a way somewhere and shift-click to add a new node. The result is a Flash exception in hitTest (WayUI line 545) which is the usual tell-tale sign of a mismatch between Ways and WayUIs.

[openstreetmap-trac]

Author: stevage
[Added to the original trac issue at 4.36am, Friday, 24th December 2010]

I had a bit of a look. It's not entirely obvious what the correct behaviour is when pressing "undo" in the middle of a draw sequence. A few possibilities:

1. Undo should be like delete/minus, except creating "redo" actions rather than "undo" ones.
2. Undo should be exactly like delete/minus (ok, that would be weird)
3. Undo should instantly remove the whole drawn way.
4. Nothing - disable. (Not as bizarre as it sounds, various other editing programs work this way.)

There's also two choices about how the whole undo/redo thing works for drawn nodes:

1. Individual nodes can be undone/redone
2. The whole sequence (between starting drawing and pressing enter/finishing) is one undo step.

[openstreetmap-trac]

Author: stevage
[Added to the original trac issue at 2.28pm, Saturday, 3rd March 2012]

Not sure if I fixed the first one in my fix for #3860, but in any case, I can't reproduce it now. (Yay). The second gives me a different error, slightly earlier in the sequence.