Error thrown when inserting table within selection composed of multiple heading styles

[wf-gijs]

Steps to reproduce

I was able to reproduce this issue on the official examples / latest version.

1. Insert text with heading style set to paragraph.
2. Select the text and apply a heading 1 style.
3. While the selection is still active, insert a new table.
4. Deselect.
5. Make a new selection starting at the heading 1 text and include the inserted table.
6. When the table gets selected, the active heading style denoted on the toolbar dropdown button will switch to paragraph style.
7. Insert a new table while the selection is still active.
8. Editor crashes with an uncaught TypeError.

Backtrace

Uncaught TypeError: Cannot read property 'model' of null
    at LiveRange.bindWithDocument (liverange.js:121)
    at new LiveRange (liverange.js:31)
    at Function.fromRange (liverange.js:59)
    at LiveSelection._prepareRange (documentselection.js:815)
    at LiveSelection._pushRange (documentselection.js:787)
    at LiveSelection._setRanges (selection.js:469)
    at LiveSelection.setTo (selection.js:379)
    at LiveSelection.setTo (documentselection.js:719)
    at DocumentSelection._setTo (documentselection.js:418)
    at Writer.setSelection (writer.js:1155)
bindWithDocument     @ liverange.js:121
LiveRange            @ liverange.js:31
fromRange            @ liverange.js:59
_prepareRange        @ documentselection.js:815
_pushRange           @ documentselection.js:787
_setRanges           @ selection.js:469
setTo                @ selection.js:379
setTo                @ documentselection.js:719
_setTo               @ documentselection.js:418
setSelection         @ writer.js:1155
(anonymous)          @ inserttablecommand.js:63
_runPendingChanges   @ model.js:737
change               @ model.js:160
execute              @ inserttablecommand.js:58
(anonymous)          @ observablemixin.js:254
fire                 @ emittermixin.js:207
(anonymous function) @ observablemixin.js:258
execute              @ commandcollection.js:68
execute              @ editor.js:268
(anonymous)          @ tableui.js:59
fire                 @ emittermixin.js:207
fireDelegatedEvents  @ emittermixin.js:617
fire                 @ emittermixin.js:230
(anonymous)          @ inserttableview.js:97
callback             @ template.js:950
fire                 @ emittermixin.js:207
domListener          @ emittermixin.js:235

[Mgsy]

Hello, I'm not able to reproduce the issue. Can you record a screencast to show exact steps to reproduce? Also, please check if you're able to reproduce it here.

[wf-gijs]

Hello,

I recorded a screencast showing the steps taken to reproduce this issue via the Classic Editor example:

[Mgsy]

Thanks, @wf-gijs, now I'm able to reproduce the issue. However, the scenario could be simplified, you just need to insert the table at the beginning of the document, select the second block and the table, then insert a new table.

It throws with the following error:

liverange.js:121 Uncaught TypeError: Cannot read property 'model' of null
    at r.<anonymous> (liverange.js:121)
    at new r (liverange.js:31)
    at Function.fromRange (liverange.js:59)
    at p._prepareRange (documentselection.js:817)
    at p._pushRange (documentselection.js:789)
    at p._setRanges (selection.js:475)
    at p.setTo (selection.js:379)
    at p.setTo (documentselection.js:720)
    at g._setTo (documentselection.js:418)
    at We.setSelection (writer.js:1177)

cc @jodator

[wf-gijs]

Ah, I see. Thank you for the quick response!

[jodator]

There's a potential bug in the findeOptimalPosition() method - it ends up in the table and not in the root causing table to not be inserted into the model.

[jodator]

And I have a quick fix so if the change will not cause some side-effects we will try to address this in the current iteration.