"Split Features" tool does not honor topological editing

[andywicht]

Hi Bernhard,

when splitting a feature in order to merge the split off part to an adjacent feature, the necessary vertex for clean merging is not inserted into the adjacent polygon after/while splitting. The QGIS core tool does honor the topological editing settings and inserts a vertex in the adjacent feature.

Example

split one part using one existing vertex

vertex missing in adjacent polygon

desired result

Greetings