Problem with the topology edition since version 3.40

[ludoj41-debug]

What is the bug or the crash?

Hello,

I encounter a problem with the topology edition since version 3.40.
I have 3 layers: a layer of points (gaze) attached to the top of the polylines of a line layer (channeling) and finally a layer of points (information) which are approximately 40cm from the points of the gaze layer. When I activate topological editing and want to move a point of the gaze layer, my channelization follows what is normal but the points of the information layer that are affected by the gaze I move, this moves too, but the number of points taken into account changes depending on the zoom.

I didn’t have this problem on version 3.34.

Is it a bug or an option to be disabled?

Best regards
Ludovic

Steps to reproduce the issue

activate topological editing

Versions

Version de QGIS	3.40.11-Bratislava
Révision du code	df059ed19c
Bibliothèques
Version de Qt	5.15.13
Version de Python	3.12.11
GDAL version	3.11.3 — Eganville
Version de Proj	9.6.2
Version de la base de données du registre EPSG	v12.013 (2025-05-26)
Version de GEOS	3.13.1-CAPI-1.19.2
Version de SQLite	3.50.4
Version de PDAL	2.9.0
Version du client PostgreSQL	unknown
Version de SpatiaLite	5.1.0
Version de QWT	6.3.0
Version de QScintilla2	2.14.1
Version de l'OS	Windows 11 Version 2009
Extensions Python actives
autoSaver	2.9
bd_topo_extractor	1.2.2
DigitizingTools	1.5.3
filterbyselection	0.2.6
french_locator_filter	1.1.1
gban	1.1
ImportPhotos	3.0.7
multiple_layers_tools	1.2
numericalDigitize	0.4.8
polystrip	3.0.1
profiletool	4.2.6
qchainage	3.0.1
QGISSortAndNumber-master	1.0
qsphere	6.2.2
quick_map_services	0.21.3
rwimo	0.1
Save-DXF	0.1
SgmExpressionFunctions	3.0.5
shapefile_encoding_fixer	0.7.1
shapetools	3.5.1
StreetView	3.3
VoGisProfilTool	3.0.2
volume_calculation_tool	0.4
processing	2.12.99

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response

[nicogodet]

Please illustrate, provide sample data and detailled steps to reproduce.
Just to be sure, retry with a new QGIS user profile.

[github-actions]

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[ludoj41-debug]

Hello,
You can download videos that explain problem here : [(https://www.grosfichiers.com/Vxng7Wt2pmb)]

Retry with a new QGIS user profile do not resolved the problem.

[nicogodet]

OK!
A screen cast as I can reproduce

Video.mp4

[nicogodet]

gentle ping @uclaros as you recently work on digitizing involving snap and topological editing

[uclaros]

-  loc->nearestVertex( mapPoint, 0, &myfilter, true );
-  return myfilter.matches;
+  double tol = QgsTolerance::vertexSearchRadius( canvas()->mapSettings() );
+  return loc->verticesInRect( mapPoint, tol, &myfilter, true );

@Djedouas @lbartoletti This was broken in #58352 and not caught in review.

[Djedouas]

The behavior described in this issue is the correct (and fixed) behavior.

As mentioned in the documentation the tolerance to find the vertices when clicked on the map is the "Search radius for vertex edits" setting.

This documentation section also details the difference between the snapping tolerance and the search radius.

Maybe we could add another clarification in the topological editing section stating that the detection of nearby vertices uses the "Search radius for vertex edits" setting.

@ludoj41-debug could you confirm that you get the correct behavior with this setting, please? You will need to select a value of 0.1 and "map units" according to your screencast.

Thanks.

[uclaros]

The behavior described in this issue is the correct (and fixed) behavior.

As mentioned in the documentation the tolerance to find the vertices when clicked on the map is the "Search radius for vertex edits" setting.

This documentation section also details the difference between the snapping tolerance and the search radius.

Maybe we could add another clarification in the topological editing section stating that the detection of nearby vertices uses the "Search radius for vertex edits" setting.

Absolutely not!
This behavior was silently introduced with the aforementioned PR and it completely breaks the concept of topological editing.