fix: prevent datalayer to resetting to an old version on save

This happens in collaborative mode only.

cf #1536
cf #1537

cf https://forum.openstreetmap.fr/t/probleme-de-sauvegarde-des-cartes/20596
cf https://forum.openstreetmap.fr/t/umap-soucis-de-debutants/20538
cf https://forum.openstreetmap.fr/t/probleme-de-maj-des-icones/20565

umap/static/umap/js/umap.layer.js

@@ -1572,6 +1572,7 @@ L.U.DataLayer = L.Evented.extend({
         if (data.geojson) {
           this.clear()
           this.fromGeoJSON(data.geojson)
+          delete data.geojson
         }
         this._geojson = geojson
         this._last_modified = response.getResponseHeader('Last-Modified')

umap/tests/integration/test_collaborative_editing.py

@@ -0,0 +1,124 @@
+from playwright.sync_api import expect
+
+from umap.models import DataLayer
+
+from ..base import DataLayerFactory, MapFactory
+
+
+def test_collaborative_editing_create_markers(context, live_server, tilelayer):
+    # Let's create a new map with an empty datalayer
+    map = MapFactory(name="collaborative editing")
+    datalayer = DataLayerFactory(map=map, edit_status=DataLayer.ANONYMOUS, data={})
+
+    # Now navigate to this map and create marker
+    page_one = context.new_page()
+    page_one.goto(f"{live_server.url}{map.get_absolute_url()}?edit")
+
+    save_p1 = page_one.get_by_role("button", name="Save")
+    expect(save_p1).to_be_visible()
+
+    # Click on the Draw a marker button on a new map.
+    create_marker_p1 = page_one.get_by_title("Draw a marker")
+    expect(create_marker_p1).to_be_visible()
+    create_marker_p1.click()
+
+    # Check no marker is present by default.
+    marker_pane_p1 = page_one.locator(".leaflet-marker-pane > div")
+    expect(marker_pane_p1).to_have_count(0)
+
+    # Click on the map, it will place a marker at the given position.
+    map_el_p1 = page_one.locator("#map")
+    map_el_p1.click(position={"x": 200, "y": 200})
+    expect(marker_pane_p1).to_have_count(1)
+
+    save_p1.click()
+    assert DataLayer.objects.get(pk=datalayer.pk).settings == {
+        "browsable": True,
+        "displayOnLoad": True,
+        "name": "test datalayer",
+    }
+
+    # Now navigate to this map from another tab
+    page_two = context.new_page()
+
+    page_two.goto(f"{live_server.url}{map.get_absolute_url()}?edit")
+
+    save_p2 = page_two.get_by_role("button", name="Save")
+    expect(save_p2).to_be_visible()
+
+    # Click on the Draw a marker button on a new map.
+    create_marker_p2 = page_two.get_by_title("Draw a marker")
+    expect(create_marker_p2).to_be_visible()
+    create_marker_p2.click()
+
+    # Check that the marker created in the orther tab is present.
+    marker_pane_p2 = page_two.locator(".leaflet-marker-pane > div")
+    expect(marker_pane_p2).to_have_count(1)
+
+    # Click on the map, it will place a marker at the given position.
+    map_el_p2 = page_two.locator("#map")
+    map_el_p2.click(position={"x": 220, "y": 220})
+    expect(marker_pane_p2).to_have_count(2)
+
+    save_p2.click()
+    # No change after the save
+    expect(marker_pane_p2).to_have_count(2)
+    assert DataLayer.objects.get(pk=datalayer.pk).settings == {
+        "browsable": True,
+        "displayOnLoad": True,
+        "name": "test datalayer",
+        "inCaption": True,
+        "editMode": "advanced",
+    }
+
+    # Now create another marker in the first tab
+    create_marker_p1.click()
+    map_el_p1.click(position={"x": 150, "y": 150})
+    expect(marker_pane_p1).to_have_count(2)
+    save_p1.click()
+    # Should now get the other marker too
+    expect(marker_pane_p1).to_have_count(3)
+    assert DataLayer.objects.get(pk=datalayer.pk).settings == {
+        "browsable": True,
+        "displayOnLoad": True,
+        "name": "test datalayer",
+        "inCaption": True,
+        "editMode": "advanced",
+        "id": datalayer.pk,
+        "permissions": {"edit_status": 1},
+    }
+
+    # And again
+    create_marker_p1.click()
+    map_el_p1.click(position={"x": 180, "y": 150})
+    expect(marker_pane_p1).to_have_count(4)
+    save_p1.click()
+    # Should now get the other marker too
+    assert DataLayer.objects.get(pk=datalayer.pk).settings == {
+        "browsable": True,
+        "displayOnLoad": True,
+        "name": "test datalayer",
+        "inCaption": True,
+        "editMode": "advanced",
+        "id": datalayer.pk,
+        "permissions": {"edit_status": 1},
+    }
+    expect(marker_pane_p1).to_have_count(4)
+
+    # And again from the second tab
+    expect(marker_pane_p2).to_have_count(2)
+    create_marker_p2.click()
+    map_el_p2.click(position={"x": 250, "y": 150})
+    expect(marker_pane_p2).to_have_count(3)
+    save_p2.click()
+    # Should now get the other markers too
+    assert DataLayer.objects.get(pk=datalayer.pk).settings == {
+        "browsable": True,
+        "displayOnLoad": True,
+        "name": "test datalayer",
+        "inCaption": True,
+        "editMode": "advanced",
+        "id": datalayer.pk,
+        "permissions": {"edit_status": 1},
+    }
+    expect(marker_pane_p2).to_have_count(5)