when changing presets, delete keys from the old preset which are not in the new preset

CHANGELOG.md

@@ -67,7 +67,7 @@
 # v2.37.2
 ##### 2025-10-30
 
 * Correctly resolve subtitles of NSI presets when base preset has a crossreferenced string ([#11527])
 
 [#11527]: https://github.com/openstreetmap/iD/issues/11527
 
@@ -307,6 +307,7 @@
 #### :mortar_board: Walkthrough / Help
 * Change background imagery of walkthrough tutorial to Bing (the previous source is not available anymore)
 #### :rocket: Presets
+* When changing presets, delete tags from the old preset which are not in the new preset ([#11696], thanks [@k-yle])
 * Suggest housenumber/housename values from surrounding areas ([#10946])
 #### :hammer: Development
 * Drop support for Node 18
@@ -324,6 +325,7 @@
 [#10997]: https://github.com/openstreetmap/iD/issues/10997
 [#11006]: https://github.com/openstreetmap/iD/issues/11006
 [#11011]: https://github.com/openstreetmap/iD/issues/11011
+[#11696]: https://github.com/openstreetmap/iD/pull/11696
 [@ChaitanyaKadu03]: https://github.com/ChaitanyaKadu03
 
 

modules/actions/change_preset.js

@@ -1,3 +1,5 @@
+import { utilArrayDifference, utilObjectOmit } from '../util';
+
 export function actionChangePreset(entityID, oldPreset, newPreset, skipFieldDefaults) {
     return function action(graph) {
         var entity = graph.entity(entityID);
@@ -18,9 +20,22 @@ export function actionChangePreset(entityID, oldPreset, newPreset, skipFieldDefa
                 // https://github.com/openstreetmap/iD/issues/9372
                 newPreset.fields(loc).concat(newPreset.moreFields(loc))
                     .filter(f => f.matchGeometry(geometry))
-                    .map(f => f.key).filter(Boolean)
+                    .flatMap(f => f.allKeys())
+                    .filter(Boolean)
                     .forEach(key => preserveKeys.push(key));
             }
+
+            if (oldPreset) {
+                // 'field-keys' are keys used by fields (different to the keys used by preset itself)
+                const oldPresetFieldKeys = [
+                    ...oldPreset.fields(loc),
+                    ...oldPreset.moreFields(loc)
+                ].flatMap(f => f.allKeys());
+
+                // field-keys used by the old preset but not the new preset
+                const fieldKeysToRemove = utilArrayDifference(oldPresetFieldKeys, preserveKeys);
+                tags = utilObjectOmit(tags, fieldKeysToRemove);
+            }
         }
         if (oldPreset) tags = oldPreset.unsetTags(tags, geometry, preserveKeys, false, loc);
         if (newPreset) tags = newPreset.setTags(tags, geometry, skipFieldDefaults, loc);

modules/presets/field.js

@@ -53,5 +53,13 @@ export function presetField(fieldID, field, allFields) {
 
   _this.increment = (_this.type === 'number' || _this.type === 'integer') ? (_this.increment || 1) : undefined;
 
+  /** all keys controlled by this field */
+  _this.allKeys = () => {
+    const allKeys = [];
+    if (_this.key) allKeys.push(_this.key);
+    if (_this.keys) allKeys.push(..._this.keys);
+    return allKeys;
+  };
+
   return _this;
 }

test/spec/actions/change_preset.js

@@ -84,6 +84,47 @@ describe('iD.actionChangePreset', function() {
         expect(action(graph).entity(entity.id).tags).to.eql({amenity: 'school'});
     });
 
+    it('does not preserve field tags which only exist in the old preset, not in the new preset', () => {
+        const entity = iD.osmNode({
+            tags: {
+                building: 'yes', // case 1: the preset's own tags.
+                'roof:colour': 'pink', // case 2: a field which exists in the old preset, but not the new one.
+                check_date: '2025-12-05', // case 3: a field which exists in the old AND new preset.
+                grades: '0-13', // case 4: a field which exists only in the new preset, not in the old one.
+                'ref:SG:address_id': '1234', // case 5: a tag which does not exist in either preset
+            },
+            loc: [0, 0],
+        });
+        const graph = iD.coreGraph([entity]);
+
+        const fields = {
+            'roof:colour': iD.presetField('roof:colour', { key: 'roof:colour', geometry: 'point' }),
+            check_date: iD.presetField('check_date', { key: 'check_date', geometry: 'point' }),
+            grades: iD.presetField('roof:colour', { key: 'grades', geometry: 'point' }),
+        };
+
+        const oldPreset = iD.presetPreset(
+            'building/yes',
+            { tags: { building: 'yes' }, fields: ['roof:colour', 'check_date'] },
+            undefined,
+            fields,
+        );
+        const newPreset = iD.presetPreset(
+            'amenity/school',
+            { tags: { amenity: 'school' }, fields: ['check_date', 'grades'] },
+            undefined,
+            fields,
+        );
+        const action = iD.actionChangePreset(entity.id, oldPreset, newPreset);
+        expect(action(graph).entity(entity.id).tags).toStrictEqual({
+            amenity: 'school', // case 1: the preset's own tags were replaced.
+            // case 2: the field which exists in the old preset was removed (roof:colour).
+            check_date: '2025-12-05', // case 3: the field which exists in the old AND new preset was kept.
+            grades: '0-13', // case 4: a field which exists only in the new preset was also kept.
+            'ref:SG:address_id': '1234', // case 5: tags which do not exist in either preset are kept
+        });
+    });
+
     // https://github.com/openstreetmap/iD/issues/9372
     it('does not preserve field tags when changing from a subpreset to its parent', function() {
         var entity = iD.osmNode({tags: {highway: 'service', service: 'driveway'}});