On Wikidata, the VisualEditor feature to suggest previous edit summaries to me is no longer working. The console has the following error:
jQuery.Deferred exception: can't access property "match", summary is undefined
Full stack trace with debug=true:
jQuery.Deferred exception: can't access property "match", summary is undefined ve.ui.MWEditSummaryWidget.static.splitSummary@https://www.wikidata.org/w/extensions/VisualEditor/modules/ve-mw/ui/widgets/ve.ui.MWEditSummaryWidget.js?4ca0e:60:15 ve.ui.MWEditSummaryWidget.prototype.getSummaries/this.getSummariesPromise</<@https://www.wikidata.org/w/extensions/VisualEditor/modules/ve-mw/ui/widgets/ve.ui.MWEditSummaryWidget.js?4ca0e:143:14 ve.ui.MWEditSummaryWidget.prototype.getSummaries/this.getSummariesPromise<@https://www.wikidata.org/w/extensions/VisualEditor/modules/ve-mw/ui/widgets/ve.ui.MWEditSummaryWidget.js?4ca0e:142:7 mightThrow@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3557:29 resolve/</process<@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3625:12 setTimeout handler*resolve/<@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3663:16 fire@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3291:31 fireWith@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3421:7 fire@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3429:10 fire@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3291:31 fireWith@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3421:7 Deferred/</deferred[tuple[0]]@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3759:36 ajax/xhr<@https://www.wikidata.org/w/resources/src/mediawiki.api/index.js?06bae:273:19 fire@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3291:31 fireWith@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:3421:7 done@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:9533:14 callback/<@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:9785:17 EventHandlerNonNull*send@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:9804:18 ajax@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:9434:15 jQuery.ajax@https://www.wikidata.org/w/resources/lib/jquery/jquery.migrate.js?075cf:272:22 ajax@https://www.wikidata.org/w/resources/src/mediawiki.api/index.js?06bae:245:12 get@https://www.wikidata.org/w/resources/src/mediawiki.api/index.js?06bae:137:16 ve.ui.MWEditSummaryWidget.prototype.getSummaries@https://www.wikidata.org/w/extensions/VisualEditor/modules/ve-mw/ui/widgets/ve.ui.MWEditSummaryWidget.js?4ca0e:129:60 ve.ui.MWEditSummaryWidget.prototype.getLookupRequest@https://www.wikidata.org/w/extensions/VisualEditor/modules/ve-mw/ui/widgets/ve.ui.MWEditSummaryWidget.js?4ca0e:168:14 OO.ui.mixin.LookupElement.prototype.getRequest@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-widgets.js?6523e:992:14 OO.ui.mixin.RequestManager.prototype.getRequestData@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-widgets.js?6523e:533:43 OO.ui.mixin.LookupElement.prototype.getLookupMenuItems@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-widgets.js?6523e:909:14 OO.ui.mixin.LookupElement.prototype.populateLookupMenu@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-widgets.js?6523e:867:8 OO.ui.mixin.LookupElement.prototype.onLookupInputChange@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-widgets.js?6523e:765:8 OO.EventEmitter.prototype.emit@https://www.wikidata.org/w/resources/lib/oojs/oojs.jquery.js?e3185:876:12 OO.ui.InputWidget.prototype.setValue@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-core.js?f68df:9713:8 OO.ui.InputWidget.prototype.onEdit/<@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-core.js?f68df:9664:11 setTimeout handler*OO.ui.InputWidget.prototype.onEdit@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-core.js?f68df:9663:13 dispatch@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:5237:27 add/elemData.handle@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:5044:28 EventListener.handleEvent*add@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:5092:12 jQuery.event.add@https://www.wikidata.org/w/resources/lib/jquery/jquery.migrate.js?075cf:503:21 on/<@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:4992:16 each@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:367:19 each@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:202:17 on@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:4991:14 on@https://www.wikidata.org/w/resources/lib/jquery/jquery.js?11c05:5728:10 OoUiInputWidget@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-core.js?f68df:9572:14 OoUiTextInputWidget@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-core.js?f68df:11143:30 OoUiMultilineTextInputWidget@https://www.wikidata.org/w/resources/lib/ooui/oojs-ui-core.js?f68df:11908:39 VeUiMWEditSummaryWidget@https://www.wikidata.org/w/extensions/VisualEditor/modules/ve-mw/ui/widgets/ve.ui.MWEditSummaryWidget.js?4ca0e:23:34 undefined 2 jquery.js:3841:18
Permalink to the contributions API request (i.e. based on the request made by VisualEditor that I see in the network panel, but with ucstart added so the result doesn’t change when you open it later): https://www.wikidata.org/w/api.php?action=query&format=json&list=usercontribs&formatversion=2&uclimit=500&ucstart=2021-03-13T12%3A26%3A56.000Z&ucuser=Lucas%20Werkmeister&ucprop=comment%7Ctitle
The reason for that is probably that one edit has a suppressed edit summary (I removed the ucprop so the result has more information):
$ curl -s 'https://www.wikidata.org/w/api.php?action=query&format=json&list=usercontribs&formatversion=2&uclimit=500&ucstart=2021-03-13T12%3A26%3A56.000Z&ucuser=Lucas%20Werkmeister' | jq '.query.usercontribs | .[] | select(has("comment") | not)' { "texthidden": true, "userid": 2794369, "user": "Lucas Werkmeister", "pageid": 4246474, "revid": 1342436351, "parentid": 1342434513, "ns": 0, "title": "Q4115189", "timestamp": "2021-01-16T19:30:52Z", "new": false, "minor": false, "top": false, "commenthidden": true, "size": 49539 }