Show an error message when history fails to load updates.

services/web/app/views/project/editor/history/entriesListV2.pug

@@ -3,7 +3,7 @@ aside.change-list(
 	ng-controller="HistoryV2ListController"
 )
 	history-entries-list(
-		ng-if="!history.showOnlyLabels"
+		ng-if="!history.showOnlyLabels && !history.error"
 		entries="history.updates"
 		current-user="user"
 		users="projectUsers"
@@ -15,7 +15,7 @@ aside.change-list(
 		on-label-delete="handleLabelDelete(label)"
 	)
 	history-labels-list(
-		ng-if="history.showOnlyLabels"
+		ng-if="history.showOnlyLabels && !history.error"
 		labels="history.labels"
 		current-user="user"
 		users="projectUsers"

services/web/app/views/project/editor/history/previewPanelV2.pug

@@ -77,5 +77,16 @@
 	.loading-panel(ng-show="history.selectedFile.loading")
 		i.fa.fa-spin.fa-refresh
 		|   #{translate("loading")}...
+	.error-panel(ng-show="history.error")
+		.alert.alert-danger 
+			| #{translate("generic_history_error")} 
+			a(
+				ng-href="mailto:#{settings.adminEmail}?Subject=Error%20loading%20history%20for%project%20{{ project_id }}"
+			) #{settings.adminEmail}
+			.clearfix
+				a.alert-link-as-btn.pull-right(
+					href
+					ng-click="toggleHistory()"
+			) #{translate("back_to_editor")}
 	.error-panel(ng-show="history.selectedFile.error")
 		.alert.alert-danger #{translate("generic_something_went_wrong")}

services/web/app/views/project/editor/history/toolbarV2.pug

@@ -6,14 +6,16 @@
 		i.fa.fa-spin.fa-refresh
 		|    #{translate("loading")}...
 	span.history-toolbar-selected-version(
-		ng-show="!history.loadingFileTree && !history.showOnlyLabels"
+		ng-show="!history.loadingFileTree && !history.showOnlyLabels && !history.error"
 	) #{translate("browsing_project_as_of")} 
 		time.history-toolbar-time {{ history.selection.updates[0].meta.end_ts | formatDate:'Do MMM YYYY, h:mm a' }}
 	span.history-toolbar-selected-version(
-		ng-show="!history.loadingFileTree && history.showOnlyLabels && history.selection.label"
+		ng-show="!history.loadingFileTree && history.showOnlyLabels && history.selection.label && !history.error"
 	) #{translate("browsing_project_labelled")} 
 		span.history-toolbar-selected-label "{{ history.selection.label.comment }}"
-	div.history-toolbar-actions
+	div.history-toolbar-actions(
+		ng-if="!history.error"
+	)
 		button.history-toolbar-btn(
 			ng-click="showAddLabelDialog();"
 			ng-if="!history.showOnlyLabels"
@@ -28,7 +30,9 @@
 			i.fa.fa-exchange
 			|  #{translate("compare_to_another_version")}
 
-	.history-toolbar-entries-list
+	.history-toolbar-entries-list(
+		ng-if="!history.error"
+	)
 		toggle-switch(
 			ng-model="history.showOnlyLabels"
 			label-true=translate("history_view_labels")

services/web/public/coffee/ide/history/HistoryV2Manager.coffee

@@ -92,6 +92,7 @@ define [
 						toV: null
 					}
 				}
+				error: null
 				showOnlyLabels: false
 				labels: null
 				files: []
@@ -234,6 +235,11 @@ define [
 					if !updatesData.nextBeforeTimestamp?
 						@$scope.history.atEnd = true
 					@$scope.history.loading = false
+				.catch (error) =>
+					{ status, statusText } = error
+					@$scope.history.error = { status, statusText }
+					@$scope.history.loading = false
+					@$scope.history.loadingFileTree = false
 
 		_sortLabelsByVersionAndDate: (labels) ->
 			@ide.$filter("orderBy")(labels, [ '-version', '-created_at' ])