[63475] Preserve unset dates when moving work packages in calendar

https://community.openproject.org/wp/63475

If it's resized, both start and due dates are set.

If it's dragged and dropped and it's a milestone, it's the same as
resizing: both dates are set.

If it's dragged and dropped and it's not a milestone, if it has a
duration, set duration and start date to deal with non-working days, and
if it has no duration, set start date if it was already set, or set the
due date.

frontend/src/app/features/calendar/op-work-packages-calendar.service.ts

@@ -432,16 +432,40 @@ export class OpWorkPackagesCalendarService extends UntilDestroyedMixin {
 
   updateDates(resizeInfo:EventResizeDoneArg|EventDropArg|EventReceiveArg, dragged?:boolean):ResourceChangeset<WorkPackageResource> {
     const workPackage = resizeInfo.event.extendedProps.workPackage as WorkPackageResource;
-    const changeset = this.halEditing.edit(workPackage);
-    if (!workPackage.ignoreNonWorkingDays && workPackage.duration && dragged) {
-      changeset.setValue('duration', workPackage.duration);
-    } else {
-      const due = moment(resizeInfo.event.endStr)
-        .subtract(1, 'day')
-        .format('YYYY-MM-DD');
-      changeset.setValue('dueDate', due);
+    const startDate = resizeInfo.event.startStr;
+    const endDate = moment(resizeInfo.event.endStr).subtract(1, 'day').format('YYYY-MM-DD');
+
+    if (dragged && !this.isMilestone(workPackage)) {
+      return this.moveToDates(workPackage, startDate, endDate);
     }
-    changeset.setValue('startDate', resizeInfo.event.startStr);
+    return this.changeToDates(workPackage, startDate, endDate);
+  }
+
+  private moveToDates(workPackage:WorkPackageResource, startDate:string, endDate:string):ResourceChangeset<WorkPackageResource> {
+    const changeset = this.halEditing.edit(workPackage);
+
+    // Due to non-working days, we can't directly set start and due date when
+    // drag-n-dropping work packages. Instead set duration (if present) and
+    // start date to get due date recomputed.
+    if (workPackage.duration) {
+      changeset.setValue('duration', workPackage.duration);
+    }
+
+    // Keep dates unset if they are not set
+    if (workPackage.startDate) {
+      changeset.setValue('startDate', startDate);
+    } else {
+      changeset.setValue('dueDate', endDate);
+    }
+
+    return changeset;
+  }
+
+  private changeToDates(workPackage:WorkPackageResource, startDate:string, endDate:string):ResourceChangeset<WorkPackageResource> {
+    const changeset = this.halEditing.edit(workPackage);
+    changeset.setValue('startDate', startDate);
+    changeset.setValue('dueDate', endDate);
+
     return changeset;
   }
 }

modules/calendar/spec/features/calendar_user_interaction_spec.rb

@@ -34,17 +34,16 @@ RSpec.describe "Calendar drag&dop and resizing",
                :selenium do
   include_context "with calendar full access"
 
-  let!(:other_user) do
-    create(:user,
-           firstname: "Bernd",
-           member_with_permissions: { project => %w[view_work_packages view_calendar] })
-  end
-
-  let!(:work_package) do
+  shared_let(:monday) { Time.zone.today.beginning_of_week }
+  shared_let(:tuesday) { monday + 1.day }
+  shared_let(:wednesday) { monday + 2.days }
+  shared_let(:thursday) { monday + 3.days }
+  shared_let(:friday) { monday + 4.days }
+  shared_let(:work_package) do
     create(:work_package,
            project:,
-           start_date: Time.zone.today.beginning_of_week.next_occurring(:tuesday),
-           due_date: Time.zone.today.beginning_of_week.next_occurring(:thursday))
+           start_date: tuesday,
+           due_date: thursday)
   end
 
   before do
@@ -55,11 +54,10 @@ RSpec.describe "Calendar drag&dop and resizing",
 
   context "with full permissions" do
     it "allows to resize to change the dates of a wp" do
-      target = work_package.due_date + 1.day
+      target = friday
       current_start = work_package.start_date
-      retry_block do
-        calendar.resize_date(work_package, target)
-      end
+
+      calendar.resize_end_date(work_package, target)
 
       calendar.expect_and_dismiss_toaster(message: I18n.t("js.notice_successful_update"))
 
@@ -69,12 +67,10 @@ RSpec.describe "Calendar drag&dop and resizing",
     end
 
     it "allows to resize from the start" do
-      target = work_package.start_date - 1.day
+      target = monday
       current_end = work_package.due_date
 
-      retry_block do
-        calendar.resize_date(work_package, target, end_date: false)
-      end
+      calendar.resize_start_date(work_package, target)
 
       calendar.expect_and_dismiss_toaster(message: I18n.t("js.notice_successful_update"))
 
@@ -84,13 +80,9 @@ RSpec.describe "Calendar drag&dop and resizing",
     end
 
     it "allows to drag the work package to another date" do
-      target = Time.zone.today.beginning_of_week
+      target = monday
 
-      retry_block do
-        calendar.drag_event(work_package, target)
-      end
-
-      calendar.expect_and_dismiss_toaster(message: I18n.t("js.notice_successful_update"))
+      calendar.drag_event(work_package, target)
 
       work_package.reload
 
@@ -98,9 +90,39 @@ RSpec.describe "Calendar drag&dop and resizing",
       expect(work_package.start_date).to eq(target - 1.day)
       expect(work_package.due_date).to eq(target + 1.day)
     end
+
+    context "with work packages having only start or due date" do
+      shared_let(:start_only_wp) do
+        create(:work_package,
+               subject: "Start only",
+               project:,
+               start_date: tuesday)
+      end
+      shared_let(:due_only_wp) do
+        create(:work_package,
+               subject: "Due only",
+               project:,
+               due_date: thursday)
+      end
+
+      it "keeps one date set and the other unset when dragging them to another date (Bug #63475)" do
+        # move start_only_wp to wednesday
+        calendar.drag_event(start_only_wp, wednesday)
+        expect(start_only_wp.reload).to have_attributes(start_date: wednesday, due_date: nil)
+
+        # move due_only_wp to wednesday
+        calendar.drag_event(due_only_wp, wednesday)
+        expect(due_only_wp.reload).to have_attributes(start_date: nil, due_date: wednesday)
+      end
+    end
   end
 
   context "without permission to edit" do
+    let(:other_user) do
+      create(:user,
+             firstname: "Bernd",
+             member_with_permissions: { project => %w[view_work_packages view_calendar] })
+    end
     let(:current_user) { other_user }
 
     it "allows neither dragging nor resizing any wp" do

modules/calendar/spec/support/pages/calendar.rb

@@ -57,6 +57,14 @@ module Pages
       ::Pages::SplitWorkPackageCreate.new project:
     end
 
+    def resize_start_date(work_package, date)
+      resize_date(work_package, date, end_date: false)
+    end
+
+    def resize_end_date(work_package, date)
+      resize_date(work_package, date, end_date: true)
+    end
+
     def resize_date(work_package, date, end_date: true)
       retry_block do
         wp_strip = event(work_package)
@@ -81,6 +89,7 @@ module Pages
       end_container = date_container target
 
       drag_n_drop_element(from: start_container, to: end_container)
+      expect_and_dismiss_toaster(message: I18n.t("js.notice_successful_update"))
     end
 
     def date_container(date)