fix: timezones on edit

app/javascript/js/controllers/fields/date_field_controller.js

@@ -204,18 +204,22 @@ export default class extends Controller {
       return
     }
 
+    const timezonedDate = DateTime.fromISO(selectedDates[0].toISOString())
+      .setZone(this.displayTimezone, { keepLocalTime: true })
+      .setZone('UTC', { keepLocalTime: !this.relativeValue })
+
     let value
     switch (this.fieldTypeValue) {
       case 'time':
         // For time values, we should maintain the real value and format it to a time-friendly format.
-        value = DateTime.fromISO(selectedDates[0].toISOString()).setZone('UTC', { keepLocalTime: !this.relativeValue }).toFormat(RAW_TIME_FORMAT)
+        value = timezonedDate.toFormat(RAW_TIME_FORMAT)
         break
       case 'date':
-        value = DateTime.fromISO(selectedDates[0].toISOString()).setZone('UTC', { keepLocalTime: true }).toFormat(RAW_DATE_FORMAT)
+        value = timezonedDate.toFormat(RAW_DATE_FORMAT)
         break
       default:
       case 'dateTime':
-        value = DateTime.fromISO(selectedDates[0].toISOString()).setZone('UTC', { keepLocalTime: !this.relativeValue }).toISO()
+        value = timezonedDate.toISO()
         break
     }
 

lib/avo/fields/date_time_field.rb

@@ -43,19 +43,26 @@ def fill_field(model, key, value, params)
       end
 
       def utc_time(value)
-        if timezone.present?
-          ActiveSupport::TimeZone.new(timezone).local_to_utc(Time.parse(value))
+        time = Time.parse(value)
+
+        if timezone.present? && !time.utc?
+          ActiveSupport::TimeZone.new(timezone).local_to_utc(time)
         else
           value
         end
       end
 
       def timezone
-        if @timezone.respond_to?(:call)
+        timezone = if @timezone.respond_to?(:call)
           return Avo::Hosts::ResourceViewRecordHost.new(block: @timezone, record: resource.model, resource: resource, view: view).handle
+        else
+          @timezone
         end
 
-        @timezone
+        # Fix for https://github.com/moment/luxon/issues/1358#issuecomment-2017477897
+        return "Etc/UTC" if timezone&.downcase == "utc" && view.in?([:new, :create, :edit, :update])
+
+        timezone
       end
     end
   end

spec/system/avo/date_time_fields/timezone_spec.rb

@@ -0,0 +1,128 @@
+require "rails_helper"
+
+# Please use the reset_browser helpers before the first and after the last spec.
+RSpec.describe "timezone", type: :system do
+  let!(:project) { create :project, started_at: Time.new(2024, 3, 25, 8, 23, 0, "UTC") } # "March 25, 2024 08:23:00 UTC"
+
+  subject(:text_input) { find '[data-field-id="started_at"] [data-controller="date-field"] input[type="text"]' }
+
+  after do
+    ProjectResource.restore_items_from_backup
+  end
+
+  describe "On Romania (EET) with CET timezone configured", tz: "Europe/Bucharest" do
+    before do
+      ProjectResource.with_temporary_items do
+        field :started_at, as: :date_time, timezone: "CET", time_24hr: true, format: "MMMM dd, y HH:mm:ss z"
+      end
+    end
+
+    it { reset_browser }
+
+    context "index" do
+      it "displays the date in CET tz" do
+        visit "/admin/resources/projects"
+
+        expect(field_element_by_resource_id(:started_at, project.id).text).to eq "March 25, 2024 09:23:00 CET"
+      end
+    end
+
+    context "show" do
+      it "displays the date in CET tz" do
+        visit "/admin/resources/projects/#{project.id}"
+
+        expect(find_field_value_element(:started_at).text).to eq "March 25, 2024 09:23:00 CET"
+      end
+    end
+
+    context "edit" do
+      describe "when keeping the value" do
+        it "saves the valid date" do
+          visit "/admin/resources/projects/#{project.id}/edit"
+
+          expect(text_input.value).to eq "2024-03-25 09:23:00"
+
+          save
+
+          expect(find_field_value_element(:started_at).text).to eq "March 25, 2024 09:23:00 CET"
+        end
+      end
+
+      describe "when changing the value" do
+        it "saves the valid date" do
+          visit "/admin/resources/projects/#{project.id}/edit"
+
+          expect(text_input.value).to eq "2024-03-25 09:23:00"
+
+          open_picker
+          set_picker_minute 24
+          set_picker_second 17
+
+          close_picker
+
+          save
+
+          expect(find_field_value_element(:started_at).text).to eq "March 25, 2024 09:24:17 CET"
+        end
+      end
+    end
+  end
+
+  describe "On Romania (EET) with UTC timezone configured", tz: "Europe/Bucharest" do
+    before do
+      ProjectResource.with_temporary_items do
+        field :started_at, as: :date_time, timezone: "UTC", time_24hr: true, format: "MMMM dd, y HH:mm:ss z"
+      end
+    end
+
+    it { reset_browser }
+
+    context "index" do
+      it "displays the date in UTC tz" do
+        visit "/admin/resources/projects"
+
+        expect(field_element_by_resource_id(:started_at, project.id).text).to eq "March 25, 2024 08:23:00 UTC"
+      end
+    end
+
+    context "show" do
+      it "displays the date in UTC tz" do
+        visit "/admin/resources/projects/#{project.id}"
+
+        expect(find_field_value_element(:started_at).text).to eq "March 25, 2024 08:23:00 UTC"
+      end
+    end
+
+    context "edit" do
+      describe "when keeping the value" do
+        it "saves the valid date" do
+          visit "/admin/resources/projects/#{project.id}/edit"
+
+          expect(text_input.value).to eq "2024-03-25 08:23:00"
+
+          save
+
+          expect(find_field_value_element(:started_at).text).to eq "March 25, 2024 08:23:00 UTC"
+        end
+      end
+
+      describe "when changing the value" do
+        it "saves the valid date" do
+          visit "/admin/resources/projects/#{project.id}/edit"
+
+          expect(text_input.value).to eq "2024-03-25 08:23:00"
+
+          open_picker
+          set_picker_minute 24
+          set_picker_second 17
+
+          close_picker
+
+          save
+
+          expect(find_field_value_element(:started_at).text).to eq "March 25, 2024 08:24:17 UTC"
+        end
+      end
+    end
+  end
+end