Format dates according to instance setting

We default to the ISO8601 format, if the instance
set no preference, but otherwise we use the instance's
preference.

app/models/work_package_types/patterns/token_property_mapper.rb

@@ -33,7 +33,7 @@ module WorkPackageTypes
     class TokenPropertyMapper
       STRING_OR_NIL = ->(v) { v&.to_s }
       ARRAY = ->(v) { v.compact.presence&.join(", ") }
-      DATE = ->(v) { v&.strftime("%Y-%m-%d") }
+      DATE = ->(v) { v&.strftime(Setting.date_format || "%Y-%m-%d") }
       DURATION = ->(v) { DurationConverter.output(v) }
 
       class << self
@@ -120,11 +120,13 @@ module WorkPackageTypes
       end
 
       def tokenize(custom_field_scope, prefix = nil)
-        custom_field_scope.pluck(:name, :id, :multi_value).map do |name, id, multiple|
+        custom_field_scope.pluck(:name, :id, :field_format, :multi_value).map do |name, id, format, multiple|
           formatter = if multiple
                         ARRAY
+                      elsif format == "date"
+                        DATE
                       else
-                        ->(v) { v.is_a?(Symbol) ? v : v&.to_s }
+                        ->(v) { v.is_a?(Symbol) ? v : STRING_OR_NIL.call(v) }
                       end
           AttributeToken.new(
             :"#{prefix}custom_field_#{id}",

spec/models/work_package_types/patterns/token_property_mapper_spec.rb

@@ -133,7 +133,7 @@ RSpec.describe WorkPackageTypes::Patterns::TokenPropertyMapper do
       expect(token.call(work_package)).to eq("false")
     end
 
-    it "formats date custom fields correctly" do
+    it "formats date custom fields with a default format" do
       enabled, = subject
       token = enabled.detect do |t|
         t.key == :"custom_field_#{date_custom_field.id}"
@@ -175,6 +175,17 @@ RSpec.describe WorkPackageTypes::Patterns::TokenPropertyMapper do
       expect(detect(enabled, :"custom_field_#{cf.id}")).to be_nil
       expect(detect(disabled, :"custom_field_#{cf.id}")&.label).to eq(cf.name)
     end
+
+    context "when defining an instance date format", with_settings: { date_format: "%d.%m.%Y" } do
+      it "formats date custom fields according to the instance date format" do
+        enabled, = subject
+        token = enabled.detect do |t|
+          t.key == :"custom_field_#{date_custom_field.id}"
+        end
+
+        expect(token.call(work_package)).to eq("03.10.2025")
+      end
+    end
   end
 
   private