Add case-insensitive project identifier storage

Introduce case-insensitive handling for project identifiers:

- Add `normalizes :identifier` to automatically upcase (alphanumeric
  mode) or downcase (numeric mode) identifiers on assignment
- Add `parse_friendly_id` to normalize FriendlyId lookups for
  case-insensitive finder queries
- Switch uniqueness validation to `case_sensitive: false`
- Replace inline `exclusion:` validator with explicit
  `identifier_not_reserved` that checks case-insensitively
- Consolidate alphanumeric format validators into a single
  `identifier_alphanumeric_format` method with early return to
  prevent cascading error messages
- Use case-insensitive LOWER() comparison in historical identifier
  reservation check
- Add `post_process` support to the OpActiveRecord acts_as_url
  adapter with an allowlist of safe transforms (upcase/downcase)
- Add migration to replace the unique index on projects.identifier
  with a case-insensitive LOWER(identifier) index
- Update table definition to match the new index

Includes corresponding test additions for normalization, case-
insensitive uniqueness, reserved identifier rejection, and the
create_spec fixture fix for alphanumeric mode.

Author: akabiru

app/models/projects/identifier.rb

@@ -39,37 +39,42 @@ module Projects::Identifier
     extend FriendlyId
 
     normalizes :identifier, with: OpenProject::RemoveAsciiControlCharacters
+    normalizes :identifier, with: ->(value) {
+      stripped = value.to_s.strip
+      Setting::WorkPackageIdentifier.alphanumeric? ? stripped.upcase : stripped.downcase
+    }
 
     acts_as_url :name,
                 url_attribute: :identifier,
                 sync_url: false, # Don't update identifier when name changes
                 only_when_blank: true, # Only generate when identifier not set
                 limit: IDENTIFIER_MAX_LENGTH,
+                force_downcase: false,
+                post_process: ->(_instance) {
+                  Setting::WorkPackageIdentifier.alphanumeric? ? :upcase : :downcase
+                },
                 blacklist: RESERVED_IDENTIFIERS,
                 adapter: OpenProject::ActsAsUrl::Adapter::OpActiveRecord # use a custom adapter able to handle edge cases
 
-    ### Validators for the legacy underscored identifier format (e.g. "project_one")
     validates :identifier,
               presence: true,
-              uniqueness: { case_sensitive: true },
+              uniqueness: { case_sensitive: false },
               length: { maximum: IDENTIFIER_MAX_LENGTH },
-              exclusion: RESERVED_IDENTIFIERS,
               if: ->(p) { p.persisted? || p.identifier.present? }
+
+    # Validators for the numeric identifier format (e.g. "project_one")
     # Contains only a-z, 0-9, dashes and underscores but cannot consist of numbers only as it would clash with the id.
     validates :identifier,
               format: { with: /\A(?!^\d+\z)[a-z0-9\-_]+\z/ },
               if: ->(p) {
                 p.identifier_changed? && p.identifier.present? && Setting::WorkPackageIdentifier.numeric?
               }
 
-    ### Validators for the uppercase identifier format (e.g. "PROJ1")
-    validates :identifier,
-              format: { with: /\A[A-Z]/, message: :must_start_with_letter },
-              if: ->(p) { p.identifier_changed? && p.identifier.present? && Setting::WorkPackageIdentifier.alphanumeric? }
-    validates :identifier,
-              format: { with: /\A[A-Z][A-Z0-9_]*\z/, message: :no_special_characters },
-              length: { maximum: SEMANTIC_IDENTIFIER_MAX_LENGTH },
-              if: ->(p) { p.identifier_changed? && p.identifier.present? && Setting::WorkPackageIdentifier.alphanumeric? }
+    # Validators for the alphanumeric identifier format (e.g. "PROJ1")
+    validate :identifier_alphanumeric_format,
+             if: ->(p) { p.identifier_changed? && p.identifier.present? && Setting::WorkPackageIdentifier.alphanumeric? }
+
+    validate :identifier_not_reserved, if: -> { identifier.present? }
 
     # Complements the uniqueness validation above: once an identifier has been used by a
     # project, it remains reserved for that project even after the project moves to a new
@@ -88,6 +93,12 @@ def unset_slug_if_invalid; end
   end
 
   class_methods do
+    # Normalize the input to FriendlyID finders so that lookups are case-insensitive.
+    # FriendlyID's default parse_friendly_id returns the value unchanged.
+    def parse_friendly_id(value)
+      normalize_value_for(:identifier, value)
+    end
+
     def suggest_identifier(name)
       if Setting::WorkPackageIdentifier.alphanumeric?
         WorkPackages::IdentifierAutofix::ProjectIdentifierSuggestionGenerator.suggest_identifier(name)
@@ -117,14 +128,33 @@ def validation_context
 
   private
 
+  def identifier_alphanumeric_format
+    unless identifier.match?(/\A[A-Z]/)
+      errors.add(:identifier, :must_start_with_letter)
+      return
+    end
+
+    errors.add(:identifier, :no_special_characters) unless identifier.match?(/\A[A-Z][A-Z0-9_]*\z/)
+    if identifier.length > SEMANTIC_IDENTIFIER_MAX_LENGTH
+      errors.add(:identifier, :too_long, count: SEMANTIC_IDENTIFIER_MAX_LENGTH)
+    end
+  end
+
+  def identifier_not_reserved
+    if RESERVED_IDENTIFIERS.include?(identifier&.downcase)
+      errors.add(:identifier, :exclusion)
+    end
+  end
+
   # Checks friendly_id_slugs for any project that previously used this identifier and
   # has since changed it. It allows to switch back to an identifier the project itself
-  # has used before.
+  # has used before. Uses case-insensitive comparison to prevent cross-case collisions.
   def identifier_not_historically_reserved
     return if errors.any? { |error| error.attribute == :identifier && error.type == :taken }
 
     already_existing = FriendlyId::Slug
-                         .where(slug: identifier, sluggable_type: self.class.to_s)
+                         .where("LOWER(slug) = LOWER(?)", identifier)
+                         .where(sluggable_type: self.class.to_s)
                          .where.not(sluggable_id: id)
                          .exists?
 

db/migrate/20260319120000_add_case_insensitive_uniqueness_for_project_identifiers.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
+#++
+
+class AddCaseInsensitiveUniquenessForProjectIdentifiers < ActiveRecord::Migration[8.0]
+  disable_ddl_transaction!
+
+  def up
+    remove_index :projects, :identifier, unique: true, algorithm: :concurrently, if_exists: true
+    add_index :projects, "LOWER(identifier)",
+              unique: true,
+              name: "index_projects_on_lower_identifier",
+              algorithm: :concurrently,
+              if_not_exists: true
+  end
+
+  def down
+    remove_index :projects, name: "index_projects_on_lower_identifier", algorithm: :concurrently, if_exists: true
+    add_index :projects, :identifier, unique: true, algorithm: :concurrently
+  end
+end

db/migrate/tables/projects.rb

@@ -49,7 +49,7 @@ def self.table(migration) # rubocop:disable Metrics/AbcSize
 
       t.index :lft, name: "index_projects_on_lft"
       t.index :rgt, name: "index_projects_on_rgt"
-      t.index :identifier, unique: true
+      t.index "LOWER(identifier)", unique: true, name: "index_projects_on_lower_identifier"
       t.index %i[lft rgt]
     end
   end

lib/open_project/acts_as_url/adapter/op_active_record.rb

@@ -50,6 +50,8 @@ def url_attribute(instance)
           read_attribute instance, settings.url_attribute
         end
 
+        ALLOWED_POST_TRANSFORMS = %i[upcase downcase].freeze
+
         private
 
         def modify_base_url
@@ -58,6 +60,15 @@ def modify_base_url
           self.base_url = root.to_localized_slug(locale:, **configuration.string_extensions_settings)
 
           modify_base_url_custom_rules if base_url.empty?
+          apply_post_process
+        end
+
+        def apply_post_process
+          post_process = configuration.settings.post_process
+          return unless post_process
+
+          method = post_process.respond_to?(:call) ? post_process.call(instance) : post_process
+          self.base_url = base_url.public_send(method) if method && ALLOWED_POST_TRANSFORMS.include?(method)
         end
 
         def modify_base_url_custom_rules

spec/features/projects/create_spec.rb

@@ -592,6 +592,7 @@
 
       fill_in "Name", with: "Flight Planning Algorithm"
       find("body").click
+      expect(page).to have_field "Identifier", with: "FPA"
 
       fill_in "Identifier", with: "3INVALID"
       click_on "Complete"

spec/models/project_spec.rb

@@ -606,5 +606,4 @@
       end
     end
   end
-
 end

spec/models/projects/identifier_spec.rb

@@ -28,7 +28,7 @@
 # See COPYRIGHT and LICENSE files for more details.
 #++
 
-require "spec_helper"
+require "rails_helper"
 
 RSpec.describe Projects::Identifier do
   describe "identifier normalization" do
@@ -37,7 +37,57 @@
     it { is_expected.to normalize(:identifier).from("my\n\x00project\t").to("myproject") }
   end
 
-  describe "url identifier" do
+  describe ".normalize_value_for" do
+    context "when in numeric mode (default)" do
+      before { allow(Setting::WorkPackageIdentifier).to receive(:alphanumeric?).and_return(false) }
+
+      it "downcases the value" do
+        expect(Project.normalize_value_for(:identifier, "PROJ")).to eq("proj")
+      end
+
+      it "strips whitespace" do
+        expect(Project.normalize_value_for(:identifier, "  proj  ")).to eq("proj")
+      end
+
+      it "returns nil unchanged" do
+        expect(Project.normalize_value_for(:identifier, nil)).to be_nil
+      end
+    end
+
+    context "when in alphanumeric mode" do
+      before { allow(Setting::WorkPackageIdentifier).to receive(:alphanumeric?).and_return(true) }
+
+      it "upcases the value" do
+        expect(Project.normalize_value_for(:identifier, "proj")).to eq("PROJ")
+      end
+
+      it "strips whitespace" do
+        expect(Project.normalize_value_for(:identifier, "  proj  ")).to eq("PROJ")
+      end
+    end
+  end
+
+  describe "normalizes :identifier on Project" do
+    context "when in numeric mode (default)" do
+      before { allow(Setting::WorkPackageIdentifier).to receive(:alphanumeric?).and_return(false) }
+
+      it "downcases identifier on assignment" do
+        project = Project.new(identifier: "MyProject")
+        expect(project.identifier).to eq("myproject")
+      end
+    end
+
+    context "when in alphanumeric mode" do
+      before { allow(Setting::WorkPackageIdentifier).to receive(:alphanumeric?).and_return(true) }
+
+      it "upcases identifier on assignment" do
+        project = Project.new(identifier: "myproject")
+        expect(project.identifier).to eq("MYPROJECT")
+      end
+    end
+  end
+
+  describe "url identifier", with_settings: { work_packages_identifier: "numeric" } do
     let(:reserved) do
       Rails.application.routes.routes
         .map { |route| route.path.spec.to_s }
@@ -73,6 +123,14 @@
       expect(project.errors[:identifier]).to include("has already been taken.")
     end
 
+    it "is not allowed to clash with another project case-insensitively" do
+      create(:project, identifier: "existing")
+
+      project = build(:project, identifier: "EXISTING")
+      expect(project).not_to be_valid
+      expect(project.errors[:identifier]).to include("has already been taken.")
+    end
+
     it "is not allowed to clash with a former identifier of another project" do
       other_project = create(:project, identifier: "former-id")
       other_project.update!(identifier: "new-id")
@@ -82,6 +140,15 @@
       expect(project.errors[:identifier]).to include("has already been taken.")
     end
 
+    it "is not allowed to clash with a former identifier of another project case-insensitively" do
+      other_project = create(:project, identifier: "former-id")
+      other_project.update!(identifier: "new-id")
+
+      project = build(:project, identifier: "FORMER-ID")
+      expect(project).not_to be_valid
+      expect(project.errors[:identifier]).to include("has already been taken.")
+    end
+
     it "is allowed to be the same as its own former identifier" do
       project = create(:project, identifier: "old-id")
       project.update!(identifier: "new-id")
@@ -90,6 +157,12 @@
       expect(project).to be_valid
     end
 
+    it "rejects reserved identifiers case-insensitively" do
+      project = build(:project, identifier: "NEW")
+      expect(project).not_to be_valid
+      expect(project.errors[:identifier]).to include("is reserved.")
+    end
+
     # The acts_as_url plugin defines validation callbacks on :create and it is not automatically
     # called when calling a custom context. However we need the acts_as_url callback to set the
     # identifier when the validations are called with the :saving_custom_fields context.