DEV: show no icon if icon name is missing and log at error level (#31866)

On 1st April 2025, we start showing no icons if the icon name used is a
deprecated one and therefore no longer part of the svg set.

We'll continue showing the messages with the correct icon name to aid
correction of these names.

Console logging will now be done at an error level for such icons.

We retain the behaviour of raising an error for such icons in plugins
from svg_sprite.rb in test environments, but removed this from
icon-library.js as it's harder to test the actual expected behaviour of
returning the original icon now that it's not part of the deprecation
workflow. (sinon.stub doesn't work well here for `isTesting` - the
alternative would be to override the environment.js module with
`proxyquire`) In any case, once we remove the mapping logic, we won't be
raising errors in test environment either for this scenario.

app/assets/javascripts/discourse/app/lib/icon-library.js

@@ -1,11 +1,7 @@
 import { h } from "virtual-dom";
 import attributeHook from "discourse/lib/attribute-hook";
 import deprecated from "discourse/lib/deprecated";
-import {
-  isDevelopment,
-  isRailsTesting,
-  isTesting,
-} from "discourse/lib/environment";
+import { isDevelopment } from "discourse/lib/environment";
 import escape from "discourse/lib/escape";
 import { i18n } from "discourse-i18n";
 
@@ -146,17 +142,13 @@ function handleDeprecatedIcon(id) {
   newId = remapFromFA5(newId);
 
   if (newId !== id) {
-    deprecated(
-      `The icon name "${id}" has been updated to "${newId}". Please use the new name in your code. Old names will be removed in Q2 2025.`,
-      {
-        id: "discourse.fontawesome-6-upgrade",
-        url: "https://meta.discourse.org/t/325349",
-        raiseError: isTesting() || isRailsTesting(),
-      }
-    );
+    const error_msg = `Missing icon error: The icon name "${id}" has been removed and should be updated to "${newId}" in your code. More info at https://meta.discourse.org/t/325349.`;
+
+    // eslint-disable-next-line no-console
+    console.error(error_msg);
   }
 
-  return newId;
+  return id;
 }
 
 function warnIfMissing(id) {

app/assets/javascripts/discourse/app/services/deprecation-warning-handler.js

@@ -19,7 +19,6 @@ export const CRITICAL_DEPRECATIONS = [
   "discourse.header-widget-overrides",
   "discourse.plugin-outlet-tag-name",
   "discourse.post-menu-widget-overrides",
-  "discourse.fontawesome-6-upgrade",
   "discourse.add-flag-property",
   "discourse.breadcrumbs.childCategories",
   "discourse.breadcrumbs.firstCategory",

app/assets/javascripts/discourse/tests/unit/lib/icon-library-test.js

@@ -1,15 +1,10 @@
 import { setupTest } from "ember-qunit";
 import { module, test } from "qunit";
-import { withSilencedDeprecations } from "discourse/lib/deprecated";
 import {
   convertIconClass,
   iconHTML,
   iconNode,
 } from "discourse/lib/icon-library";
-import {
-  disableRaiseOnDeprecation,
-  enableRaiseOnDeprecation,
-} from "discourse/tests/helpers/raise-on-deprecation";
 
 module("Unit | Utility | icon-library", function (hooks) {
   setupTest(hooks);
@@ -52,13 +47,9 @@ module("Unit | Utility | icon-library", function (hooks) {
   });
 
   test("fa5 remaps", function (assert) {
-    withSilencedDeprecations("discourse.fontawesome-6-upgrade", () => {
     const adjustIcon = iconHTML("adjust");
     assert.true(adjustIcon.includes("d-icon-adjust"), "class is maintained");
-      assert.true(
-        adjustIcon.includes('href="#circle-half-stroke"'),
-        "has remapped icon"
-      );
+    assert.true(adjustIcon.includes('href="#adjust"'), "keeps original icon");
 
     const farIcon = iconHTML("far-dot-circle");
     assert.true(
@@ -66,29 +57,8 @@ module("Unit | Utility | icon-library", function (hooks) {
       "class is maintained"
     );
     assert.true(
-        farIcon.includes('href="#far-circle-dot"'),
-        "has remapped icon"
+      farIcon.includes('href="#far-dot-circle"'),
+      "keeps original icon"
     );
   });
 });
-
-  test("fa5 remaps throws error", function (assert) {
-    disableRaiseOnDeprecation();
-    assert.throws(
-      () => {
-        iconHTML("adjust");
-      },
-      /Deprecation notice: The icon name "adjust" has been updated to "circle-half-stroke".*\[deprecation id: discourse\.fontawesome-6-upgrade\]/,
-      "throws an error if icon name is deprecated"
-    );
-
-    assert.throws(
-      () => {
-        iconHTML("far-dot-circle");
-      },
-      /Deprecation notice: The icon name "far-dot-circle" has been updated to "far-circle-dot".*\[deprecation id: discourse\.fontawesome-6-upgrade\]/,
-      "throws an error if icon name is deprecated"
-    );
-    enableRaiseOnDeprecation();
-  });
-});

lib/deprecated_icon_handler.rb

@@ -687,11 +687,12 @@ module DeprecatedIconHandler
     new_name = remap_from_fa5(new_name)
 
     if icon_name != new_name
-      Discourse.deprecate(
-        "The icon `#{icon_name}` is deprecated. Use `#{new_name}` instead.",
-        raise_error: Rails.env.test?,
-      )
-      return new_name
+      error_msg =
+        `Missing icon error: The icon name "#{icon_name}" has been removed and should be updated to "#{new_name}" in your code. More info at https://meta.discourse.org/t/325349.`
+
+      Rails.logger.error(error_msg)
+
+      raise Discourse::MissingIconError.new(error_msg) if Rails.env.test?
     end
 
     icon_name

lib/discourse.rb

@@ -117,6 +117,7 @@ module Discourse
 
     class CommandError < RuntimeError
       attr_reader :status, :stdout, :stderr
+
       def initialize(message, status: nil, stdout: nil, stderr: nil)
         super(message)
         @status = status
@@ -305,6 +306,9 @@ module Discourse
   class Deprecation < StandardError
   end
 
+  class MissingIconError < StandardError
+  end
+
   class ScssError < StandardError
   end
 

spec/lib/svg_sprite/svg_sprite_spec.rb

@@ -88,18 +88,18 @@ RSpec.describe SvgSprite do
 
   it "strips whitespace when processing icons" do
     Fabricate(:badge, name: "Custom Icon Badge", icon: "  fab fa-facebook-messenger  ")
-    expect(SvgSprite.all_icons).to include("fab-facebook-messenger")
-    expect(SvgSprite.all_icons).not_to include("  fab-facebook-messenger  ")
+    expect(SvgSprite.all_icons).to include("fab fa-facebook-messenger")
+    expect(SvgSprite.all_icons).not_to include("  fab fa-facebook-messenger  ")
   end
 
-  it "includes Font Awesome 5 icons from badges" do
+  it "includes icons from badges" do
     Fabricate(:badge, name: "Custom Icon Badge", icon: "far fa-building")
-    expect(SvgSprite.all_icons).to include("far-building")
+    expect(SvgSprite.all_icons).to include("far fa-building")
   end
 
   it "raises an error in test for deprecated icons" do
     allow(Rails.env).to receive(:test?).and_return(true)
-    expect { SvgSprite.search("fa-gamepad") }.to raise_error(Discourse::Deprecation)
+    expect { SvgSprite.search("fa-gamepad") }.to raise_error(Discourse::MissingIconError)
   end
 
   it "includes icons defined in theme settings" do
@@ -127,7 +127,7 @@ RSpec.describe SvgSprite do
     # FA5 syntax
     theme.update_setting(:custom_icon, "fab fa-bandcamp")
     theme.save!
-    expect(SvgSprite.all_icons(theme.id)).to include("fab-bandcamp")
+    expect(SvgSprite.all_icons(theme.id)).to include("fab fa-bandcamp")
 
     # Internal Discourse syntax + multiple icons
     theme.update_setting(:custom_icon, "fab-android|dragon")
@@ -227,7 +227,7 @@ RSpec.describe SvgSprite do
     DiscoursePluginRegistry.register_svg_icon "fab fa-bandcamp"
 
     expect(SvgSprite.all_icons).to include("blender")
-    expect(SvgSprite.all_icons).to include("fab-bandcamp")
+    expect(SvgSprite.all_icons).to include("fab fa-bandcamp")
   end
 
   it "includes Font Awesome icon from groups" do