Fixed settings reinit to only emit changed settings events (#12184)

closes #12038

Previously we were emitting changed events for _all_ settings which would
cause any listeners for those to be triggered, this ensures that listeners are
only triggered if the corresponding setting, _did_ in fact change.

core/server/services/settings/index.js

@@ -12,11 +12,19 @@ module.exports = {
     },
 
     async reinit() {
+        const oldSettings = SettingsCache.getAll();
+
         SettingsCache.shutdown();
         const settingsCollection = await models.Settings.populateDefaults();
-        SettingsCache.init(settingsCollection);
+        const newSettings = SettingsCache.init(settingsCollection);
+
         for (const model of settingsCollection.models) {
-            model.emitChange(model.attributes.key + '.' + 'edited', {});
+            const key = model.attributes.key;
+
+            // The type of setting is object. That's why we need to compare the value of the `value` property.
+            if (newSettings[key].value !== oldSettings[key].value) {
+                model.emitChange(key + '.' + 'edited', {});
+            }
         }
     },
 

test/unit/server/settings_spec.js

@@ -0,0 +1,106 @@
+const sinon = require('sinon');
+const should = require('should');
+const rewire = require('rewire');
+const settings = rewire('../../../core/server/services/settings');
+
+describe('UNIT: server settings', function () {
+    afterEach(function () {
+        sinon.restore();
+    });
+
+    describe('reinit', function () {
+        function setupSettings(oldSettings, newSettings) {
+            const spy = sinon.spy();
+            const models = {
+                Settings: {
+                    populateDefaults: sinon.stub()
+                }
+            };
+            models.Settings.populateDefaults.resolves({
+                models: [{
+                    attributes: {
+                        key: 'db_hash'
+                    },
+                    emitChange: spy
+                }]
+            });
+
+            const cache = {
+                getAll: sinon.stub(),
+                init: sinon.stub(),
+                shutdown: sinon.stub()
+            };
+
+            cache.getAll.returns(oldSettings);
+            cache.init.returns(newSettings);
+
+            settings.__set__({
+                models,
+                SettingsCache: cache
+            });
+
+            return spy;
+        }
+
+        it('emit is not fired when the settings value is same', async function () {
+            const oldSettings = {
+                db_hash: {
+                    id: '5f4e32961c5a161b10dbff99',
+                    group: 'core',
+                    key: 'db_hash',
+                    value: '342c470a-d4e2-4aa1-9dd3-fb5f11d82db6',
+                    type: 'string',
+                    flags: null,
+                    created_at: '2020-09-01T11:37:58.000Z',
+                    created_by: '1',
+                    updated_at: '2020-09-01T11:37:58.000Z',
+                    updated_by: '1'
+                }
+            };
+            const newSettings = oldSettings;
+
+            const spy = setupSettings(oldSettings, newSettings);
+
+            await settings.reinit();
+
+            spy.calledWith('db_hash.edited', {}).should.not.be.true();
+        });
+
+        it('emit is fired when the settings value is changed', async function () {
+            const oldSettings = {
+                db_hash: {
+                    id: '5f4e32961c5a161b10dbff99',
+                    group: 'core',
+                    key: 'db_hash',
+                    value: '342c470a-d4e2-4aa1-9dd3-fb5f11d82db6',
+                    type: 'string',
+                    flags: null,
+                    created_at: '2020-09-01T11:37:58.000Z',
+                    created_by: '1',
+                    updated_at: '2020-09-01T11:37:58.000Z',
+                    updated_by: '1'
+                }
+            };
+            const newSettings = {
+                db_hash: {
+                    id: '5f4e32961c5a161b10dbff99',
+                    group: 'core',
+                    key: 'db_hash',
+                    value: '12345', // changed
+                    type: 'string',
+                    flags: null,
+                    created_at: '2020-09-01T11:37:58.000Z',
+                    created_by: '1',
+                    updated_at: '2020-09-01T11:37:58.000Z',
+                    updated_by: '1'
+                }
+            };
+
+            const spy = setupSettings(oldSettings, newSettings);
+
+            await settings.reinit();
+
+            spy.calledWith('db_hash.edited', {}).should.be.true();
+        });
+    });
+});