Fix: only flexibleRollout strategy should use defaults

src/lib/features/client-feature-toggles/tests/__snapshots__/client-feature-toggles.e2e.test.ts.snap

@@ -54,9 +54,7 @@ exports[`should match snapshot from /api/client/features 1`] = `
             },
           ],
           "name": "default",
-          "parameters": {
-            "stickiness": "default",
-          },
+          "parameters": {},
           "variants": [],
         },
       ],

src/lib/features/client-feature-toggles/tests/client-feature-toggles.e2e.test.ts

@@ -70,9 +70,7 @@ const getApiClientResponse = (project = 'default') => [
                         values: ['123'],
                     },
                 ],
-                parameters: {
-                    stickiness: 'default',
-                },
+                parameters: {},
                 variants: [],
             },
         ],

src/lib/features/feature-toggle/feature-toggle-service.ts

@@ -117,7 +117,7 @@ import { sortStrategies } from '../../util/sortStrategies.js';
 import type { ResourceLimitsSchema } from '../../openapi/index.js';
 import type FeatureLinkService from '../feature-links/feature-link-service.js';
 import type { IFeatureLink } from '../feature-links/feature-links-read-model-type.js';
-
+import merge from 'deepmerge';
 interface IFeatureContext {
     featureName: string;
     projectId: string;
@@ -126,6 +126,9 @@ interface IFeatureContext {
 interface IFeatureStrategyContext extends IFeatureContext {
     environment: string;
 }
+function mergeAll<T>(objects: Partial<T>[]): T {
+    return merge.all<T>(objects.filter((i) => i));
+}
 
 export interface IGetFeatureParams {
     featureName: string;
@@ -670,7 +673,48 @@ export class FeatureToggleService {
         );
     }
 
-    async standardizeStrategyConfig(
+    private async defaultParameters(
+        projectId: string,
+        strategyName: string,
+        featureName: string,
+        params: IFeatureStrategy['parameters'] | undefined,
+    ) {
+        if (strategyName === 'flexibleRollout') {
+            if (params?.stickiness === '') {
+                // If stickiness is an empty string, we remove it to use the default stickiness.
+                delete params?.stickiness;
+            }
+            return {
+                rollout: '100',
+                stickiness:
+                    params?.stickiness ??
+                    (await this.featureStrategiesStore.getDefaultStickiness(
+                        projectId,
+                    )),
+                groupId: featureName,
+            };
+        } else {
+            /// We don't really have good defaults for the other kinds of known strategies, so return an empty map.
+            return {};
+        }
+    }
+    private async parametersWithDefaults(
+        projectId: string,
+        strategyName: string,
+        featureName: string,
+        params: IFeatureStrategy['parameters'] | undefined,
+    ) {
+        return mergeAll([
+            await this.defaultParameters(
+                projectId,
+                strategyName,
+                featureName,
+                params,
+            ),
+            params ?? {},
+        ]);
+    }
+    private async standardizeStrategyConfig(
         projectId: string,
         strategyConfig: Unsaved<IStrategyConfig>,
         existing?: IFeatureStrategy,
@@ -695,18 +739,12 @@ export class FeatureToggleService {
             constraints = await this.validateConstraints(constraints);
         }
 
-        if (
-            parameters &&
-            (!('stickiness' in parameters) ||
-                ('stickiness' in parameters && parameters.stickiness === ''))
-        ) {
-            parameters.stickiness =
-                existing?.parameters?.stickiness ||
-                (await this.featureStrategiesStore.getDefaultStickiness(
-                    projectId,
-                ));
-        }
-
+        parameters = await this.parametersWithDefaults(
+            projectId,
+            name,
+            strategyConfig.featureName!,
+            strategyConfig.parameters,
+        );
         if (variants && variants.length > 0) {
             await variantsArraySchema.validateAsync(variants);
             const fixedVariants = this.fixVariantWeights(variants);

src/lib/features/feature-toggle/feature-toggle-strategies-store.ts

@@ -28,7 +28,6 @@ import {
 import type { IFeatureProjectUserParams } from './feature-toggle-controller.js';
 import type { Db } from '../../db/db.js';
 import { isAfter } from 'date-fns';
-import merge from 'deepmerge';
 import Raw = Knex.Raw;
 import type { ITag } from '../../tags/index.js';
 
@@ -157,32 +156,6 @@ function mapStrategyUpdate(
     return update;
 }
 
-function mergeAll<T>(objects: Partial<T>[]): T {
-    return merge.all<T>(objects.filter((i) => i));
-}
-
-const defaultParameters = (
-    params: PartialSome<IFeatureStrategy, 'id' | 'createdAt'>,
-    stickiness: string,
-) => {
-    if (params.strategyName === 'flexibleRollout') {
-        return {
-            rollout: '100',
-            stickiness,
-            groupId: params.featureName,
-        };
-    } else {
-        /// We don't really have good defaults for the other kinds of known strategies, so return an empty map.
-        return {};
-    }
-};
-
-const parametersWithDefaults = (
-    params: PartialSome<IFeatureStrategy, 'id' | 'createdAt'>,
-    stickiness: string,
-) => {
-    return mergeAll([defaultParameters(params, stickiness), params.parameters]);
-};
 class FeatureStrategiesStore implements IFeatureStrategiesStore {
     private db: Db;
 
@@ -264,13 +237,6 @@ class FeatureStrategiesStore implements IFeatureStrategiesStore {
                 strategyConfig.featureName,
                 strategyConfig.environment,
             ));
-        const stickiness =
-            strategyConfig.parameters?.stickiness ??
-            (await this.getDefaultStickiness(strategyConfig.projectId));
-        strategyConfig.parameters = parametersWithDefaults(
-            strategyConfig,
-            stickiness,
-        );
         const strategyRow = mapInput({
             id: uuidv4(),
             ...strategyConfig,