[AI-FSSDK] [FSSDK-12813] Normalize decision event campaign_id, variation_id, and entity_id

core-api/src/main/java/com/optimizely/ab/event/internal/EventFactory.java

@@ -1,6 +1,6 @@
 /**
  *
- *    Copyright 2016-2020, 2022, Optimizely and contributors
+ *    Copyright 2016-2020, 2022, 2026, Optimizely and contributors
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -97,18 +97,23 @@ private static Visitor createVisitor(ImpressionEvent impressionEvent) {
 
         UserContext userContext = impressionEvent.getUserContext();
 
+        String normalizedCampaignId = EventIdNormalizer.normalizeCampaignId(
+            impressionEvent.getLayerId(), impressionEvent.getExperimentId());
+        String normalizedVariationId = EventIdNormalizer.normalizeVariationId(
+            impressionEvent.getVariationId());
+
         Decision decision = new Decision.Builder()
-            .setCampaignId(impressionEvent.getLayerId())
+            .setCampaignId(normalizedCampaignId)
             .setExperimentId(impressionEvent.getExperimentId())
-            .setVariationId(impressionEvent.getVariationId())
+            .setVariationId(normalizedVariationId)
             .setMetadata(impressionEvent.getMetadata())
             .setIsCampaignHoldback(false)
             .build();
 
         Event event = new Event.Builder()
             .setTimestamp(impressionEvent.getTimestamp())
             .setUuid(impressionEvent.getUUID())
-            .setEntityId(impressionEvent.getLayerId())
+            .setEntityId(normalizedCampaignId)
             .setKey(ACTIVATE_EVENT_KEY)
             .setType(ACTIVATE_EVENT_KEY)
             .build();

core-api/src/main/java/com/optimizely/ab/event/internal/EventIdNormalizer.java

@@ -0,0 +1,111 @@
+/**
+ *
+ *    Copyright 2026, Optimizely and contributors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package com.optimizely.ab.event.internal;
+
+/**
+ * EventIdNormalizer normalizes decision-event identifier fields prior to wire serialization.
+ *
+ * <ul>
+ *   <li>{@code campaign_id} and impression {@code entity_id} must be a non-empty
+ *       string of any character content (IDs may be opaque, e.g. {@code "default-12345"},
+ *       {@code "layer_abc"}). If null or empty string, substitute {@code experiment_id}.
+ *       Non-numeric strings pass through unchanged.</li>
+ *   <li>{@code variation_id} must be a non-empty decimal-digit string OR {@code null}.
+ *       If empty / non-numeric / whitespace, substitute {@code null}. This field retains
+ *       the stricter numeric-string-only contract.</li>
+ * </ul>
+ *
+ * <p>For {@code variation_id}, a "numeric string" is a non-empty string consisting
+ * entirely of decimal digits {@code [0-9]}. Leading zeros are allowed. Whitespace,
+ * negatives, decimals, and exponents are INVALID.
+ *
+ * <p>Normalization applies uniformly to all decision types (experiment, feature test,
+ * rollout, holdout). It must not drop, defer, or fail event dispatch, and it must not
+ * emit any log or warning on the normalization path.
+ */
+final class EventIdNormalizer {
+
+    private EventIdNormalizer() {
+        // Utility class — not instantiable.
+    }
+
+    /**
+     * @return {@code true} iff {@code value} is non-null and has length &ge; 1.
+     *         Character content is not validated — any non-empty string is accepted.
+     *         Used to validate {@code campaign_id} and impression {@code entity_id}.
+     */
+    static boolean isNonEmptyString(String value) {
+        return value != null && !value.isEmpty();
+    }
+
+    /**
+     * @return {@code true} iff {@code value} is non-null and consists entirely of decimal digits.
+     *         Empty strings, whitespace, negatives, decimals, and exponents are all invalid.
+     *         Used to validate {@code variation_id} per the strict numeric-string contract.
+     */
+    static boolean isNumericString(String value) {
+        if (value == null) {
+            return false;
+        }
+        int length = value.length();
+        if (length == 0) {
+            return false;
+        }
+        for (int i = 0; i < length; i++) {
+            char c = value.charAt(i);
+            if (c < '0' || c > '9') {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Normalize a {@code campaign_id} or impression {@code entity_id}.
+     *
+     * <p>Any non-empty string is accepted as-is (IDs may be opaque, e.g.
+     * {@code "default-12345"}, {@code "layer_abc"}). The fallback to
+     * {@code experiment_id} fires ONLY when {@code campaignId} is {@code null} or
+     * the empty string {@code ""}.
+     *
+     * @param campaignId the candidate campaign_id (may be null or empty)
+     * @param experimentId fallback experiment_id (returned as-is; not re-validated)
+     * @return {@code campaignId} when it is a non-empty string of any content,
+     *         otherwise {@code experimentId} (which may itself be {@code null}).
+     */
+    static String normalizeCampaignId(String campaignId, String experimentId) {
+        if (isNonEmptyString(campaignId)) {
+            return campaignId;
+        }
+        return experimentId;
+    }
+
+    /**
+     * Normalize a {@code variation_id}. {@code variation_id} retains the stricter
+     * contract: must be a non-empty decimal-digit string. Anything else (null,
+     * empty, whitespace, or non-numeric) is replaced with {@code null}.
+     *
+     * @param variationId the candidate variation_id (may be null, empty, or non-numeric)
+     * @return {@code variationId} when it is a non-empty numeric string, otherwise {@code null}.
+     */
+    static String normalizeVariationId(String variationId) {
+        if (isNumericString(variationId)) {
+            return variationId;
+        }
+        return null;
+    }
+}

core-api/src/main/java/com/optimizely/ab/event/internal/payload/Decision.java

@@ -27,6 +27,7 @@ public class Decision {
     @JsonInclude(JsonInclude.Include.ALWAYS)
     @JsonProperty("experiment_id")
     String experimentId;
+    @JsonInclude(JsonInclude.Include.ALWAYS)
     @JsonProperty("variation_id")
     String variationId;
     @JsonProperty("is_campaign_holdback")

core-api/src/test/java/com/optimizely/ab/OptimizelyTest.java

@@ -1,5 +1,5 @@
 /****************************************************************************
- * Copyright 2016-2023, Optimizely, Inc. and contributors                   *
+ * Copyright 2016-2023, 2026, Optimizely, Inc. and contributors             *
  *                                                                          *
  * Licensed under the Apache License, Version 2.0 (the "License");          *
  * you may not use this file except in compliance with the License.         *
@@ -618,7 +618,7 @@ public void isFeatureEnabledWithExperimentKeyForced() throws Exception {
         assertTrue(optimizely.setForcedVariation(activatedExperiment.getKey(), testUserId, null));
         assertNull(optimizely.getForcedVariation(activatedExperiment.getKey(), testUserId));
         assertFalse(optimizely.isFeatureEnabled(FEATURE_FLAG_MULTI_VARIATE_FEATURE.getKey(), testUserId));
-        eventHandler.expectImpression(null, "", testUserId);
+        eventHandler.expectImpression(null, null, testUserId);
     }
 
     /**
@@ -1810,13 +1810,13 @@ public void getEnabledFeaturesWithListenerMultipleFeatureEnabled() throws Except
         List<String> featureFlags = optimizely.getEnabledFeatures(testUserId, Collections.emptyMap());
         assertEquals(2, featureFlags.size());
 
-        eventHandler.expectImpression(null, "", testUserId);
-        eventHandler.expectImpression(null, "", testUserId);
+        eventHandler.expectImpression(null, null, testUserId);
+        eventHandler.expectImpression(null, null, testUserId);
         eventHandler.expectImpression("3794675122", "589640735", testUserId);
-        eventHandler.expectImpression(null, "", testUserId);
-        eventHandler.expectImpression(null, "", testUserId);
-        eventHandler.expectImpression(null, "", testUserId);
-        eventHandler.expectImpression(null, "", testUserId);
+        eventHandler.expectImpression(null, null, testUserId);
+        eventHandler.expectImpression(null, null, testUserId);
+        eventHandler.expectImpression(null, null, testUserId);
+        eventHandler.expectImpression(null, null, testUserId);
         eventHandler.expectImpression("1786133852", "1619235542", testUserId);
 
         // Verify that listener being called
@@ -1853,14 +1853,14 @@ public void getEnabledFeaturesWithNoFeatureEnabled() throws Exception {
         // Verify that listener not being called
         assertFalse(isListenerCalled);
 
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
 
         assertTrue(optimizely.notificationCenter.removeNotificationListener(notificationId));
     }
@@ -2013,7 +2013,7 @@ public void isFeatureEnabledWithListenerUserNotInExperimentAndNotInRollOut() thr
             "Feature \"" + validFeatureKey +
                 "\" is enabled for user \"" + genericUserId + "\"? false"
         );
-        eventHandler.expectImpression(null, "", genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
 
         // Verify that listener being called
         assertTrue(isListenerCalled);
@@ -3339,7 +3339,7 @@ public void isFeatureEnabledReturnsFalseWhenUserIsNotBucketedIntoAnyVariation()
             "Feature \"" + validFeatureKey +
                 "\" is enabled for user \"" + genericUserId + "\"? false"
         );
-        eventHandler.expectImpression(null, "", genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
 
         verify(mockDecisionService).getVariationForFeature(
             eq(FEATURE_FLAG_MULTI_VARIATE_FEATURE),
@@ -3384,7 +3384,7 @@ public void isFeatureEnabledReturnsTrueButDoesNotSendWhenUserIsBucketedIntoVaria
             "Feature \"" + validFeatureKey +
                 "\" is enabled for user \"" + genericUserId + "\"? true"
         );
-        eventHandler.expectImpression("3421010877", "variationId", genericUserId);
+        eventHandler.expectImpression("3421010877", null, genericUserId);
 
         verify(mockDecisionService).getVariationForFeature(
             eq(FEATURE_FLAG_MULTI_VARIATE_FEATURE),
@@ -3456,7 +3456,7 @@ public void isFeatureEnabledTrueWhenFeatureEnabledOfVariationIsTrue() throws Exc
         );
 
         assertTrue(optimizely.isFeatureEnabled(validFeatureKey, genericUserId));
-        eventHandler.expectImpression("3421010877", "variationId", genericUserId);
+        eventHandler.expectImpression("3421010877", null, genericUserId);
 
     }
 
@@ -3485,7 +3485,7 @@ public void isFeatureEnabledFalseWhenFeatureEnabledOfVariationIsFalse() throws E
         );
 
         assertFalse(spyOptimizely.isFeatureEnabled(FEATURE_MULTI_VARIATE_FEATURE_KEY, genericUserId));
-        eventHandler.expectImpression("3421010877", "variationId", genericUserId);
+        eventHandler.expectImpression("3421010877", null, genericUserId);
 
     }
 
@@ -3582,10 +3582,10 @@ public void getEnabledFeatureWithValidUserId() throws Exception {
         List<String> featureFlags = optimizely.getEnabledFeatures(genericUserId, Collections.emptyMap());
         assertFalse(featureFlags.isEmpty());
 
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
         eventHandler.expectImpression("3794675122", "589640735", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
         eventHandler.expectImpression("1785077004", "1566407342", genericUserId);
         eventHandler.expectImpression("828245624", "3137445031", genericUserId);
         eventHandler.expectImpression("828245624", "3137445031", genericUserId);
@@ -3606,10 +3606,10 @@ public void getEnabledFeatureWithEmptyUserId() throws Exception {
         List<String> featureFlags = optimizely.getEnabledFeatures("", Collections.emptyMap());
         assertFalse(featureFlags.isEmpty());
 
-        eventHandler.expectImpression(null, "", "");
-        eventHandler.expectImpression(null, "", "");
+        eventHandler.expectImpression(null, null, "");
+        eventHandler.expectImpression(null, null, "");
         eventHandler.expectImpression("3794675122", "589640735", "");
-        eventHandler.expectImpression(null, "", "");
+        eventHandler.expectImpression(null, null, "");
         eventHandler.expectImpression("1785077004", "1566407342", "");
         eventHandler.expectImpression("828245624", "3137445031", "");
         eventHandler.expectImpression("828245624", "3137445031", "");
@@ -3660,14 +3660,14 @@ public void getEnabledFeatureWithMockDecisionService() throws Exception {
         List<String> featureFlags = optimizely.getEnabledFeatures(genericUserId, Collections.emptyMap());
         assertTrue(featureFlags.isEmpty());
 
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
-        eventHandler.expectImpression(null, "", genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
+        eventHandler.expectImpression(null, null, genericUserId);
     }
 
     /**

core-api/src/test/java/com/optimizely/ab/OptimizelyUserContextTest.java

@@ -1,6 +1,6 @@
 /**
  *
- *    Copyright 2021-2024, Optimizely and contributors
+ *    Copyright 2021-2024, 2026, Optimizely and contributors
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -267,7 +267,7 @@ public void decide_nullVariation() {
             .setVariationKey("")
             .setEnabled(false)
             .build();
-        eventHandler.expectImpression(null, "", userId, Collections.emptyMap(), metadata);
+        eventHandler.expectImpression(null, null, userId, Collections.emptyMap(), metadata);
     }
 
     // decideAll
@@ -639,7 +639,7 @@ public void decide_sendEvent_rollout_withSendFlagDecisionsOn() {
         user.decide(flagKey);
         assertTrue(isListenerCalled);
 
-        eventHandler.expectImpression(null, "", userId, attributes);
+        eventHandler.expectImpression(null, null, userId, attributes);
     }
 
     @Test
@@ -2102,6 +2102,7 @@ public void decisionNotification_with_holdout() throws Exception {
         String variationKey = "ho_off_key";            // holdout (off) variation key
         String experimentId = "10075323428";           // holdout experiment id in holdouts-project-config.json
         String variationId = "$opt_dummy_variation_id";// dummy variation id used for holdout impressions
+        String expectedDispatchedVariationId = null;
         String expectedReason = "User (" + userId + ") is in variation (" + variationKey + ") of holdout (" + ruleKey + ").";
 
         Map<String, Object> attrs = new HashMap<>();
@@ -2153,7 +2154,7 @@ public void decisionNotification_with_holdout() throws Exception {
             .setVariationKey(variationKey)
             .setEnabled(false)
             .build();
-        eventHandler.expectImpression(experimentId, variationId, userId, Collections.singletonMap("nationality", "English"), metadata);
+        eventHandler.expectImpression(experimentId, expectedDispatchedVariationId, userId, Collections.singletonMap("nationality", "English"), metadata);
 
         // Log expectation (reuse existing pattern)
         logbackVerifier.expectMessage(Level.INFO, expectedReason);
@@ -2177,6 +2178,7 @@ public void decide_for_keys_with_holdout() throws Exception {
 
         String holdoutExperimentId = "10075323428"; // basic_holdout id
         String variationId = "$opt_dummy_variation_id";
+        String expectedDispatchedVariationId = null;
         String variationKey = "ho_off_key";
         String expectedReason = "User (" + userId + ") is in variation (" + variationKey + ") of holdout (basic_holdout).";
 
@@ -2195,7 +2197,7 @@ public void decide_for_keys_with_holdout() throws Exception {
                 .setEnabled(false)
                 .build();
             // attributes map expected empty (reserved $opt_ attribute filtered out)
-            eventHandler.expectImpression(holdoutExperimentId, variationId, userId, Collections.emptyMap(), metadata);
+            eventHandler.expectImpression(holdoutExperimentId, expectedDispatchedVariationId, userId, Collections.emptyMap(), metadata);
         }
 
         // At least one log message confirming holdout membership