fix(gofeatureflag): Fix NPE when error code is not set in the API response (#855)

Signed-off-by: Thomas Poignant <[email protected]>

Author: thomaspoignant

providers/go-feature-flag/src/main/java/dev/openfeature/contrib/providers/gofeatureflag/controller/GoFeatureFlagController.java

@@ -142,7 +142,7 @@ public <T> EvaluationResponse<T> evaluateFlag(
                             requestMapper.writeValueAsBytes(goffRequest),
                             MediaType.get("application/json; charset=utf-8")));
 
-            if (this.apiKey != null && !"".equals(this.apiKey)) {
+            if (this.apiKey != null && !this.apiKey.isEmpty()) {
                 reqBuilder.addHeader(HttpHeaders.AUTHORIZATION, BEARER_TOKEN + this.apiKey);
             }
 
@@ -299,6 +299,10 @@ public ConfigurationChange configurationHasChanged() throws GoFeatureFlagExcepti
      * @return an item from the enum
      */
     private ErrorCode mapErrorCode(String errorCode) {
+        if (errorCode == null || errorCode.isEmpty()) {
+            return null;
+        }
+        
         try {
             return ErrorCode.valueOf(errorCode);
         } catch (IllegalArgumentException e) {

providers/go-feature-flag/src/test/java/dev/openfeature/contrib/providers/gofeatureflag/GoFeatureFlagProviderTest.java

@@ -316,6 +316,24 @@ void should_resolve_a_valid_boolean_flag_with_TARGETING_MATCH_reason() {
         assertEquals(want, got);
     }
 
+    @SneakyThrows
+    @Test
+    void should_resolve_a_valid_boolean_flag_with_TARGETING_MATCH_reason_without_error_code_in_payload() {
+        GoFeatureFlagProvider g = new GoFeatureFlagProvider(GoFeatureFlagProviderOptions.builder().endpoint(this.baseUrl.toString()).timeout(1000).build());
+        String providerName = this.testName;
+        OpenFeatureAPI.getInstance().setProviderAndWait(providerName, g);
+        Client client = OpenFeatureAPI.getInstance().getClient(providerName);
+        FlagEvaluationDetails<Boolean> got = client.getBooleanDetails("bool_targeting_match_no_error_code", false, this.evaluationContext);
+        FlagEvaluationDetails<Boolean> want = FlagEvaluationDetails.<Boolean>builder()
+                .value(true)
+                .variant("True")
+                .flagKey("bool_targeting_match_no_error_code")
+                .reason(Reason.TARGETING_MATCH.name())
+                .flagMetadata(defaultMetadata)
+                .build();
+        assertEquals(want, got);
+    }
+
     @SneakyThrows
     @Test
     void should_resolve_a_valid_boolean_flag_with_TARGETING_MATCH_reason_cache_disabled() {

providers/go-feature-flag/src/test/resources/mock_responses/bool_targeting_match_no_error_code.json

@@ -0,0 +1,13 @@
+{
+  "trackEvents": true,
+  "variationType": "True",
+  "failed": false,
+  "version": 0,
+  "reason": "TARGETING_MATCH",
+  "value": true,
+  "cacheable": true,
+  "metadata": {
+    "pr_link": "https://github.com/thomaspoignant/go-feature-flag/pull/916",
+    "version": 1
+  }
+}