fix(gofeatureflag): fix unreachable code when flag not found (#1679)

Signed-off-by: Thomas Poignant <thomas.poignant@gofeatureflag.org>

Author: thomaspoignant

providers/go-feature-flag/src/main/java/dev/openfeature/contrib/providers/gofeatureflag/service/EvaluationService.java

@@ -68,6 +68,12 @@ public <T> ProviderEvaluation<T> getEvaluation(
 
         val goffResp = evaluator.evaluate(flagKey, defaultValue, evaluationContext);
 
+        // Check for FLAG_NOT_FOUND error first, before general error handling
+        if (goffResp.getErrorCode() != null
+                && ErrorCode.FLAG_NOT_FOUND.name().equalsIgnoreCase(goffResp.getErrorCode())) {
+            throw new FlagNotFoundError("Flag " + flagKey + " was not found in your configuration");
+        }
+
         // If we have an error code, we return the error directly.
         if (goffResp.getErrorCode() != null && !goffResp.getErrorCode().isEmpty()) {
             return ProviderEvaluation.<T>builder()
@@ -88,10 +94,6 @@ public <T> ProviderEvaluation<T> getEvaluation(
                     .build();
         }
 
-        if (ErrorCode.FLAG_NOT_FOUND.name().equalsIgnoreCase(goffResp.getErrorCode())) {
-            throw new FlagNotFoundError("Flag " + flagKey + " was not found in your configuration");
-        }
-
         // Convert the value received from the API.
         T flagValue = convertValue(goffResp.getValue(), expectedType);
 

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

@@ -0,0 +1,101 @@
+package dev.openfeature.contrib.providers.gofeatureflag.service;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import dev.openfeature.contrib.providers.gofeatureflag.bean.GoFeatureFlagResponse;
+import dev.openfeature.contrib.providers.gofeatureflag.evaluator.IEvaluator;
+import dev.openfeature.sdk.ErrorCode;
+import dev.openfeature.sdk.EvaluationContext;
+import dev.openfeature.sdk.ImmutableContext;
+import dev.openfeature.sdk.ProviderEvaluation;
+import dev.openfeature.sdk.Reason;
+import dev.openfeature.sdk.exceptions.FlagNotFoundError;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+@DisplayName("EvaluationService tests")
+class EvaluationServiceTest {
+    private IEvaluator mockEvaluator;
+    private EvaluationService evaluationService;
+    private EvaluationContext evaluationContext;
+
+    @BeforeEach
+    void setUp() {
+        mockEvaluator = mock(IEvaluator.class);
+        evaluationService = new EvaluationService(mockEvaluator);
+        evaluationContext = new ImmutableContext("test-targeting-key");
+    }
+
+    @DisplayName("Should throw FlagNotFoundError when flag is not found")
+    @Test
+    void shouldThrowFlagNotFoundErrorWhenFlagIsNotFound() {
+        // Given: evaluator returns a response with FLAG_NOT_FOUND error code
+        GoFeatureFlagResponse response = new GoFeatureFlagResponse();
+        response.setErrorCode(ErrorCode.FLAG_NOT_FOUND.name());
+        response.setErrorDetails("Flag test-flag was not found in your configuration");
+        response.setValue(false);
+
+        when(mockEvaluator.evaluate(anyString(), any(), any(EvaluationContext.class)))
+                .thenReturn(response);
+
+        // When/Then: getEvaluation should throw FlagNotFoundError
+        FlagNotFoundError exception = assertThrows(
+                FlagNotFoundError.class,
+                () -> evaluationService.getEvaluation("test-flag", false, evaluationContext, Boolean.class));
+
+        assertEquals("Flag test-flag was not found in your configuration", exception.getMessage());
+    }
+
+    @DisplayName("Should return error response for other error codes")
+    @Test
+    void shouldReturnErrorResponseForOtherErrorCodes() {
+        // Given: evaluator returns a response with a different error code
+        GoFeatureFlagResponse response = new GoFeatureFlagResponse();
+        response.setErrorCode(ErrorCode.GENERAL.name());
+        response.setErrorDetails("Some other error occurred");
+        response.setValue(false);
+
+        when(mockEvaluator.evaluate(anyString(), any(), any(EvaluationContext.class)))
+                .thenReturn(response);
+
+        // When: getEvaluation is called
+        ProviderEvaluation<Boolean> result =
+                evaluationService.getEvaluation("test-flag", false, evaluationContext, Boolean.class);
+
+        // Then: should return error response, not throw exception
+        assertEquals(ErrorCode.GENERAL, result.getErrorCode());
+        assertEquals("Some other error occurred", result.getErrorMessage());
+        assertEquals(Reason.ERROR.name(), result.getReason());
+        assertEquals(false, result.getValue());
+    }
+
+    @DisplayName("Should handle successful evaluation")
+    @Test
+    void shouldHandleSuccessfulEvaluation() {
+        // Given: evaluator returns a successful response
+        GoFeatureFlagResponse response = new GoFeatureFlagResponse();
+        response.setValue(true);
+        response.setReason(Reason.TARGETING_MATCH.name());
+        response.setVariationType("enabled");
+        response.setErrorCode(null);
+
+        when(mockEvaluator.evaluate(anyString(), any(), any(EvaluationContext.class)))
+                .thenReturn(response);
+
+        // When: getEvaluation is called
+        ProviderEvaluation<Boolean> result =
+                evaluationService.getEvaluation("test-flag", false, evaluationContext, Boolean.class);
+
+        // Then: should return successful evaluation
+        assertEquals(true, result.getValue());
+        assertEquals(Reason.TARGETING_MATCH.name(), result.getReason());
+        assertEquals("enabled", result.getVariant());
+        assertEquals(null, result.getErrorCode());
+    }
+}