Merge pull request #1202 from Netflix/feature/duplicate-fetcher-valid…

…ation Add duplicate data fetcher validation
Netflix · Aug 26, 2022 · eb6493e · eb6493e
2 parents b7ca0d3 + 8ef30b0
commit eb6493e
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diff --git a/graphql-dgs/src/main/kotlin/com/netflix/graphql/dgs/internal/DgsSchemaProvider.kt b/graphql-dgs/src/main/kotlin/com/netflix/graphql/dgs/internal/DgsSchemaProvider.kt
@@ -289,6 +289,11 @@ class DgsSchemaProvider(
         val field = dgsDataAnnotation.getString("field").ifEmpty { method.name }
         val parentType = dgsDataAnnotation.getString("parentType")
 
+        if (dataFetchers.any { it.parentType == parentType && it.field == field }) {
+            logger.error("Duplicate data fetchers registered for $parentType.$field")
+            throw InvalidDgsConfigurationException("Duplicate data fetchers registered for $parentType.$field")
+        }
+
         dataFetchers.add(DataFetcherReference(dgsComponent, method, mergedAnnotations, parentType, field))
 
         val enableInstrumentation =

diff --git a/graphql-dgs/src/test/kotlin/com/netflix/graphql/dgs/DgsSchemaProviderTest.kt b/graphql-dgs/src/test/kotlin/com/netflix/graphql/dgs/DgsSchemaProviderTest.kt
@@ -16,6 +16,7 @@
 
 package com.netflix.graphql.dgs
 
+import com.netflix.graphql.dgs.exceptions.InvalidDgsConfigurationException
 import com.netflix.graphql.dgs.exceptions.InvalidTypeResolverException
 import com.netflix.graphql.dgs.exceptions.NoSchemaFoundException
 import com.netflix.graphql.dgs.internal.DefaultInputObjectMapper
@@ -229,6 +230,27 @@ internal class DgsSchemaProviderTest {
         verifyComponents()
     }
 
+    @Test
+    fun withDuplicateFetchers() {
+        val fetcher = object : Any() {
+            @DgsData(parentType = "Query", field = "hello")
+            fun fetcher1(): String {
+                return "fetcher1"
+            }
+            @DgsData(parentType = "Query", field = "hello")
+            fun fetcher2(): String {
+                return "fetcher2"
+            }
+        }
+
+        withComponents("helloFetcher" to fetcher)
+
+        val error: InvalidDgsConfigurationException = assertThrows {
+            GraphQL.newGraphQL(schemaProvider().schema()).build()
+        }
+        assertThat(error.message).isEqualTo("Duplicate data fetchers registered for Query.hello")
+    }
+
     open class BaseClassFetcher {
         @DgsData(parentType = "Query", field = "hello")
         private fun someFetcher(): String {