Add key fields to selections even when they're already selected with an alias

libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/internal/addRequiredFields.kt

@@ -94,7 +94,7 @@ private fun List<GQLSelection>.addRequiredFields(
     requiredFieldNames.add("__typename")
   }
 
-  val fieldNames = parentFields + selectionSet.filterIsInstance<GQLField>().map { it.name }.toSet()
+  val fieldNames = parentFields + selectionSet.filterIsInstance<GQLField>().map { it.alias ?: it.name }.toSet()
 
   var newSelections = selectionSet.map {
     when (it) {

libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/internal/checkKeyFields.kt

@@ -39,7 +39,11 @@ internal fun checkKeyFields(
     schema: Schema,
     allFragmentDefinitions: Map<String, GQLFragmentDefinition>,
 ) {
-  CheckKeyFieldsScope(schema, allFragmentDefinitions).checkField("Fragment(${fragmentDefinition.name})", fragmentDefinition.selections, fragmentDefinition.typeCondition.name)
+  CheckKeyFieldsScope(schema, allFragmentDefinitions).checkField(
+      "Fragment(${fragmentDefinition.name})",
+      fragmentDefinition.selections,
+      fragmentDefinition.typeCondition.name
+  )
 }
 
 private fun CheckKeyFieldsScope.checkField(
@@ -61,9 +65,9 @@ private fun CheckKeyFieldsScope.checkFieldSet(path: String, selections: List<GQL
 
   if (implementedTypes.contains(parentType)) {
     // only check types that are actually possible
-    val fieldNames = mergedFields.map { it.first().field }
-        .filter { it.alias == null }
-        .map { it.name }.toSet()
+    val fieldNames = mergedFields
+        .flatMap { it.filter { it.field.alias == null }.map { it.field.name } }
+        .toSet()
     val keyFieldNames = keyFields(possibleType)
 
     val missingFieldNames = keyFieldNames.subtract(fieldNames)
@@ -101,13 +105,15 @@ private fun CheckKeyFieldsScope.collectFields(
 
         listOf(FieldWithParent(it, parentType))
       }
+
       is GQLInlineFragment -> {
         if (it.directives.hasCondition()) {
           return@flatMap emptyList()
         }
 
         collectFields(it.selections, it.typeCondition?.name ?: parentType, implementedTypes)
       }
+
       is GQLFragmentSpread -> {
         if (it.directives.hasCondition()) {
           return@flatMap emptyList()

libraries/apollo-compiler/src/test/graphql/com/example/typepolicy/TestOperation.graphql

@@ -0,0 +1,15 @@
+query GetA {
+  a {
+    ...AFragment1
+  }
+}
+
+fragment AFragment1 on A {
+  foo
+  ...AFragment2
+}
+
+fragment AFragment2 on A {
+  bar
+  myId: id
+}