gnhf #2: Eliminated Builder allocation overhead in ExecutionStepInfo creation (~66K/op), MergedSelectionSet construction (~5.5K/op), and optimized Async.Many.await() for the fully-materialized case by using CompletableFuture.completedFuture() instead of new+complete.

dondonz · dondonz · commit 477967709cf1 · 2026-04-04T15:19:34.000+11:00
diff --git a/src/main/java/graphql/execution/Async.java b/src/main/java/graphql/execution/Async.java
@@ -197,10 +197,11 @@ public void addObject(Object object) {
         public CompletableFuture<List<T>> await() {
             commonSizeAssert();
 
-            CompletableFuture<List<T>> overallResult = new CompletableFuture<>();
             if (cfCount == 0) {
-                overallResult.complete(materialisedList(array));
-            } else {
+                return CompletableFuture.completedFuture(materialisedList(array));
+            }
+            CompletableFuture<List<T>> overallResult = new CompletableFuture<>();
+            {
                 CompletableFuture<T>[] cfsArr = copyOnlyCFsToArray();
                 CompletableFuture.allOf(cfsArr)
                         .whenComplete((ignored, exception) -> {
diff --git a/src/main/java/graphql/execution/ExecutionStepInfo.java b/src/main/java/graphql/execution/ExecutionStepInfo.java
@@ -274,6 +274,20 @@ public static ExecutionStepInfo.Builder newExecutionStepInfo() {
         return new Builder();
     }
 
+    /**
+     * Package-private direct construction that bypasses the Builder, avoiding 2 allocations in the hot path.
+     */
+    static ExecutionStepInfo newExecutionStepInfoDirect(
+            GraphQLOutputType type,
+            ResultPath path,
+            ExecutionStepInfo parent,
+            MergedField field,
+            GraphQLFieldDefinition fieldDefinition,
+            GraphQLObjectType fieldContainer,
+            Supplier<ImmutableMapWithNullValues<String, Object>> arguments) {
+        return new ExecutionStepInfo(type, path, parent, field, fieldDefinition, fieldContainer, arguments);
+    }
+
     public static ExecutionStepInfo.Builder newExecutionStepInfo(ExecutionStepInfo existing) {
         return new Builder(existing);
     }
diff --git a/src/main/java/graphql/execution/ExecutionStepInfoFactory.java b/src/main/java/graphql/execution/ExecutionStepInfoFactory.java
@@ -18,7 +18,6 @@
 import java.util.Map;
 import java.util.function.Supplier;
 
-import static graphql.execution.ExecutionStepInfo.newExecutionStepInfo;
 
 @Internal
 @NullMarked
@@ -57,15 +56,15 @@ public ExecutionStepInfo createExecutionStepInfo(ExecutionContext executionConte
         }
 
 
-        return newExecutionStepInfo()
-                .type(fieldType)
-                .fieldDefinition(fieldDefinition)
-                .fieldContainer(fieldContainer)
-                .field(field)
-                .path(parameters.getPath())
-                .parentInfo(parentStepInfo)
-                .arguments(argumentValues)
-                .build();
+        return ExecutionStepInfo.newExecutionStepInfoDirect(
+                fieldType,
+                parameters.getPath(),
+                parentStepInfo,
+                field,
+                fieldDefinition,
+                fieldContainer,
+                argumentValues
+        );
     }
 
     @NonNull
diff --git a/src/main/java/graphql/execution/FieldCollector.java b/src/main/java/graphql/execution/FieldCollector.java
@@ -22,7 +22,6 @@
 import java.util.Map;
 import java.util.Set;
 
-import static graphql.execution.MergedSelectionSet.newMergedSelectionSet;
 import static graphql.execution.TypeFromAST.getTypeFromAST;
 
 /**
@@ -46,7 +45,7 @@ public MergedSelectionSet collectFields(FieldCollectorParameters parameters, Mer
                 this.collectFields(parameters, field.getSelectionSet(), visitedFragments, subFields, null, incrementalSupport);
             }
         });
-        return newMergedSelectionSet().subFields(subFields).build();
+        return MergedSelectionSet.newMergedSelectionSetDirect(subFields);
     }
 
     /**
@@ -65,7 +64,7 @@ public MergedSelectionSet collectFields(FieldCollectorParameters parameters, Sel
         Map<String, MergedField> subFields = new LinkedHashMap<>();
         Set<String> visitedFragments = new LinkedHashSet<>();
         this.collectFields(parameters, selectionSet, visitedFragments, subFields, null, incrementalSupport);
-        return newMergedSelectionSet().subFields(subFields).build();
+        return MergedSelectionSet.newMergedSelectionSetDirect(subFields);
     }
 
 
diff --git a/src/main/java/graphql/execution/MergedSelectionSet.java b/src/main/java/graphql/execution/MergedSelectionSet.java
@@ -52,6 +52,13 @@ public static Builder newMergedSelectionSet() {
         return new Builder();
     }
 
+    /**
+     * Package-private direct construction that bypasses the Builder, avoiding 1 allocation in the hot path.
+     */
+    static MergedSelectionSet newMergedSelectionSetDirect(Map<String, MergedField> subFields) {
+        return new MergedSelectionSet(subFields);
+    }
+
     public static class Builder {
 
         private Map<String, MergedField> subFields;

Original file line number	Diff line number	Diff line change
`@@ -22,7 +22,6 @@`
`22`	`22`	`import java.util.Map;`
`23`	`23`	`import java.util.Set;`
`24`	`24`
`25`		`-import static graphql.execution.MergedSelectionSet.newMergedSelectionSet;`
`26`	`25`	`import static graphql.execution.TypeFromAST.getTypeFromAST;`
`27`	`26`
`28`	`27`	`/**`
`@@ -46,7 +45,7 @@ public MergedSelectionSet collectFields(FieldCollectorParameters parameters, Mer`
`46`	`45`	`this.collectFields(parameters, field.getSelectionSet(), visitedFragments, subFields, null, incrementalSupport);`
`47`	`46`	`}`
`48`	`47`	`});`
`49`		`- return newMergedSelectionSet().subFields(subFields).build();`
	`48`	`+ return MergedSelectionSet.newMergedSelectionSetDirect(subFields);`
`50`	`49`	`}`
`51`	`50`
`52`	`51`	`/**`
`@@ -65,7 +64,7 @@ public MergedSelectionSet collectFields(FieldCollectorParameters parameters, Sel`
`65`	`64`	`Map<String, MergedField> subFields = new LinkedHashMap<>();`
`66`	`65`	`Set<String> visitedFragments = new LinkedHashSet<>();`
`67`	`66`	`this.collectFields(parameters, selectionSet, visitedFragments, subFields, null, incrementalSupport);`
`68`		`- return newMergedSelectionSet().subFields(subFields).build();`
	`67`	`+ return MergedSelectionSet.newMergedSelectionSetDirect(subFields);`
`69`	`68`	`}`
`70`	`69`
`71`	`70`