Update collectFields: no longer throws errors that validation should catch

Author: mjmahone

src/execution/__tests__/variables-test.ts

@@ -1054,16 +1054,6 @@ describe('Execute: Handles inputs', () => {
         data: {
           fieldWithNullableStringInput: null,
         },
-        errors: [
-          {
-            message:
-              'Fragment argument "$value" on fragment "a" is required but not provided.',
-            locations: [
-              { line: 3, column: 11 },
-              { line: 6, column: 20 },
-            ],
-          },
-        ],
       });
     });
 
@@ -1115,16 +1105,6 @@ describe('Execute: Handles inputs', () => {
         data: {
           fieldWithNullableStringInput: 'null',
         },
-        errors: [
-          {
-            message:
-              'Fragment argument "$value" on fragment "a" is non-null, but null was provided.',
-            locations: [
-              { line: 3, column: 16 },
-              { line: 6, column: 20 },
-            ],
-          },
-        ],
       });
     });
 

src/execution/collectFields.ts

@@ -1,11 +1,13 @@
 import type { ObjMap } from '../jsutils/ObjMap';
 
 import type {
-  SelectionSetNode,
+  ArgumentNode,
   FieldNode,
   FragmentSpreadNode,
   InlineFragmentNode,
   FragmentDefinitionNode,
+  SelectionSetNode,
+  ValueNode,
 } from '../language/ast';
 import { Kind } from '../language/kinds';
 
@@ -19,6 +21,8 @@ import { isAbstractType } from '../type/definition';
 
 import { typeFromAST } from '../utilities/typeFromAST';
 
+import { visit } from '../language/visitor';
+
 import { getDirectiveValues } from './values';
 
 /**
@@ -89,12 +93,14 @@ export function collectFields(
         ) {
           continue;
         }
+        const selectionSetWithArgumentsApplied =
+          selectionSetWithFragmentArgumentsApplied(fragment, selection);
         collectFields(
           schema,
           fragments,
           variableValues,
           runtimeType,
-          fragment.selectionSet,
+          selectionSetWithArgumentsApplied,
           fields,
           visitedFragmentNames,
         );
@@ -157,3 +163,44 @@ function doesFragmentConditionMatch(
 function getFieldEntryKey(node: FieldNode): string {
   return node.alias ? node.alias.value : node.name.value;
 }
+
+/**
+ *
+ * When a fragment spread is provided with arguments,
+ * visit that fragment's definition and replace those arguments'
+ * variable usages with the provided argument value.
+ */
+function selectionSetWithFragmentArgumentsApplied(
+  fragment: FragmentDefinitionNode,
+  fragmentSpread: FragmentSpreadNode,
+): SelectionSetNode {
+  const variableDefinitions = fragment.variableDefinitions;
+  if (!variableDefinitions) {
+    return fragment.selectionSet;
+  }
+
+  const providedArguments: Map<string, ArgumentNode> = new Map();
+  if (fragmentSpread.arguments) {
+    for (const argument of fragmentSpread.arguments) {
+      providedArguments.set(argument.name.value, argument);
+    }
+  }
+
+  const fragmentVariableValues: Map<string, ValueNode> = new Map();
+  for (const variableDef of variableDefinitions) {
+    const variableName = variableDef.variable.name.value;
+    const providedArg = providedArguments.get(variableName);
+    if (providedArg) {
+      fragmentVariableValues.set(variableName, providedArg.value);
+    } else if (variableDef.defaultValue) {
+      fragmentVariableValues.set(variableName, variableDef.defaultValue);
+    }
+    // Otherwise just preserve the variable as-is: it will be treated as unset by the executor.
+  }
+
+  return visit(fragment.selectionSet, {
+    Variable(node) {
+      return fragmentVariableValues.get(node.name.value);
+    },
+  });
+}

src/execution/execute.ts

@@ -22,11 +22,8 @@ import type {
   OperationDefinitionNode,
   FieldNode,
   FragmentDefinitionNode,
-  ArgumentNode,
-  ValueNode,
 } from '../language/ast';
 import { Kind } from '../language/kinds';
-import { visit } from '../language/visitor';
 
 import type { GraphQLSchema } from '../type/schema';
 import type {