fix: invalid lookup for null context in field resolvers

demo/pkg/subgraphs/courses/generated/mapping.json

@@ -59,7 +59,8 @@
       "key": "id",
       "rpc": "LookupEmployeeById",
       "request": "LookupEmployeeByIdRequest",
-      "response": "LookupEmployeeByIdResponse"
+      "response": "LookupEmployeeByIdResponse",
+      "requiredFieldMappings": []
     }
   ],
   "typeFieldMappings": [

demo/pkg/subgraphs/projects/generated/mapping.json

@@ -150,39 +150,44 @@
       "key": "id",
       "rpc": "LookupProjectById",
       "request": "LookupProjectByIdRequest",
-      "response": "LookupProjectByIdResponse"
+      "response": "LookupProjectByIdResponse",
+      "requiredFieldMappings": []
     },
     {
       "typeName": "Milestone",
       "kind": "entity",
       "key": "id",
       "rpc": "LookupMilestoneById",
       "request": "LookupMilestoneByIdRequest",
-      "response": "LookupMilestoneByIdResponse"
+      "response": "LookupMilestoneByIdResponse",
+      "requiredFieldMappings": []
     },
     {
       "typeName": "Task",
       "kind": "entity",
       "key": "id",
       "rpc": "LookupTaskById",
       "request": "LookupTaskByIdRequest",
-      "response": "LookupTaskByIdResponse"
+      "response": "LookupTaskByIdResponse",
+      "requiredFieldMappings": []
     },
     {
       "typeName": "Employee",
       "kind": "entity",
       "key": "id",
       "rpc": "LookupEmployeeById",
       "request": "LookupEmployeeByIdRequest",
-      "response": "LookupEmployeeByIdResponse"
+      "response": "LookupEmployeeByIdResponse",
+      "requiredFieldMappings": []
     },
     {
       "typeName": "Product",
       "kind": "entity",
       "key": "upc",
       "rpc": "LookupProductByUpc",
       "request": "LookupProductByUpcRequest",
-      "response": "LookupProductByUpcResponse"
+      "response": "LookupProductByUpcResponse",
+      "requiredFieldMappings": []
     }
   ],
   "typeFieldMappings": [

demo/pkg/subgraphs/projects/generated/service.proto

@@ -764,7 +764,6 @@ message ResolveEmployeeAverageTaskCompletionDaysResponse {
 }
 
 message Project {
-  reserved 20 to 25;
   string id = 1;
   string name = 2;
   google.protobuf.StringValue description = 3;
@@ -787,7 +786,6 @@ message Project {
 }
 
 message Milestone {
-  reserved 12 to 13;
   string id = 1;
   string project_id = 2;
   string name = 3;
@@ -824,7 +822,6 @@ message Task {
 }
 
 message Employee {
-  reserved 8 to 9;
   int32 id = 1;
   ListOfProject projects = 2;
   repeated Task assigned_tasks = 3;

demo/pkg/subgraphs/projects/generated/service.proto.lock.json

@@ -351,13 +351,7 @@
         "resourceGroups": 16,
         "tasksByPhase": 17,
         "milestoneGroups": 18,
-        "priorityMatrix": 19,
-        "subProjects": 25,
-        "filteredTasks": 20,
-        "completionRate": 21,
-        "estimatedDaysRemaining": 22,
-        "criticalDeadline": 23,
-        "topPriorityItem": 24
+        "priorityMatrix": 19
       }
     },
     "Milestone": {
@@ -372,9 +366,7 @@
         "completionPercentage": 8,
         "dependencies": 9,
         "subtasks": 10,
-        "reviewers": 11,
-        "isAtRisk": 12,
-        "daysUntilDue": 13
+        "reviewers": 11
       }
     },
     "Task": {
@@ -395,10 +387,12 @@
         "subtasks": 14,
         "dependencies": 15,
         "attachmentUrls": 16,
-        "reviewerIds": 17,
-        "isBlocked": 18,
-        "totalEffort": 19
-      }
+        "reviewerIds": 17
+      },
+      "reservedNumbers": [
+        18,
+        19
+      ]
     },
     "Employee": {
       "fields": {
@@ -408,9 +402,7 @@
         "completedTasks": 4,
         "skills": 5,
         "certifications": 6,
-        "projectHistory": 7,
-        "currentWorkload": 8,
-        "averageTaskCompletionDays": 9
+        "projectHistory": 7
       }
     },
     "Product": {

router-tests/go.mod

@@ -27,7 +27,7 @@ require (
 	github.com/wundergraph/cosmo/demo/pkg/subgraphs/projects v0.0.0-20250715110703-10f2e5f9c79e
 	github.com/wundergraph/cosmo/router v0.0.0-20260213130455-6e3277e7b850
 	github.com/wundergraph/cosmo/router-plugin v0.0.0-20250808194725-de123ba1c65e
-	github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.257
+	github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.260
 	go.opentelemetry.io/otel v1.36.0
 	go.opentelemetry.io/otel/sdk v1.36.0
 	go.opentelemetry.io/otel/sdk/metric v1.36.0

router-tests/go.sum

@@ -356,8 +356,8 @@ github.com/wundergraph/astjson v1.1.0 h1:xORDosrZ87zQFJwNGe/HIHXqzpdHOFmqWgykCLV
 github.com/wundergraph/astjson v1.1.0/go.mod h1:h12D/dxxnedtLzsKyBLK7/Oe4TAoGpRVC9nDpDrZSWw=
 github.com/wundergraph/go-arena v1.1.0 h1:9+wSRkJAkA2vbYHp6s8tEGhPViRGQNGXqPHT0QzhdIc=
 github.com/wundergraph/go-arena v1.1.0/go.mod h1:ROOysEHWJjLQ8FSfNxZCziagb7Qw2nXY3/vgKRh7eWw=
-github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.257 h1:hGsaKXRkH3o8DkyizY48/wC1Q+NB1nfD9EKVA7Gc81Y=
-github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.257/go.mod h1:gfmmrPd2khZONmwYE8RIfnGjwIG+RqL52jYiBzcUST8=
+github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.260 h1:mVls0cWupP3ob16NwYiOP7jcNQnp89Abz4d3kz3ss7c=
+github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.260/go.mod h1:gfmmrPd2khZONmwYE8RIfnGjwIG+RqL52jYiBzcUST8=
 github.com/xrash/smetrics v0.0.0-20250705151800-55b8f293f342 h1:FnBeRrxr7OU4VvAzt5X7s6266i6cSVkkFPS0TuXWbIg=
 github.com/xrash/smetrics v0.0.0-20250705151800-55b8f293f342/go.mod h1:Ohn+xnUBiLI6FVj/9LpzZWtj1/D6lUovWYBkxHVV3aM=
 github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zIM+UJPGz4=

router-tests/grpc_subgraph_test.go

@@ -144,7 +144,7 @@ func TestGRPCSubgraph(t *testing.T) {
 				query: `
 				query {
 					nodesById(id: 1) {
-                        __typename
+			            __typename
 						... on Project {
 							id
 						}
@@ -264,6 +264,21 @@ func TestGRPCSubgraph(t *testing.T) {
 				query:    `{ project(id: 2) { id name urgent: topPriorityItem(category: "task") { __typename } nextDeadline: criticalDeadline(withinDays: 10000) { __typename } subsub: subProjects { id name status otherSubs: subProjects { id name } } } }`,
 				expected: `{"data":{"project":{"id":"2","name":"Microservices Revolution","urgent":{"__typename":"Task"},"nextDeadline":{"__typename":"Milestone"},"subsub":[{"id":"4","name":"DevOps Transformation","status":"PLANNING","otherSubs":[{"id":"1","name":"Cloud Migration Overhaul"}]},{"id":"5","name":"Security Overhaul","status":"ON_HOLD","otherSubs":[{"id":"2","name":"Microservices Revolution"}]}]}}}`,
 			},
+			{
+				name:     "query non-existent project returns null without invoking field resolvers",
+				query:    `{ project(id: 999) { id name topPriorityItem(category: "task") { __typename } criticalDeadline(withinDays: 10000) { __typename } } }`,
+				expected: `{"data":{"project":null}}`,
+			},
+			{
+				name:     "query non-existent project returns null without invoking recursive field resolvers",
+				query:    `{ project(id: 999) { id name subProjects { id name status subProjects { id name } } } }`,
+				expected: `{"data":{"project":null}}`,
+			},
+			{
+				name:     "query non-existent project returns null without invoking nested field resolvers with aliases",
+				query:    `{ project(id: 999) { id name urgent: topPriorityItem(category: "task") { __typename } nextDeadline: criticalDeadline(withinDays: 10000) { __typename } subsub: subProjects { id name status otherSubs: subProjects { id name } } } }`,
+				expected: `{"data":{"project":null}}`,
+			},
 		}
 		testenv.Run(t, &testenv.Config{
 			RouterConfigJSONTemplate: testenv.ConfigWithGRPCJSONTemplate,

router-tests/router_plugin_test.go

@@ -450,11 +450,26 @@ func TestRouterPluginRequests(t *testing.T) {
 			query:    `query { project(id:2) { id name urgent: topPriorityItem(category: "task") { __typename } nextDeadline: criticalDeadline(withinDays: 10000) { __typename } subsub: subProjects { id name status } } }`,
 			expected: `{"data":{"project":{"id":"2","name":"Microservices Revolution","urgent":{"__typename":"Task"},"nextDeadline":{"__typename":"Milestone"},"subsub":[{"id":"4","name":"DevOps Transformation","status":"PLANNING"},{"id":"5","name":"Security Overhaul","status":"ON_HOLD"}]}}}`,
 		},
-		{
-			name:     "query project with normal and recursive field resolver and aliases and multiple levels of recursion and aliases",
-			query:    `{ project(id: 2) { id name urgent: topPriorityItem(category: "task") { __typename } nextDeadline: criticalDeadline(withinDays: 10000) { __typename } subsub: subProjects { id name status otherSubs: subProjects { id name } } } }`,
-			expected: `{"data":{"project":{"id":"2","name":"Microservices Revolution","urgent":{"__typename":"Task"},"nextDeadline":{"__typename":"Milestone"},"subsub":[{"id":"4","name":"DevOps Transformation","status":"PLANNING","otherSubs":[{"id":"1","name":"Cloud Migration Overhaul"}]},{"id":"5","name":"Security Overhaul","status":"ON_HOLD","otherSubs":[{"id":"2","name":"Microservices Revolution"}]}]}}}`,
-		},
+	{
+		name:     "query project with normal and recursive field resolver and aliases and multiple levels of recursion and aliases",
+		query:    `{ project(id: 2) { id name urgent: topPriorityItem(category: "task") { __typename } nextDeadline: criticalDeadline(withinDays: 10000) { __typename } subsub: subProjects { id name status otherSubs: subProjects { id name } } } }`,
+		expected: `{"data":{"project":{"id":"2","name":"Microservices Revolution","urgent":{"__typename":"Task"},"nextDeadline":{"__typename":"Milestone"},"subsub":[{"id":"4","name":"DevOps Transformation","status":"PLANNING","otherSubs":[{"id":"1","name":"Cloud Migration Overhaul"}]},{"id":"5","name":"Security Overhaul","status":"ON_HOLD","otherSubs":[{"id":"2","name":"Microservices Revolution"}]}]}}}`,
+	},
+	{
+		name:     "query non-existent project returns null without invoking field resolvers",
+		query:    `{ project(id: 999) { id name topPriorityItem(category: "task") { __typename } criticalDeadline(withinDays: 10000) { __typename } } }`,
+		expected: `{"data":{"project":null}}`,
+	},
+	{
+		name:     "query non-existent project returns null without invoking recursive field resolvers",
+		query:    `{ project(id: 999) { id name subProjects { id name status subProjects { id name } } } }`,
+		expected: `{"data":{"project":null}}`,
+	},
+	{
+		name:     "query non-existent project returns null without invoking nested field resolvers with aliases",
+		query:    `{ project(id: 999) { id name urgent: topPriorityItem(category: "task") { __typename } nextDeadline: criticalDeadline(withinDays: 10000) { __typename } subsub: subProjects { id name status otherSubs: subProjects { id name } } } }`,
+		expected: `{"data":{"project":null}}`,
+	},
 	}
 	testenv.Run(t, &testenv.Config{
 		RouterConfigJSONTemplate: testenv.ConfigWithPluginsJSONTemplate,

router/go.mod

@@ -31,7 +31,7 @@ require (
 	github.com/tidwall/gjson v1.18.0
 	github.com/tidwall/sjson v1.2.5
 	github.com/twmb/franz-go v1.16.1
-	github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.257
+	github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.260
 	// Do not upgrade, it renames attributes we rely on
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.58.0
 	go.opentelemetry.io/contrib/propagators/b3 v1.23.0

router/go.sum

@@ -328,8 +328,8 @@ github.com/wundergraph/astjson v1.1.0 h1:xORDosrZ87zQFJwNGe/HIHXqzpdHOFmqWgykCLV
 github.com/wundergraph/astjson v1.1.0/go.mod h1:h12D/dxxnedtLzsKyBLK7/Oe4TAoGpRVC9nDpDrZSWw=
 github.com/wundergraph/go-arena v1.1.0 h1:9+wSRkJAkA2vbYHp6s8tEGhPViRGQNGXqPHT0QzhdIc=
 github.com/wundergraph/go-arena v1.1.0/go.mod h1:ROOysEHWJjLQ8FSfNxZCziagb7Qw2nXY3/vgKRh7eWw=
-github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.257 h1:hGsaKXRkH3o8DkyizY48/wC1Q+NB1nfD9EKVA7Gc81Y=
-github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.257/go.mod h1:gfmmrPd2khZONmwYE8RIfnGjwIG+RqL52jYiBzcUST8=
+github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.260 h1:mVls0cWupP3ob16NwYiOP7jcNQnp89Abz4d3kz3ss7c=
+github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.260/go.mod h1:gfmmrPd2khZONmwYE8RIfnGjwIG+RqL52jYiBzcUST8=
 github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zIM+UJPGz4=
 github.com/yosida95/uritemplate/v3 v3.0.2/go.mod h1:ILOh0sOhIJR3+L/8afwt/kE++YT040gmv5BQTMR2HP4=
 github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=