Fix panics on invalid Node ID args (#185)

* Fix panics on invalid Node ID args
* Add path to internal gateway resolver errors

.github/workflows/run-tests.yml

@@ -13,7 +13,7 @@ jobs:
     steps:
       - uses: actions/setup-go@v3
         with:
-          go-version: ^1.18
+          go-version: 1.18.x  # Avoid latest here. New Go versions can break linters.
       - uses: actions/checkout@v3
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v3

gateway.go

@@ -2,6 +2,7 @@ package gateway
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"strings"
@@ -311,8 +312,19 @@ func makeNodeField() *QueryField {
 			},
 		},
 		Resolver: func(ctx context.Context, args map[string]interface{}) (string, error) {
-			// pass it to the user
-			return args["id"].(string), nil
+			id := args["id"]
+			if id == nil {
+				return "", fmt.Errorf("argument 'id' is required")
+			}
+			idStr, ok := id.(string)
+			if !ok {
+				jsonID, err := json.Marshal(id)
+				if err != nil {
+					return "", fmt.Errorf("invalid ID type")
+				}
+				return "", fmt.Errorf("invalid ID type: %s", string(jsonID))
+			}
+			return idStr, nil
 		},
 	}
 }

internal.go

@@ -101,7 +101,10 @@ func (g *Gateway) Query(ctx context.Context, input *graphql.QueryInput, receiver
 					// find the id of the entity
 					id, err := qField.Resolver(ctx, args)
 					if err != nil {
-						return err
+						return &graphql.Error{
+							Message: err.Error(),
+							Path:    []interface{}{field.Alias},
+						}
 					}
 
 					// assign the id to the response

internal_test.go

@@ -321,3 +321,127 @@ func TestSchema_resolveNodeIDFromArg(t *testing.T) {
 		ID string `json:"id"`
 	}{ID: "my-id"}}, result)
 }
+
+func TestSchema_resolveNodeWrongIDType(t *testing.T) {
+	t.Parallel()
+	type Node struct {
+		ID *string `json:"id"`
+	}
+	type Result struct {
+		Node Node `json:"node"`
+	}
+	var result Result
+
+	query := `
+		{
+			node(id: 123) {
+				id
+			}
+		}
+	`
+
+	err := schemaTestLoadQuery(query, result, map[string]interface{}{})
+	assert.Equal(t, graphql.ErrorList{
+		&graphql.Error{
+			Message: "invalid ID type: 123",
+			Path:    []interface{}{"node"},
+		},
+	}, err)
+	assert.Equal(t, Result{
+		Node: Node{ID: nil},
+	}, result)
+}
+
+func TestSchema_resolveNodeMissingIDArg(t *testing.T) {
+	t.Parallel()
+	type Node struct {
+		ID *string `json:"id"`
+	}
+	type Result struct {
+		Node Node `json:"node"`
+	}
+	var result Result
+
+	query := `
+		query ($id: ID!) {
+			node(id: $id) {
+				id
+			}
+		}
+	`
+	variables := map[string]interface{}{} // missing ID arg
+
+	err := schemaTestLoadQuery(query, result, variables)
+	assert.Equal(t, graphql.ErrorList{
+		&graphql.Error{
+			Message: "argument 'id' is required",
+			Path:    []interface{}{"node"},
+		},
+	}, err)
+	assert.Equal(t, Result{
+		Node: Node{ID: nil},
+	}, result)
+}
+
+func TestSchema_resolveNodeWrongIDArgType(t *testing.T) {
+	t.Parallel()
+	type Node struct {
+		ID *string `json:"id"`
+	}
+	type Result struct {
+		Node Node `json:"node"`
+	}
+	var result Result
+
+	query := `
+		query ($id: ID!) {
+			node(id: $id) {
+				id
+			}
+		}
+	`
+	variables := map[string]interface{}{
+		"id": 123,
+	}
+
+	err := schemaTestLoadQuery(query, result, variables)
+	assert.Equal(t, graphql.ErrorList{
+		&graphql.Error{
+			Message: "invalid ID type: 123",
+			Path:    []interface{}{"node"},
+		},
+	}, err)
+	assert.Equal(t, Result{
+		Node: Node{ID: nil},
+	}, result)
+}
+
+func TestSchema_resolveNodeWrongIDTypeWithAlias(t *testing.T) {
+	t.Parallel()
+	type Node struct {
+		ID *string `json:"id"`
+	}
+	type Result struct {
+		Node Node `json:"node"`
+	}
+	var result Result
+
+	query := `
+		{
+			myAlias: node(id: 123) {
+				id
+			}
+		}
+	`
+
+	err := schemaTestLoadQuery(query, result, map[string]interface{}{})
+	assert.Equal(t, graphql.ErrorList{
+		&graphql.Error{
+			Message: "invalid ID type: 123",
+			Path:    []interface{}{"myAlias"},
+		},
+	}, err)
+	assert.Equal(t, Result{
+		Node: Node{ID: nil},
+	}, result)
+}