fix: Handle missing type in an SDL (sourcenetwork#3023)

## Relevant issue(s)

Resolves sourcenetwork#3022

## Description

Handles missing type in an SDL instead of panicing.

internal/request/graphql/schema/collection.go

@@ -454,7 +454,7 @@ func fieldsFromAST(
 	cTypeByFieldNameByObjName map[string]map[string]client.CType,
 	schemaOnly bool,
 ) ([]client.SchemaFieldDescription, []client.CollectionFieldDescription, error) {
-	kind, err := astTypeToKind(field.Type)
+	kind, err := astTypeToKind(hostObjectName, field)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -618,8 +618,11 @@ func setCRDTType(field *ast.FieldDefinition, kind client.FieldKind) (client.CTyp
 	return defaultCRDTForFieldKind[kind], nil
 }
 
-func astTypeToKind(t ast.Type) (client.FieldKind, error) {
-	switch astTypeVal := t.(type) {
+func astTypeToKind(
+	hostObjectName string,
+	field *ast.FieldDefinition,
+) (client.FieldKind, error) {
+	switch astTypeVal := field.Type.(type) {
 	case *ast.List:
 		switch innerAstTypeVal := astTypeVal.Type.(type) {
 		case *ast.NonNull:
@@ -677,7 +680,10 @@ func astTypeToKind(t ast.Type) (client.FieldKind, error) {
 		return client.FieldKind_None, ErrNonNullNotSupported
 
 	default:
-		return client.FieldKind_None, NewErrTypeNotFound(t.String())
+		if field.Type == nil {
+			return client.FieldKind_None, NewErrFieldTypeNotSpecified(hostObjectName, field.Name.Value)
+		}
+		return client.FieldKind_None, NewErrTypeNotFound(field.Type.String())
 	}
 }
 

internal/request/graphql/schema/errors.go

@@ -32,6 +32,7 @@ const (
 	errPolicyInvalidResourceProp     string = "policy directive with invalid resource property"
 	errDefaultValueInvalid           string = "default value type must match field type"
 	errDefaultValueNotAllowed        string = "default value is not allowed for this field type"
+	errFieldTypeNotSpecified         string = "field type not specified"
 )
 
 var (
@@ -58,6 +59,7 @@ var (
 	ErrPolicyWithUnknownArg      = errors.New(errPolicyUnknownArgument)
 	ErrPolicyInvalidIDProp       = errors.New(errPolicyInvalidIDProp)
 	ErrPolicyInvalidResourceProp = errors.New(errPolicyInvalidResourceProp)
+	ErrFieldTypeNotSpecified     = errors.New(errFieldTypeNotSpecified)
 )
 
 func NewErrDuplicateField(objectName, fieldName string) error {
@@ -155,3 +157,11 @@ func NewErrDefaultValueNotAllowed(fieldName, fieldType string) error {
 		errors.NewKV("Type", fieldType),
 	)
 }
+
+func NewErrFieldTypeNotSpecified(objectName, fieldName string) error {
+	return errors.New(
+		errFieldTypeNotSpecified,
+		errors.NewKV("Object", objectName),
+		errors.NewKV("Field", fieldName),
+	)
+}

tests/integration/schema/nil_type_test.go

@@ -0,0 +1,34 @@
+// Copyright 2024 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package schema
+
+import (
+	"testing"
+
+	testUtils "github.com/sourcenetwork/defradb/tests/integration"
+)
+
+func TestSchema_WithMissingType_Errors(t *testing.T) {
+	test := testUtils.TestCase{
+		Actions: []any{
+			testUtils.SchemaUpdate{
+				Schema: `
+					type User {
+						name:
+					}
+				`,
+				ExpectedError: "field type not specified. Object: User, Field: name",
+			},
+		},
+	}
+
+	testUtils.ExecuteTestCase(t, test)
+}