Partially fixed.

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/Types/Extensions.cs

@@ -19,19 +19,26 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types
         public static IEnumerable<(T Field, string Name, string Type)> SafeFields<T>(this IEnumerable<T> fields) where T : IField
         {
             var allFields =
-                fields.ForApi()
-                    .Select(f => (Field: f, Name: f.Name.ToCamelCase(), Type: f.TypeName())).GroupBy(x => x.Name)
-                    .Select(g =>
-                    {
-                        return g.Select((f, i) => (f.Field, f.Name.SafeString(i), f.Type.SafeString(i)));
-                    })
+                fields.FieldNames()
+                    .GroupBy(x => x.Name)
+                    .Select(g => g.Select((f, i) => (f.Field, f.Name.SafeString(i), f.Type.SafeString(i))))
                     .SelectMany(x => x);
 
             return allFields;
         }
 
+        private static IEnumerable<(T Field, string Name, string Type)> FieldNames<T>(this IEnumerable<T> fields) where T : IField
+        {
+            return fields.ForApi().Select(field => (field, field.Name.ToCamelCase(), field.TypeName()));
+        }
+
         private static string SafeString(this string value, int index)
         {
+            if (value.Length > 0 && !char.IsLetter(value[0]))
+            {
+                value = "gql_" + value;
+            }
+
             if (index > 0)
             {
                 return value + (index + 1);

backend/tests/Squidex.Domain.Apps.Entities.Tests/Contents/GraphQL/GraphQLQueriesTests.cs

@@ -784,7 +784,7 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
         }
 
         [Fact]
-        public async Task Should_return_single_content_with_duplicate_names()
+        public async Task Should_return_single_content_with_fixed_names()
         {
             var contentId = Guid.NewGuid();
             var content = CreateContent(contentId, Guid.Empty, Guid.Empty);
@@ -793,6 +793,12 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
                 query {
                   findMySchemaContent(id: ""<ID>"") {
                     data {
+                      gql_2Numbers {
+                        iv
+                      }
+                      gql_2Numbers2 {
+                        iv
+                      }
                       myNumber {
                         iv
                       }
@@ -822,6 +828,14 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
                     {
                         data = new
                         {
+                            gql_2Numbers = new
+                            {
+                                iv = 22
+                            },
+                            gql_2Numbers2 = new
+                            {
+                                iv = 23
+                            },
                             myNumber = new
                             {
                                 iv = 1

backend/tests/Squidex.Domain.Apps.Entities.Tests/Contents/GraphQL/GraphQLTestBase.cs

@@ -88,6 +88,10 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
                         .AddBoolean(121, "nested-boolean")
                         .AddNumber(122, "nested-number")
                         .AddNumber(123, "nested_number"))
+                    .AddNumber(14, "2_numbers", Partitioning.Invariant,
+                        new NumberFieldProperties())
+                    .AddNumber(15, "2-numbers", Partitioning.Invariant,
+                        new NumberFieldProperties())
                     .SetScripts(new SchemaScripts { Query = "<query-script>" });
 
             schema = Mocks.Schema(appId, schemaId, schemaDef);
@@ -123,6 +127,12 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
                     .AddField("my-assets",
                         new ContentFieldData()
                             .AddValue("iv", JsonValue.Array(assetId.ToString())))
+                    .AddField("2_numbers",
+                        new ContentFieldData()
+                            .AddValue("iv", 22))
+                    .AddField("2-numbers",
+                        new ContentFieldData()
+                            .AddValue("iv", 23))
                     .AddField("my-number",
                         new ContentFieldData()
                             .AddValue("iv", 1.0))