[Rust] Ensure unions are referenced with the correct path (#6422)

* Add codegen test for namespaced unions

* [Rust] Handle cross-namespace union use

* [Rust] Test namespace handling

* [Rust] Drop trailing whitespace in codegen

* [Rust] Set flags in generate_code.bat to match .sh

* [C#] Add additional namespace test file

tests/namespace_test/NamespaceA/NamespaceB/UnionInNestedNS.cs

@@ -0,0 +1,77 @@
+// <auto-generated>
+//  automatically generated by the FlatBuffers compiler, do not modify
+// </auto-generated>
+
+namespace NamespaceA.NamespaceB
+{
+
+[Newtonsoft.Json.JsonConverter(typeof(Newtonsoft.Json.Converters.StringEnumConverter))]
+public enum UnionInNestedNS : byte
+{
+  NONE = 0,
+  TableInNestedNS = 1,
+};
+
+public class UnionInNestedNSUnion {
+  public UnionInNestedNS Type { get; set; }
+  public object Value { get; set; }
+
+  public UnionInNestedNSUnion() {
+    this.Type = UnionInNestedNS.NONE;
+    this.Value = null;
+  }
+
+  public T As<T>() where T : class { return this.Value as T; }
+  public NamespaceA.NamespaceB.TableInNestedNST AsTableInNestedNS() { return this.As<NamespaceA.NamespaceB.TableInNestedNST>(); }
+
+  public static int Pack(FlatBuffers.FlatBufferBuilder builder, UnionInNestedNSUnion _o) {
+    switch (_o.Type) {
+      default: return 0;
+      case UnionInNestedNS.TableInNestedNS: return NamespaceA.NamespaceB.TableInNestedNS.Pack(builder, _o.AsTableInNestedNS()).Value;
+    }
+  }
+}
+
+public class UnionInNestedNSUnion_JsonConverter : Newtonsoft.Json.JsonConverter {
+  public override bool CanConvert(System.Type objectType) {
+    return objectType == typeof(UnionInNestedNSUnion) || objectType == typeof(System.Collections.Generic.List<UnionInNestedNSUnion>);
+  }
+  public override void WriteJson(Newtonsoft.Json.JsonWriter writer, object value, Newtonsoft.Json.JsonSerializer serializer) {
+    var _olist = value as System.Collections.Generic.List<UnionInNestedNSUnion>;
+    if (_olist != null) {
+      writer.WriteStartArray();
+      foreach (var _o in _olist) { this.WriteJson(writer, _o, serializer); }
+      writer.WriteEndArray();
+    } else {
+      this.WriteJson(writer, value as UnionInNestedNSUnion, serializer);
+    }
+  }
+  public void WriteJson(Newtonsoft.Json.JsonWriter writer, UnionInNestedNSUnion _o, Newtonsoft.Json.JsonSerializer serializer) {
+    if (_o == null) return;
+    serializer.Serialize(writer, _o.Value);
+  }
+  public override object ReadJson(Newtonsoft.Json.JsonReader reader, System.Type objectType, object existingValue, Newtonsoft.Json.JsonSerializer serializer) {
+    var _olist = existingValue as System.Collections.Generic.List<UnionInNestedNSUnion>;
+    if (_olist != null) {
+      for (var _j = 0; _j < _olist.Count; ++_j) {
+        reader.Read();
+        _olist[_j] = this.ReadJson(reader, _olist[_j], serializer);
+      }
+      reader.Read();
+      return _olist;
+    } else {
+      return this.ReadJson(reader, existingValue as UnionInNestedNSUnion, serializer);
+    }
+  }
+  public UnionInNestedNSUnion ReadJson(Newtonsoft.Json.JsonReader reader, UnionInNestedNSUnion _o, Newtonsoft.Json.JsonSerializer serializer) {
+    if (_o == null) return null;
+    switch (_o.Type) {
+      default: break;
+      case UnionInNestedNS.TableInNestedNS: _o.Value = serializer.Deserialize<NamespaceA.NamespaceB.TableInNestedNST>(reader); break;
+    }
+    return _o;
+  }
+}
+
+
+}

tests/namespace_test/NamespaceA/NamespaceB/UnionInNestedNS.go

@@ -0,0 +1,36 @@
+// Code generated by the FlatBuffers compiler. DO NOT EDIT.
+
+package NamespaceB
+
+import (
+	"strconv"
+
+	flatbuffers "github.com/google/flatbuffers/go"
+
+	NamespaceA__NamespaceB "NamespaceA/NamespaceB"
+)
+
+type UnionInNestedNST struct {
+	Type UnionInNestedNS
+	Value interface{}
+}
+
+func (t *UnionInNestedNST) Pack(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
+	if t == nil {
+		return 0
+	}
+	switch t.Type {
+	case UnionInNestedNSTableInNestedNS:
+		return t.Value.(*NamespaceA__NamespaceB.TableInNestedNST).Pack(builder)
+	}
+	return 0
+}
+
+func (rcv UnionInNestedNS) UnPack(table flatbuffers.Table) *UnionInNestedNST {
+	switch rcv {
+	case UnionInNestedNSTableInNestedNS:
+		x := TableInNestedNS{_tab: table}
+		return &NamespaceA__NamespaceB.UnionInNestedNST{ Type: UnionInNestedNSTableInNestedNS, Value: x.UnPack() }
+	}
+	return nil
+}

tests/namespace_test/NamespaceA/NamespaceB/UnionInNestedNS.java

@@ -0,0 +1,14 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+
+package NamespaceA.NamespaceB;
+
+public final class UnionInNestedNS {
+  private UnionInNestedNS() { }
+  public static final byte NONE = 0;
+  public static final byte TableInNestedNS = 1;
+
+  public static final String[] names = { "NONE", "TableInNestedNS", };
+
+  public static String name(int e) { return names[e]; }
+}
+

tests/namespace_test/NamespaceA/NamespaceB/UnionInNestedNS.kt

@@ -0,0 +1,14 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+
+package NamespaceA.NamespaceB
+
+@Suppress("unused")
+@ExperimentalUnsignedTypes
+class UnionInNestedNS private constructor() {
+    companion object {
+        const val NONE: UByte = 0u
+        const val TableInNestedNS: UByte = 1u
+        val names : Array<String> = arrayOf("NONE", "TableInNestedNS")
+        fun name(e: Int) : String = names[e]
+    }
+}

tests/namespace_test/NamespaceA/NamespaceB/UnionInNestedNS.lua

@@ -0,0 +1,10 @@
+-- automatically generated by the FlatBuffers compiler, do not modify
+
+-- namespace: NamespaceB
+
+local UnionInNestedNS = {
+    NONE = 0,
+    TableInNestedNS = 1,
+}
+
+return UnionInNestedNS -- return the module

tests/namespace_test/NamespaceA/NamespaceB/UnionInNestedNS.php

@@ -0,0 +1,23 @@
+<?php
+// automatically generated by the FlatBuffers compiler, do not modify
+
+namespace NamespaceA\NamespaceB;
+
+class UnionInNestedNS
+{
+    const NONE = 0;
+    const TableInNestedNS = 1;
+
+    private static $names = array(
+        UnionInNestedNS::NONE=>"NONE",
+        UnionInNestedNS::TableInNestedNS=>"TableInNestedNS",
+    );
+
+    public static function Name($e)
+    {
+        if (!isset(self::$names[$e])) {
+            throw new \Exception();
+        }
+        return self::$names[$e];
+    }
+}

tests/namespace_test/NamespaceA/NamespaceB/UnionInNestedNS.py

@@ -0,0 +1,12 @@
+# automatically generated by the FlatBuffers compiler, do not modify
+
+# namespace: NamespaceB
+
+
+def UnionInNestedNSCreator(unionType, table):
+    from flatbuffers.table import Table
+    if not isinstance(table, Table):
+        return None
+    if unionType == UnionInNestedNS().TableInNestedNS:
+        return TableInNestedNST.InitFromBuf(table.Bytes, table.Pos)
+    return None