Fix incorrect code gen for string fields with default values

csharp/src/Google.Protobuf.Test/TestProtos/Unittest.cs

@@ -882,7 +882,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
     public static readonly pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, bool> DefaultBoolExtension =
       new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, bool>(73, pb::FieldCodec.ForBool(584, true));
     public static readonly pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string> DefaultStringExtension =
-      new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string>(74, pb::FieldCodec.ForString(594, global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +aGVsbG8= +"))));
+      new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string>(74, pb::FieldCodec.ForString(594, global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("aGVsbG8="))));
     public static readonly pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, pb::ByteString> DefaultBytesExtension =
       new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, pb::ByteString>(75, pb::FieldCodec.ForBytes(602, pb::ByteString.FromBase64("d29ybGQ=")));
     public static readonly pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, global::Google.Protobuf.TestProtos.Proto2.TestAllTypes.Types.NestedEnum> DefaultNestedEnumExtension =
@@ -892,9 +892,9 @@ namespace Google.Protobuf.TestProtos.Proto2 {
     public static readonly pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, global::Google.Protobuf.TestProtos.Proto2.ImportEnum> DefaultImportEnumExtension =
       new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, global::Google.Protobuf.TestProtos.Proto2.ImportEnum>(83, pb::FieldCodec.ForEnum(664, x => (int) x, x => (global::Google.Protobuf.TestProtos.Proto2.ImportEnum) x, global::Google.Protobuf.TestProtos.Proto2.ImportEnum.ImportBar));
     public static readonly pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string> DefaultStringPieceExtension =
-      new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string>(84, pb::FieldCodec.ForString(674, global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +YWJj +"))));
+      new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string>(84, pb::FieldCodec.ForString(674, global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("YWJj"))));
     public static readonly pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string> DefaultCordExtension =
-      new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string>(85, pb::FieldCodec.ForString(682, global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +MTIz +"))));
+      new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string>(85, pb::FieldCodec.ForString(682, global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("MTIz"))));
     /// <summary>
     /// For oneof test
     /// </summary>
@@ -2415,7 +2415,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "default_string" field.</summary>
     public const int DefaultStringFieldNumber = 74;
-    private readonly static string DefaultStringDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +aGVsbG8= +"));
+    private readonly static string DefaultStringDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("aGVsbG8="));
 
     private string defaultString_;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2533,7 +2533,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "default_string_piece" field.</summary>
     public const int DefaultStringPieceFieldNumber = 84;
-    private readonly static string DefaultStringPieceDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +YWJj +"));
+    private readonly static string DefaultStringPieceDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("YWJj"));
 
     private string defaultStringPiece_;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2556,7 +2556,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "default_cord" field.</summary>
     public const int DefaultCordFieldNumber = 85;
-    private readonly static string DefaultCordDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +MTIz +"));
+    private readonly static string DefaultCordDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("MTIz"));
 
     private string defaultCord_;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -6292,7 +6292,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
       /// compile.
       /// </summary>
       public static readonly pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string> Test =
-        new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string>(1002, pb::FieldCodec.ForString(8018, global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +dGVzdA== +"))));
+        new pb::Extension<global::Google.Protobuf.TestProtos.Proto2.TestAllExtensions, string>(1002, pb::FieldCodec.ForString(8018, global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("dGVzdA=="))));
       /// <summary>
       /// Used to test if generated extension name is correct when there are
       /// underscores.
@@ -13094,7 +13094,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "utf8_string" field.</summary>
     public const int Utf8StringFieldNumber = 6;
-    private readonly static string Utf8StringDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +4Yi0 +"));
+    private readonly static string Utf8StringDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("4Yi0"));
 
     private string utf8String_;
     /// <summary>
@@ -13443,7 +13443,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "cpp_trigraph" field.</summary>
     public const int CppTrigraphFieldNumber = 20;
-    private readonly static string CppTrigraphDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +PyA/ID8/ID8/ID8/PyA/Py8gPz8t +"));
+    private readonly static string CppTrigraphDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("PyA/ID8/ID8/ID8/PyA/Py8gPz8t"));
 
     private string cppTrigraph_;
     /// <summary>
@@ -13473,7 +13473,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "string_with_zero" field.</summary>
     public const int StringWithZeroFieldNumber = 23;
-    private readonly static string StringWithZeroDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +aGVsAGxv +"));
+    private readonly static string StringWithZeroDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("aGVsAGxv"));
 
     private string stringWithZero_;
     /// <summary>
@@ -13522,7 +13522,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "string_piece_with_zero" field.</summary>
     public const int StringPieceWithZeroFieldNumber = 25;
-    private readonly static string StringPieceWithZeroDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +YWIAYw== +"));
+    private readonly static string StringPieceWithZeroDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("YWIAYw=="));
 
     private string stringPieceWithZero_;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -13545,7 +13545,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "cord_with_zero" field.</summary>
     public const int CordWithZeroFieldNumber = 26;
-    private readonly static string CordWithZeroDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +MTIAMw== +"));
+    private readonly static string CordWithZeroDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("MTIAMw=="));
 
     private string cordWithZero_;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -13568,7 +13568,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "replacement_string" field.</summary>
     public const int ReplacementStringFieldNumber = 27;
-    private readonly static string ReplacementStringDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +JHt1bmtub3dufQ== +"));
+    private readonly static string ReplacementStringDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("JHt1bmtub3dufQ=="));
 
     private string replacementString_;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -16784,7 +16784,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
     public const int BarStringFieldNumber = 13;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public string BarString {
-      get { return HasBarString ? (string) bar_ : global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +U1RSSU5H +")); }
+      get { return HasBarString ? (string) bar_ : global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("U1RSSU5H")); }
       set {
         bar_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
         barCase_ = BarOneofCase.BarString;
@@ -16807,7 +16807,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
     public const int BarCordFieldNumber = 14;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public string BarCord {
-      get { return HasBarCord ? (string) bar_ : global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +Q09SRA== +")); }
+      get { return HasBarCord ? (string) bar_ : global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("Q09SRA==")); }
       set {
         bar_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
         barCase_ = BarOneofCase.BarCord;
@@ -16830,7 +16830,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
     public const int BarStringPieceFieldNumber = 15;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public string BarStringPiece {
-      get { return HasBarStringPiece ? (string) bar_ : global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +U1BJRUNF +")); }
+      get { return HasBarStringPiece ? (string) bar_ : global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("U1BJRUNF")); }
       set {
         bar_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
         barCase_ = BarOneofCase.BarStringPiece;
@@ -16921,7 +16921,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "baz_string" field.</summary>
     public const int BazStringFieldNumber = 19;
-    private readonly static string BazStringDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +QkFa +"));
+    private readonly static string BazStringDefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("QkFa"));
 
     private string bazString_;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -21185,7 +21185,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     /// <summary>Field number for the "a" field.</summary>
     public const int AFieldNumber = 1;
-    private readonly static string ADefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(" +Ki8gPC0gTmVpdGhlciBzaG91bGQgdGhpcy4= +"));
+    private readonly static string ADefaultValue = global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String("Ki8gPC0gTmVpdGhlciBzaG91bGQgdGhpcy4="));
 
     private string a_;
     /// <summary>

src/google/protobuf/compiler/csharp/csharp_field_base.cc

@@ -306,7 +306,7 @@ std::string FieldGeneratorBase::GetStringDefaultValueInternal(const FieldDescrip
     if (descriptor->default_value_string().empty())
         return "\"\"";
     else
-        return "global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(\" +" + StringToBase64(descriptor->default_value_string()) + " +\"))";
+        return "global::System.Text.Encoding.UTF8.GetString(global::System.Convert.FromBase64String(\"" + StringToBase64(descriptor->default_value_string()) + "\"))";
 }
 
 std::string FieldGeneratorBase::GetBytesDefaultValueInternal(const FieldDescriptor* descriptor) {