Release Notes Mono 3.10.0

Release date: 04 Oct 2014

Mono 3.10.0 is a bugfix release with a few features.


  • Implemented System.IO.Compression.FileSystem.
  • Uri now implements the .NET 4.5 behavior. It can be reverted to the old behavior by setting enviromnent variable MONO_URI_IRIPARSING to false or by setting the System.Uri::s_IriParsing static field to false. The code to do this is shown below:
FieldInfo iriParsingField = typeof (Uri).GetField ("s_IriParsing",
    BindingFlags.Static | BindingFlags.GetField | BindingFlags.NonPublic);
if (iriParsingField != null)
    iriParsingField.SetValue (null, false);


  • Remove unnecessary locking from core metadata parsing functions.
  • Avoid cache thrashing of locals array when looping over enumerator.

Known Issues

The OSX packages have an invalid libgdiplus library that affects users of System.Drawing that requires it to work.
This specially affects Xamarin.Mac users that fit the following criteria:

  • Uses Xamarin.Mac Classic (Unified is unaffected).
  • Uses the subsets of System.Drawing that use libgdiplus.dylib internally
    - System.Drawing.RectangleF, PointF, Colors are unaffected
    - System.Drawing.Bitmap, and font for example are affected

The symptom of the problem is your application failing with: “System.TypeInitializationException: An exception was thrown by the type initializer for System.Drawing.GDIPlus —> System.Exception: GdiplusStartup”

Bug fixes


  • Fix support for unaligned offsets in the store_membase_imm opcodes. Fixes #23267.
  • Fix the lookup of nested types which have a namespace. Fixes #21653.
  • Increase some opcode sizes. Fixes #23026.
  • Always pass the imt arg to interface calls in gsharedvt methods. Fixes #22624.
  • Store the epilog length in MonoArchEHJitInfo instead of encoding it in jinfo->unwind_desc, since the latter can overflow for methods with large epilogs. Fixes #22685.
  • Add a mono_thread_detach_if_exiting () public api function which can be called by embedding code to detach the runtime if the code is running from a pthread dtor. Fixes #21164.
  • Fix yet another native types problem. Fixes #22053.
  • Fix the leaking of mach ports introduced by 98bbf8512aec0fa01b4426583280f6d231d22187. Fixes #22068.
  • Add support for constrained calls with vtype return types in gsharedvt code. Fixes #22109.
  • Fix the PLATFORM_GNU check so it works with gnueabi etc. as well. Fixes #21520.
  • Don’t make runtime invoke signatures generic. Fixes #21973.
  • Allow v8..v15 in unwind info on arm64. Fixes part of #21615.
  • Fix Process.PrivateMemorySize64 etc. on ios. Fixes #21882.
  • Fix enum->int casts in gsharedvt code. Fixes #21893.
  • Don’t assert when loading a generic methodspec with 0 arity. Fixes #19097.
  • Avoid asserting when a cattr cannot be loaded. Fixes #21653.
  • Avoid making generic calls from gsharedvt methods normally, go through the rgctx infrastructure instead. Fixes #21677.

Class Libraries

  • Fix Uri UserInfo parsing. Fixes 23246.
  • Update RequestMessage.RequestUri.AbsoluteUri after redirect. Fixes #22383.
  • Fixes XContainer attempt to create a XNode from a null value. Fixes #20151.
  • Changed XObject OnChanged and OnChanging to use Owner. When XObject.Owner is not a XElement XObject.Parent returns null and the owner would not be notified of changing and changed events. Fixes #18772.
  • Process XslLiteralElements with only child attributes as empty ones. Fixes #14751.
  • ‘finally’ protect ClientRuntimeChannel.Begin/EndProcess(). Fixes #22179.
  • WebClient.OpenWrite() must get the response on close. Fixes #10163.
  • Fix WebClient.UploadValuesTaskAsync(); Fixes #20359.
  • Improve System.Security.Claims. Fixes #22282.
  • Fixed serialization of XmlNode field with attribute XmlAnyElement. Fixes #3211.
  • Handle String::Format with escaped closing }. Fixes #22114
  • Add a missing check to TypeBuilder.CreateType (). Fixes #22059.
  • Xml Serialization of Base class w/o a parameterless constructor. Removed validation code that did not allowed serialization of base classes without a parameterless constructor. Fixes #6913.
  • Fixed XmlSerializer to handle attribute XmlSchemePrivider.IsAny. XmlSerializer no longer outputs a root element with class name when the class has the attribute XmlSchemeProvider and IsAny is true. Fixes #11916
  • Test that DeflateStream.Read does read an empty stream. Covers #19313.
  • Reseting all private key values to null is required because a new import may not overwrite existing values. Fixes #18482.
  • Handle quoted filename value. Fixes #21960.
  • Dispose XmlReader using correct value. Fixes #21771.

C# Compiler

  • Don’t use `1 naming for compiler generated second level and deeper nested types. Fixes #22893.
  • Extend missing type check to type lookups. Fixes #20933.
  • Fix copy and paste error in constraints checker. Fixes #22131.
  • Speed up nullable tokenizer. Fixes #20195.
  • Coalescing operator if the lhs of a null is a integer type that is larger than the integer type on the rhs. Fixes #22054.
  • Check for duplicate destructors. Fixes #21983.
  • Switch statement with constant block at first label. Fixes #21805.
  • Decimal constants modulo folding. Fixes #21743.
  • Update codegen for boolean loads. Fixes #21685.


  • Workaround for issues with CreateItem task where metadata are not generated due to up-to-data inputs. Fixes #23022.
  • Add KeepDuplicates etc. to 4.0 as internal. Fixes #20961.