From 994d609f9448246cfc3e2790455944d155a73057 Mon Sep 17 00:00:00 2001
From: "Cronyn, Ivan (London)" <ivan.cronyn@man.com>
Date: Wed, 7 Feb 2018 17:01:37 +0000
Subject: [PATCH] Fixes issue where private types are returned

---
 AUTHORS.md                     |  3 ++-
 CHANGELOG.md                   |  1 +
 src/runtime/assemblymanager.cs | 18 +++++++++++++++++-
 src/tests/test_import.py       | 11 +++++++++++
 4 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/AUTHORS.md b/AUTHORS.md
index 78bb25f9e..66e025039 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -23,7 +23,8 @@
 -   David Lechner ([@dlech](https://github.com/dlech))
 -   Dmitriy Se ([@dmitriyse](https://github.com/dmitriyse))
 -   He-chien Tsai ([@t3476](https://github.com/t3476))
--   Jeff Reback ([@jreback](https://github.com/jreback))
+-   Ivan Cronyn ([@cronan](https://github.com/cronan))
+-   Jeff Reback ([@jreback](https://github.com/jreback))
 -   Joe Frayne ([@jfrayne](https://github.com/jfrayne))
 -   John Burnett ([@johnburnett](https://github.com/johnburnett))
 -   Luke Stratman ([@lstratman](https://github.com/lstratman))
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 380c6f6d3..612ab61e3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -29,6 +29,7 @@ This document follows the conventions laid out in [Keep a CHANGELOG][].
 -   Fixed 'clrmethod' for python 2 (#492)
 -   Fixed double calling of constructor when deriving from .NET class (#495)
 -   Fixed `clr.GetClrType` when iterating over `System` members (#607) 
+-   Fixed bug where private types are returned when public types exist (#622)
 
 
 ## [2.3.0][] - 2017-03-11
diff --git a/src/runtime/assemblymanager.cs b/src/runtime/assemblymanager.cs
index 06a4449a2..8e24d7921 100644
--- a/src/runtime/assemblymanager.cs
+++ b/src/runtime/assemblymanager.cs
@@ -6,6 +6,7 @@
 using System.IO;
 using System.Reflection;
 using System.Threading;
+using System.Linq;
 
 namespace Python.Runtime
 {
@@ -448,17 +449,32 @@ public static List<string> GetNames(string nsname)
         /// Returns the System.Type object for a given qualified name,
         /// looking in the currently loaded assemblies for the named
         /// type. Returns null if the named type cannot be found.
+        /// If more than one is found, returns the first public type
         /// </summary>
         public static Type LookupType(string qname)
         {
+            List<Type> foundTypes = new List<Type>();
+
             foreach (Assembly assembly in assemblies)
             {
                 Type type = assembly.GetType(qname);
                 if (type != null)
                 {
-                    return type;
+                    foundTypes.Add(type);
                 }
             }
+
+            Func<Type, bool> criteria = (t) => t.IsPublic;
+
+            if(foundTypes.Any(criteria))
+            {
+                return foundTypes.First(criteria);
+            }
+            else if (foundTypes.Any())
+            {
+                return foundTypes.First();
+            }
+
             return null;
         }
 
diff --git a/src/tests/test_import.py b/src/tests/test_import.py
index 42cafc4df..90daa40f0 100644
--- a/src/tests/test_import.py
+++ b/src/tests/test_import.py
@@ -11,3 +11,14 @@ def test_relative_missing_import():
     Relative import in the site-packages folder"""
     with pytest.raises(ImportError):
         from . import _missing_import
+
+
+def test_private_and_public_types_import():
+    """Tests that importing a type where private and public 
+    versions exist imports the public version. In .Net Core 
+    2.0 there are public and private versions of the same 
+    types in different assemblies. For example, there is a 
+    private version of System.Environment in mscorlib.dll, 
+    and a public version in System.Runtime.Extensions.dll."""
+    from System import Environment
+    assert len(Environment.MachineName) > 0