Stub Environment from registry apis inside app-containers. (CoreCLR) (dotnet/coreclr...

We're not going to get exemptions for these inside appcontainers
so we'll change them to behave as they do on Unix (present
an empty reg key that eats writes requests.)

Commit migrated from https://github.com/dotnet/coreclr/commit/c1456fe280d5ea5e3e2f99024d905ce85439493c

diff --git a/src/coreclr/src/mscorlib/src/System/Environment.cs b/src/coreclr/src/mscorlib/src/System/Environment.cs
index cd25967..e634341 100644 (file)
--- a/src/coreclr/src/mscorlib/src/System/Environment.cs
+++ b/src/coreclr/src/mscorlib/src/System/Environment.cs
@@ -585,9 +585,13 @@ namespace System
             if (target == EnvironmentVariableTarget.Process)
                 return GetEnvironmentVariableCore(variable);
 
-#if !FEATURE_WIN32_REGISTRY
-            return null;
-#else
+#if FEATURE_WIN32_REGISTRY
+            if (AppDomain.IsAppXModel())
+#endif
+            {
+                return null;
+            }
+#if FEATURE_WIN32_REGISTRY
             RegistryKey baseKey;
             string keyName;
 
@@ -670,11 +674,15 @@ namespace System
 
         internal static IEnumerable<KeyValuePair<string, string>> EnumerateEnvironmentVariablesFromRegistry(EnvironmentVariableTarget target)
         {
-#if !FEATURE_WIN32_REGISTRY
-            // Without registry support we have nothing to return
-            ValidateTarget(target);
-            yield break;
-#else
+#if FEATURE_WIN32_REGISTRY
+            if (AppDomain.IsAppXModel())
+#endif
+            {
+                // Without registry support we have nothing to return
+                ValidateTarget(target);
+                yield break;
+            }
+#if FEATURE_WIN32_REGISTRY
             RegistryKey baseKey;
             string keyName;
             if (target == EnvironmentVariableTarget.Machine)
@@ -740,10 +748,14 @@ namespace System
                 return;
             }
 
-#if !FEATURE_WIN32_REGISTRY
-            // other targets ignored
-            return;
-#else
+#if FEATURE_WIN32_REGISTRY
+            if (AppDomain.IsAppXModel())
+#endif
+            {
+                // other targets ignored
+                return;
+            }
+#if FEATURE_WIN32_REGISTRY
             // explicitly null out value if is the empty string.
             if (string.IsNullOrEmpty(value) || value[0] == '\0')
                 value = null;