Throw PNSE on browser

src/libraries/System.Runtime.Serialization.Formatters/src/System.Runtime.Serialization.Formatters.csproj

@@ -5,6 +5,10 @@
     <TargetFrameworks>$(NetCoreAppCurrent)</TargetFrameworks>
     <Nullable>enable</Nullable>
   </PropertyGroup>
+  <PropertyGroup>
+    <!-- On certain runtimes BinaryFormatter isn't supported at all. -->
+    <DefineConstants Condition="'$(TargetsBrowser)' == 'true'">$(DefineConstants);BINARYFORMATTER_PNSE</DefineConstants>
+  </PropertyGroup>
   <ItemGroup>
     <Compile Include="System.Runtime.Serialization.Formatters.TypeForwards.cs" />
     <Compile Include="System\Runtime\Serialization\DeserializationEventHandler.cs" />

src/libraries/System.Runtime.Serialization.Formatters/src/System/Runtime/Serialization/Formatters/Binary/BinaryFormatter.cs

@@ -38,10 +38,10 @@ public BinaryFormatter(ISurrogateSelector? selector, StreamingContext context)
 
         public object Deserialize(Stream serializationStream)
         {
-            // don't refactor this check out into a helper method; linker will have difficulty pruning
+            // don't refactor the 'throw' into a helper method; linker will have difficulty trimming
             if (!SerializationInfo.BinaryFormatterEnabled)
             {
-                throw new NotSupportedException(SR.BinaryFormatter_SerializationDisallowed);
+                throw CreateBinaryFormatterDisallowedException();
             }
 
             if (serializationStream == null)
@@ -82,10 +82,10 @@ public object Deserialize(Stream serializationStream)
 
         public void Serialize(Stream serializationStream, object graph)
         {
-            // don't refactor this check out into a helper method; linker will have difficulty pruning
+            // don't refactor the 'throw' into a helper method; linker will have difficulty trimming
             if (!SerializationInfo.BinaryFormatterEnabled)
             {
-                throw new NotSupportedException(SR.BinaryFormatter_SerializationDisallowed);
+                throw CreateBinaryFormatterDisallowedException();
             }
 
             if (serializationStream == null)
@@ -112,5 +112,19 @@ internal static TypeInformation GetTypeInformation(Type type) =>
                 string assemblyName = FormatterServices.GetClrAssemblyName(t, out bool hasTypeForwardedFrom);
                 return new TypeInformation(FormatterServices.GetClrTypeFullName(t), assemblyName, hasTypeForwardedFrom);
             });
+
+        private static Exception CreateBinaryFormatterDisallowedException()
+        {
+            // If we're in an environment where BinaryFormatter never has a
+            // chance of succeeding, use PNSE. Otherwise use regular NSE.
+
+            string message = SR.BinaryFormatter_SerializationDisallowed;
+
+#if BINARYFORMATTER_PNSE
+            throw new PlatformNotSupportedException(message);
+#else
+            throw new NotSupportedException(message);
+#endif
+        }
     }
 }

src/libraries/System.Runtime.Serialization.Formatters/tests/DisableBitTests.cs

@@ -24,12 +24,12 @@ public static void DisabledAlwaysInBrowser()
 
             MemoryStream ms = new MemoryStream();
             BinaryFormatter bf = new BinaryFormatter();
-            var ex = Assert.Throws<NotSupportedException>(() => bf.Serialize(ms, "A string to serialize."));
+            var ex = Assert.Throws<PlatformNotSupportedException>(() => bf.Serialize(ms, "A string to serialize."));
             Assert.Contains(MoreInfoUrl, ex.Message, StringComparison.Ordinal); // error message should link to the more info URL
 
             // Then test deserialization
 
-            ex = Assert.Throws<NotSupportedException>(() => bf.Deserialize(ms));
+            ex = Assert.Throws<PlatformNotSupportedException>(() => bf.Deserialize(ms));
             Assert.Contains(MoreInfoUrl, ex.Message, StringComparison.Ordinal); // error message should link to the more info URL
         }