Add class cycle detection during unmarshaling (#946)

Add support for detection of class cycles during unmarshaling in
languages which do no have garbage collection: C++, Swift, and Objective-C.
A `MarshalException` is thrown when a cycle is detected.

The property `Ice.AcceptClassCycles` can be set to a value greater than `0`
to change this behavior.

3 files changed, 20 insertions, 0 deletions

diff --git a/ruby/src/IceRuby/Communicator.cpp b/ruby/src/IceRuby/Communicator.cpp
index 6050352e5d1..29f4f9e387e 100644
--- a/ruby/src/IceRuby/Communicator.cpp
+++ b/ruby/src/IceRuby/Communicator.cpp
@@ -207,6 +207,9 @@ IceRuby_initialize(int argc, VALUE* argv, VALUE /*self*/)
             data.properties = Ice::createProperties(seq, data.properties);
         }
 
+        // Always accept cycles in Ruby
+        data.properties->setProperty("Ice.AcceptClassCycles", "1");
+
         //
         // Remaining command line options are passed to the communicator
         // as an argument vector in case they contain plugin properties.
diff --git a/ruby/test/Ice/objects/AllTests.rb b/ruby/test/Ice/objects/AllTests.rb
index 65d1faa0fcf..1a01c9b5864 100644
--- a/ruby/test/Ice/objects/AllTests.rb
+++ b/ruby/test/Ice/objects/AllTests.rb
@@ -404,5 +404,19 @@ def allTests(helper, communicator)
         test(f32.f2.ice_getIdentity().name == "F22")
     end
     puts "ok"
+
+    print "testing sending class cycle... "
+    STDOUT.flush
+    rec = Test::Recursive.new
+    rec.v = rec
+    acceptsCycles = initial.acceptsClassCycles()
+    begin
+        initial.setCycle(rec)
+        test(acceptsCycles)
+    rescue Ice::UnknownLocalException => ex
+        test(!acceptsCycles)
+    end
+    puts "ok"
+
     return initial
 end
diff --git a/ruby/test/Ice/objects/Test.ice b/ruby/test/Ice/objects/Test.ice
index b4e0f3fd690..af4ab4786c9 100644
--- a/ruby/test/Ice/objects/Test.ice
+++ b/ruby/test/Ice/objects/Test.ice
@@ -186,6 +186,9 @@ class Initial
     void setRecursive(Recursive p);
     bool supportsClassGraphDepthMax();
 
+    void setCycle(Recursive r);
+    bool acceptsClassCycles();
+
     ["marshaled-result"] B getMB();
     ["amd", "marshaled-result"] B getAMDMB();