Make channels and calls properly mark references to their credentials

src/ruby/ext/grpc/rb_call.c

@@ -72,6 +72,10 @@ static ID id_cq;
  * the flags used to create metadata from a Hash */
 static ID id_flags;
 
+/* id_credentials is the name of the hidden ivar that preserves the value
+ * of the credentials added to the call */
+static ID id_credentials;
+
 /* id_input_md is the name of the hidden ivar that preserves the hash used to
  * create metadata, so that references to the strings it contains last as long
  * as the call the metadata is added to. */
@@ -299,6 +303,7 @@ static VALUE grpc_rb_call_set_credentials(VALUE self, VALUE credentials) {
              "grpc_call_set_credentials failed with %s (code=%d)",
              grpc_call_error_detail_of(err), err);
   }
+  rb_ivar_set(self, id_credentials, credentials);
   return Qnil;
 }
 
@@ -859,6 +864,7 @@ void Init_grpc_call() {
   id_cq = rb_intern("__cq");
   id_flags = rb_intern("__flags");
   id_input_md = rb_intern("__input_md");
+  id_credentials = rb_intern("__credentials");
 
   /* Ids used in constructing the batch result. */
   sym_send_message = ID2SYM(rb_intern("send_message"));

src/ruby/ext/grpc/rb_channel.c

@@ -70,11 +70,10 @@ static VALUE grpc_rb_cChannel = Qnil;
 /* Used during the conversion of a hash to channel args during channel setup */
 static VALUE grpc_rb_cChannelArgs;
 
-/* grpc_rb_channel wraps a grpc_channel.  It provides a peer ruby object,
- * 'mark' to minimize copying when a channel is created from ruby. */
+/* grpc_rb_channel wraps a grpc_channel. */
 typedef struct grpc_rb_channel {
-  /* Holder of ruby objects involved in constructing the channel */
-  VALUE mark;
+  VALUE credentials;
+
   /* The actual channel */
   grpc_channel *wrapped;
 } grpc_rb_channel;
@@ -87,13 +86,8 @@ static void grpc_rb_channel_free(void *p) {
   };
   ch = (grpc_rb_channel *)p;
 
-  /* Deletes the wrapped object if the mark object is Qnil, which indicates
-   * that no other object is the actual owner. */
-  if (ch->wrapped != NULL && ch->mark == Qnil) {
+  if (ch->wrapped != NULL) {
     grpc_channel_destroy(ch->wrapped);
-    rb_warning("channel gc: destroyed the c channel");
-  } else {
-    rb_warning("channel gc: did not destroy the c channel");
   }
 
   xfree(p);
@@ -106,8 +100,8 @@ static void grpc_rb_channel_mark(void *p) {
     return;
   }
   channel = (grpc_rb_channel *)p;
-  if (channel->mark != Qnil) {
-    rb_gc_mark(channel->mark);
+  if (channel->credentials != Qnil) {
+    rb_gc_mark(channel->credentials);
   }
 }
 
@@ -125,7 +119,7 @@ static rb_data_type_t grpc_channel_data_type = {
 static VALUE grpc_rb_channel_alloc(VALUE cls) {
   grpc_rb_channel *wrapper = ALLOC(grpc_rb_channel);
   wrapper->wrapped = NULL;
-  wrapper->mark = Qnil;
+  wrapper->credentials = Qnil;
   return TypedData_Wrap_Struct(cls, &grpc_channel_data_type, wrapper);
 }
 
@@ -162,6 +156,7 @@ static VALUE grpc_rb_channel_init(int argc, VALUE *argv, VALUE self) {
     }
     ch = grpc_insecure_channel_create(target_chars, &args, NULL);
   } else {
+    wrapper->credentials = credentials;
     creds = grpc_rb_get_wrapped_channel_credentials(credentials);
     ch = grpc_secure_channel_create(creds, target_chars, &args, NULL);
   }
@@ -330,7 +325,6 @@ static VALUE grpc_rb_channel_destroy(VALUE self) {
   if (ch != NULL) {
     grpc_channel_destroy(ch);
     wrapper->wrapped = NULL;
-    wrapper->mark = Qnil;
   }
 
   return Qnil;