move skipping anonymous classes to the tracepoint, add struct to tests

ext/datadog_cov/datadog_cov.c

@@ -235,16 +235,6 @@ static int process_instantiated_klass(st_data_t key, st_data_t _value, st_data_t
     return ST_CONTINUE;
   }
 
-  // Skip anonymous classes starting with "#<Class".
-  // This small snippet improves performance for worst case by 20% for rubocop test suite: it allows
-  // us to skip the source location lookup that will always fail for anonymous classes.
-  const char *klass_name_ptr = RSTRING_PTR(klass_name);
-  const unsigned long klass_name_len = RSTRING_LEN(klass_name);
-  if (klass_name_len >= 2 && klass_name_ptr[0] == '#' && klass_name_ptr[1] == '<')
-  {
-    return ST_CONTINUE;
-  }
-
   VALUE source_location = safely_get_source_location(klass_name);
   if (source_location == Qnil || RARRAY_LEN(source_location) == 0)
   {
@@ -283,6 +273,14 @@ static void on_newobj_event(VALUE tracepoint_data, void *data)
   {
     return;
   }
+  // Skip anonymous classes starting with "#<Class".
+  // it allows us to skip the source location lookup that will always fail
+  const char *name = rb_obj_classname(new_object);
+  const unsigned long klass_name_len = strlen(name);
+  if (klass_name_len >= 2 && name[0] == '#' && name[1] == '<')
+  {
+    return;
+  }
 
   if (st_lookup(dd_cov_data->klasses_table, (st_data_t)klass, 0))
   {

spec/ddcov/app/model/my_struct.rb

@@ -0,0 +1 @@
+User = Struct.new(:name, :email)

spec/ddcov/ddcov_spec.rb

@@ -3,6 +3,7 @@
 require "datadog_cov.#{RUBY_VERSION}_#{RUBY_PLATFORM}"
 
 require_relative "app/model/my_model"
+require_relative "app/model/my_struct"
 require_relative "calculator/calculator"
 require_relative "calculator/code_with_❤️"
 
@@ -329,6 +330,7 @@ def thread_local_cov
           subject.start
 
           MyModel.new
+          User.new("john doe", "johndoe@mail.test")
           c = Class.new(Object) do
           end
           c.new
@@ -342,8 +344,9 @@ def thread_local_cov
           end
 
           coverage = subject.stop
-          expect(coverage.size).to eq(1)
+          expect(coverage.size).to eq(2)
           expect(coverage.keys).to include(absolute_path("app/model/my_model.rb"))
+          expect(coverage.keys).to include(absolute_path("app/model/my_struct.rb"))
         end
       end