Add compatibility checks for rb_profile_frames.

On ruby < 3.0 rb_profile_frames omits c frames so we cannot use it to get frame_depth.
On ruby < 3.2.0 it adds an extra dummy frame in the output that must be accounted for.

Author: WillHalto

ext/debug/debug.c

@@ -89,6 +89,7 @@ capture_frames(VALUE self, VALUE skip_path_prefix)
     return rb_debug_inspector_open(di_body, (void *)skip_path_prefix);
 }
 
+#ifdef RB_PROFILE_FRAMES_HAS_C_FRAMES
 #define BUFF_SIZE 4096
 
 static VALUE
@@ -109,8 +110,21 @@ frame_depth(VALUE self)
 
     // rb_profile_frames will return one extra frame
     // https://bugs.ruby-lang.org/issues/18907
-    return INT2FIX(size - 1);
+        return INT2FIX(size - 1);
+    #else
+        return INT2FIX(size);
+    #endif  
+}
+#else
+static VALUE
+frame_depth(VALUE self)
+{
+    // TODO: more efficient API
+    VALUE bt = rb_make_backtrace();
+    return INT2FIX(RARRAY_LEN(bt));
 }
+#endif
 
 // iseq
 

ext/debug/extconf.rb

@@ -7,8 +7,16 @@
   $defs << '-DHAVE_RB_ISEQ_PARAMETERS'
   $defs << '-DHAVE_RB_ISEQ_CODE_LOCATION'
 
+  if RUBY_VERSION >= '3.0.0'
+    $defs << '-DRB_PROFILE_FRAMES_HAS_C_FRAMES'
+  end
+
   if RUBY_VERSION >= '3.1.0'
     $defs << '-DHAVE_RB_ISEQ_TYPE'
+
+    if RUBY_VERSION < '3.2.0'
+      $defs << '-DRB_PROFILE_FRAMES_HAS_EXTRA_FRAME'
+    end
   end
 else
   # not on MRI

test/console/control_flow_commands_test.rb

@@ -363,48 +363,50 @@ def test_next_steps_over_rescue_when_raising_from_method
   # Tests that next/finish work for a deep call stack.
   # We use different logic for computing frame depth when the call stack is above/below 4096.
   #
-  class DeepCallstackTest < ConsoleTestCase
-    def program
-      <<~RUBY
-         1| # target.rb
-         2| def foo
-         3|     "hello"
-         4| end
-         5|   
-         6| def recursive(n,stop)
-         7|   foo
-         8|   return if n >= stop
-         9| 
-        10|   recursive(n + 1, stop)
-        11| end
-        12| 
-        13| recursive(0, 4100)
-        14| 
-        15| "done"
-      RUBY
-    end
-    
-    def test_next
-      debug_code(program) do
-        type 'b 13'
-        type 'c'
-        assert_line_num 13
-        type 'n'
-        assert_line_num 15
-        type 'q!'
       end
-    end
-
-    def test_finish
-      debug_code(program) do
-        type 'b 13'
-        type 'c'
-        assert_line_num 13
-        type 's'
-        assert_line_num 7
-        type 'fin'
-        assert_line_num 11
-        type 'q!'
+      def test_finish
+        debug_code(program) do
+          type 'b 13'
+          type 'c'
+          assert_line_num 13
+          type 's'
+          assert_line_num 7
+          type 'fin'
+          assert_line_num 11
+          type 'q!'
+        end
       end
     end
   end