ada_api/unparsing: renumber ids instead of removing them

Future work will add support for group Ids to the unparsing framework.
Proper testing for this feature will require ids to be visible in the
baseline: stop removing ids from the test output and instead renumber
them to avoid the issue for which removing ids was a workaround.

Author: pmderodat

testsuite/tests/ada_api/unparsing/commands.adb

@@ -1,3 +1,4 @@
+with Ada.Containers.Ordered_Maps;
 with Ada.Strings.Unbounded;    use Ada.Strings.Unbounded;
 with Ada.Text_IO;              use Ada.Text_IO;
 with Ada.Text_IO.Unbounded_IO; use Ada.Text_IO.Unbounded_IO;
@@ -19,7 +20,11 @@ procedure Commands is
    Context : constant Lk_Context := Create_Context (Self_Id);
 
    procedure Check (Filename : String; Buffer : String := "var i: Int = 0;");
-   procedure Remove_Ids (Value : JSON_Value);
+
+   procedure Reset_Ids (Value : JSON_Value);
+   --  Ids in prettier are generated with a process-wide counter. To avoid
+   --  interference between tests, we use this procedure to renumber Ids for a
+   --  given document.
 
    -----------
    -- Check --
@@ -58,19 +63,26 @@ procedure Commands is
       --  Remove "id" fields from the JSON representation, for output stability
 
       JSON := GNATCOLL.JSON.Read (JSON_Text);
-      Remove_Ids (JSON);
+      Reset_Ids (JSON);
 
       JSON_Text := JSON.Write (Compact => False);
       Put_Line (JSON_Text);
       New_Line;
    end Check;
 
-   ----------------
-   -- Remove_Ids --
-   ----------------
+   ---------------
+   -- Reset_Ids --
+   ---------------
+
+   procedure Reset_Ids (Value : JSON_Value) is
+
+      package Id_Maps is new Ada.Containers.Ordered_Maps
+        (Key_Type => Integer, Element_Type => Integer);
+      Id_Map : Id_Maps.Map;
 
-   procedure Remove_Ids (Value : JSON_Value) is
       procedure Process (Name : String; Value : JSON_Value);
+      procedure Renumber (Object : JSON_Value; Name : String);
+      procedure Recurse (Value : JSON_Value);
 
       -------------
       -- Process --
@@ -79,25 +91,60 @@ procedure Commands is
       procedure Process (Name : String; Value : JSON_Value) is
          pragma Unreferenced (Name);
       begin
-         Remove_Ids (Value);
+         Recurse (Value);
       end Process;
+
+      --------------
+      -- Renumber --
+      --------------
+
+      procedure Renumber (Object : JSON_Value; Name : String) is
+      begin
+         if Object.Has_Field (Name) then
+            declare
+               Old_Id : constant Integer := Object.Get (Name);
+               New_Id : Integer;
+            begin
+               if Old_Id = 0 then
+                  Object.Unset_Field (Name);
+               else
+                  if Id_Map.Contains (Old_Id) then
+                     New_Id := Id_Map.Element (Old_Id);
+                  else
+                     New_Id := Integer (Id_Map.Length) + 1;
+                     Id_Map.Insert (Old_Id, New_Id);
+                  end if;
+                  Object.Set_Field (Name, New_Id);
+               end if;
+            end;
+         end if;
+      end Renumber;
+
+      -------------
+      -- Recurse --
+      -------------
+
+      procedure Recurse (Value : JSON_Value) is
+      begin
+         case Value.Kind is
+            when JSON_Object_Type =>
+               Renumber (Value, "id");
+               Renumber (Value, "ifBreakGroupId");
+               Value.Map_JSON_Object (Process'Access);
+
+            when JSON_Array_Type =>
+               for V of JSON_Array'(Value.Get) loop
+                  Recurse (V);
+               end loop;
+
+            when others =>
+               return;
+         end case;
+      end Recurse;
+
    begin
-      case Value.Kind is
-         when JSON_Object_Type =>
-            if Value.Has_Field ("id") then
-               Value.Unset_Field ("id");
-            end if;
-            Value.Map_JSON_Object (Process'Access);
-
-         when JSON_Array_Type =>
-            for V of JSON_Array'(Value.Get) loop
-               Remove_Ids (V);
-            end loop;
-
-         when others =>
-            return;
-      end case;
-   end Remove_Ids;
+      Recurse (Value);
+   end Reset_Ids;
 
 begin
    Check ("cmd_align.json");