Change the way provided LKQL rule files are resolved

When provide through the CLI, an LKQL rule file is resolved relatively
to the current working dir.
When provided through a GPR file, an LKQL rule file is resolved
relatively to this project file.

Author: HugoGGuerrier

lkql_checker/doc/gnatcheck_rm/using_gnatcheck.rst

@@ -184,7 +184,8 @@ The following switches control the general ``gnatcheck`` behavior
 
 ``--rule-file=filename``
   Load the given file as an LKQL rule options file (see :ref:`LKQL_options_file`
-  for more information).
+  for more information). If not absolute, the provided path is relative to the
+  current working directory.
 
   .. index:: -r, --rule
 
@@ -352,9 +353,9 @@ GNATcheck:
   defining this attribute, then, values are concatenated.
 
 ``Rule_File``
-  Value is a path to a LKQL rule file. The path is relative to the project
-  file that defines this attribute. See :ref:`LKQL_options_file` for more
-  information.
+  Value is a path to a LKQL rule file. If not absolute, the path is relative
+  to the project file that defines this attribute.
+  See :ref:`LKQL_options_file` for more information.
 
   If the ``--rule-file`` switch is set when calling ``gnatcheck`` on a project
   file defining this attribute, then, an error is emitted and ``gnatcheck``

lkql_checker/src/gnatcheck-options.ads

@@ -214,7 +214,8 @@ package Gnatcheck.Options is
    --  processed, keeps the name of this file, otherwise is null.
 
    LKQL_Rule_File_Name : Unbounded_String := Null_Unbounded_String;
-   --  Name of the LKQL file to process as a rule file.
+   --  Name of the LKQL file to process as a rule file. We assume that the
+   --  stored value is an absolute path to the LKQL rule file.
 
    ---------------------
    -- Project support --

lkql_checker/src/gnatcheck-projects.adb

@@ -261,14 +261,12 @@ package body Gnatcheck.Projects is
       end if;
 
       --  Process the LKQL rule file
-      --  Process the rule list
       if Proj.Has_Attribute (Rule_File_Attr) then
          declare
             Rule_File : constant String :=
               Load_Single_Attribute (Rule_File_Attr);
          begin
-            Set_LKQL_Rule_File
-              (My_Project.Get_Project_Relative_File (Rule_File));
+            Set_LKQL_Rule_File (Rule_File, True);
          end;
       end if;
 
@@ -1111,11 +1109,19 @@ package body Gnatcheck.Projects is
    -- Set_LKQL_Rule_File --
    ------------------------
 
-   procedure Set_LKQL_Rule_File (File : String) is
+   procedure Set_LKQL_Rule_File (File : String; Project_Relative : Boolean) is
       use Ada.Strings.Unbounded;
+
+      Resolved_File : constant String :=
+        (if Is_Absolute_Path (File)
+         then File
+         else
+           (if Project_Relative
+            then Gnatcheck_Prj.Get_Project_Relative_File (File)
+            else Normalize_Pathname (File)));
    begin
       if LKQL_Rule_File_Name = Null_Unbounded_String then
-         LKQL_Rule_File_Name := To_Unbounded_String (File);
+         LKQL_Rule_File_Name := To_Unbounded_String (Resolved_File);
       else
          Error ("only one LKQL configuration file is allowed");
          Rule_Option_Problem_Detected := True;

lkql_checker/src/gnatcheck-projects.ads

@@ -255,9 +255,15 @@ package Gnatcheck.Projects is
    --  Use ``Add_Rule_Option`` to forge a new rule option enabling the given
    --  rule without any parameter.
 
-   procedure Set_LKQL_Rule_File (File : String);
+   procedure Set_LKQL_Rule_File (File : String; Project_Relative : Boolean);
    --  Set the given ``File`` as the LKQL rule file to process during the
-   --  execution of ``Process_Rule_Options``.
+   --  execution of ``Process_Rule_Options``. If a rule file has already been
+   --  set, this function displays an error and set the
+   --  ``Rule_Option_Problem_Detected`` flag to True.
+   --  If the provided ``File`` isn't an absolute path, if ``Project_Relative``
+   --  is set to ``True``, resolve the provided file relatively to
+   --  the current project file (if any). Else, resolve ``File`` relatively to
+   --  the current working directory.
 
    function Is_Rule_Options_Empty return Boolean;
    --  Get whether the rule options are empty.

lkql_checker/src/gnatcheck-rules-rule_table.adb

@@ -804,8 +804,6 @@ package body Gnatcheck.Rules.Rule_Table is
 
    procedure Process_LKQL_Rule_File (LKQL_RF_Name : String)
    is
-      Rule_File_Absolute_Path : constant String :=
-        Get_Rule_File_Name (LKQL_RF_Name);
       JSON_Config_File_Name : constant String :=
         Global_Report_Dir.all & "gnatcheck-rules.json.out";
       Parser_Pid : Process_Id;
@@ -823,21 +821,21 @@ package body Gnatcheck.Rules.Rule_Table is
          Instance_Object : JSON_Value) is
       begin
          Process_Rule_Object
-           (Rule_File_Absolute_Path, String (Instance_Id), Instance_Object);
+           (LKQL_RF_Name, String (Instance_Id), Instance_Object);
       end Rule_Object_Mapper;
 
    begin
       --  Ensure that the provided rule file exists
-      if not Is_Regular_File (Rule_File_Absolute_Path) then
-         Error ("can not locate LKQL rule file " & Rule_File_Absolute_Path);
+      if not Is_Regular_File (LKQL_RF_Name) then
+         Error ("can not locate LKQL rule file " & LKQL_RF_Name);
          Missing_Rule_File_Detected := True;
          return;
       end if;
 
       --  Call the LKQL rule config file parser and parse its result
       Parser_Pid :=
         Spawn_LKQL_Rule_File_Parser
-          (Rule_File_Absolute_Path, JSON_Config_File_Name);
+          (LKQL_RF_Name, JSON_Config_File_Name);
       Wait_Process (Waited_Pid, Success);
 
       if Parser_Pid /= Waited_Pid or else not Success then

lkql_checker/src/gnatcheck_main.adb

@@ -503,7 +503,7 @@ begin
 
    --  Add the command-line LKQL rule file to the rule options
    if Arg.Rule_File.Get /= Null_Unbounded_String then
-      Set_LKQL_Rule_File (To_String (Arg.Rule_File.Get));
+      Set_LKQL_Rule_File (To_String (Arg.Rule_File.Get), False);
    end if;
 
    --  Get the default LKQL rule file if none has been specified
@@ -512,7 +512,9 @@ begin
          Def_LKQL : constant String := Default_LKQL_Rule_Options_File;
       begin
          if Is_Regular_File (Def_LKQL) then
-            Set_LKQL_Rule_File (Def_LKQL);
+            --  The default rule file is already resolved relatively to the
+            --  current project file.
+            Set_LKQL_Rule_File (Def_LKQL, False);
          end if;
       end;
    end if;

testsuite/tests/gnatcheck/lkql_rule_file_resolution/prj/main.adb

@@ -0,0 +1,8 @@
+procedure Main is
+begin
+   goto lbl;  --  FLAG
+   <<lbl>>
+
+   null;
+   null;  --  FLAG
+end Main;

testsuite/tests/gnatcheck/lkql_rule_file_resolution/prj/prj_rules.lkql

@@ -0,0 +1,3 @@
+val rules = @{
+    redundant_null_statements
+}

testsuite/tests/gnatcheck/lkql_rule_file_resolution/prj/with_invalid.gpr

@@ -0,0 +1,5 @@
+project With_Invalid is
+   package Check is
+      for Rule_File use "rules.lkql";
+   end Check;
+end With_Invalid;

testsuite/tests/gnatcheck/lkql_rule_file_resolution/prj/with_valid.gpr

@@ -0,0 +1,5 @@
+project With_Valid is
+   package Check is
+      for Rule_File use "prj_rules.lkql";
+   end Check;
+end With_Valid;