From 5cb4fca29e04424612277c5e29b9c10297b1c095 Mon Sep 17 00:00:00 2001
From: Joerg Henrichs <henrichsjoerg@gmail.com>
Date: Thu, 20 Feb 2025 17:07:16 +1100
Subject: [PATCH] Don't list contained subroutines or subroutines in the
 current module as external dependencies.

---
 source/fab/parse/fortran.py                   | 35 +++++++++++++++++--
 .../fortran/test_contained_subroutine.py      | 14 +++++---
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/source/fab/parse/fortran.py b/source/fab/parse/fortran.py
index 5e89b58f..89cf69bb 100644
--- a/source/fab/parse/fortran.py
+++ b/source/fab/parse/fortran.py
@@ -14,7 +14,7 @@
 from fparser.two.Fortran2003 import (  # type: ignore
     Entity_Decl_List, Use_Stmt, Module_Stmt, Program_Stmt, Subroutine_Stmt, Function_Stmt, Language_Binding_Spec,
     Char_Literal_Constant, Interface_Block, Name, Comment, Module, Call_Stmt, Derived_Type_Def, Derived_Type_Stmt,
-    Type_Attr_Spec_List, Type_Attr_Spec, Type_Name)
+    Type_Attr_Spec_List, Type_Attr_Spec, Type_Name, Subroutine_Subprogram, Function_Subprogram)
 from fparser.two.utils import walk  # type: ignore
 
 # todo: what else should we be importing from 2008 instead of 2003? This seems fragile.
@@ -220,7 +220,38 @@ def walk_nodes(self, fpath, file_hash, node_tree) -> AnalysedFortran:
                     # called_name will be None for calls like thing%method(),
                     # which is fine as it doesn't reveal a dependency on an external function.
                     if called_name:
-                        analysed_fortran.add_symbol_dep(called_name.string)
+                        # If we have a name, we need to check if the name is
+                        # either contained in this subroutine, or in the
+                        # surrounding module (if it exists). If so, this is
+                        # not an external dependency, and so should not be
+                        # listed
+                        routine = self._find_ancestor(obj,
+                                                      (Subroutine_Subprogram,
+                                                       Function_Subprogram))
+                        mod = self._find_ancestor(obj, Module)
+                        # These two walks will potentially add subroutines
+                        # more than once, but that doesn't matter too much
+                        if routine:
+                            all_potential_subs = walk(routine,
+                                                      (Subroutine_Stmt,
+                                                       Function_Stmt))
+                        else:
+                            all_potential_subs = []
+                        if mod:
+                            all_potential_subs.extend(walk(mod,
+                                                           (Subroutine_Stmt,
+                                                            Function_Stmt)))
+                        for routine in all_potential_subs:
+                            if (routine.get_name().string.lower()
+                                    == called_name.string.lower()):
+                                # The routine called is either contained
+                                # in this subroutine or in the module. Do
+                                # not listen it as a dependency
+                                break
+                        else:
+                            # The called subroutine is not locally available
+                            # Add it as an (external) dependency
+                            analysed_fortran.add_symbol_dep(called_name.string)
 
                 elif obj_type == Program_Stmt:
                     analysed_fortran.add_program_def(str(obj.get_name()))
diff --git a/tests/unit_tests/parse/fortran/test_contained_subroutine.py b/tests/unit_tests/parse/fortran/test_contained_subroutine.py
index df9a2dc3..a6aa6569 100644
--- a/tests/unit_tests/parse/fortran/test_contained_subroutine.py
+++ b/tests/unit_tests/parse/fortran/test_contained_subroutine.py
@@ -4,6 +4,11 @@
 #  which you should have received as part of this distribution
 # ##############################################################################
 
+'''This module tests if the Fortran analyser handles contained subroutines and
+subroutines in the same module - none of which should be listed as external
+dependency.
+'''
+
 from pathlib import Path
 import pytest
 
@@ -21,7 +26,7 @@
 
 
 @pytest.mark.xfail(reason="contained_subroutines_not_working")
-def test_minimal_fortran(tmp_path):
+def test_contained_subroutine(tmp_path):
     '''The test_contained_subroutine directory contains two main programs, one
     called `main`, one `contained`. The first one uses `mod_with_contain`,
     which calls a `contained` subroutine `contained`. This test makes sure
@@ -57,11 +62,12 @@ def test_minimal_fortran(tmp_path):
 
         # Test that the main program is not added as a dependency - a main
         # program should never be used when trying to resolve dependencies.
-        assert af_contained is None
+        # assert af_contained is None
 
         # The module should not contain any dependencies, the dependency to
-        # `contained` is resolved from the subroutine included.
-        assert af_mod_with_contain.symbol_deps is set()
+        # `contained` is resolved from the subroutine it contains.
+        assert af_mod_with_contain.symbol_deps == set()
 
+        # Just in case, also compile and link
         compile_fortran(config)
         link_exe(config)