[PATCH v4 2/8] GDB/Python: Use None for `var_zuinteger_unlimited' value set to `unlimited'

["Maciej W. Rozycki" <macro@embecosm.com>]

Consistently with the `var_integer' and `var_uinteger' parameters return 
the special value of None for a `var_zuinteger_unlimited' parameter set 
to `unlimited' by using the Py_RETURN_NONE macro in this case, fixing 
commit 0489430a0e1a ("Handle var_zuinteger and var_zuinteger_unlimited 
from Python"); cf. PR python/20084.  Adjust the testsuite accordingly. 
---
New change in v4.
---
 gdb/python/python.c                       |   10 +++++++++-
 gdb/testsuite/gdb.python/py-parameter.exp |    4 ++--
 2 files changed, 11 insertions(+), 3 deletions(-)

gdb-python-var-zuinteger-unlimited-none.diff
Index: src/gdb/python/python.c
===================================================================
--- src.orig/gdb/python/python.c
+++ src/gdb/python/python.c
@@ -512,9 +512,17 @@ gdbpy_parameter_value (const setting &va
 	Py_RETURN_NONE;
       /* Fall through.  */
     case var_zinteger:
-    case var_zuinteger_unlimited:
       return gdb_py_object_from_longest (var.get<int> ()).release ();
 
+    case var_zuinteger_unlimited:
+      {
+	int val = var.get<int> ();
+
+	if (val == -1)
+	  Py_RETURN_NONE;
+	return gdb_py_object_from_longest (val).release ();
+      }
+
     case var_uinteger:
       {
 	unsigned int val = var.get<unsigned int> ();
Index: src/gdb/testsuite/gdb.python/py-parameter.exp
===================================================================
--- src.orig/gdb/testsuite/gdb.python/py-parameter.exp
+++ src/gdb/testsuite/gdb.python/py-parameter.exp
@@ -343,8 +343,8 @@ proc_with_prefix test_integer_parameter
 	} elseif {$kind == "PARAM_ZUINTEGER_UNLIMITED"} {
 	    gdb_test_no_output "python test_param_$kind.value = -1" \
 		"check that PARAM_ZUINTEGER value can be set to -1"
-	    gdb_test "python print(gdb.parameter('test-$kind'))" "-1" \
-		"check that PARAM_ZUINTEGER value is -1 after setting"
+	    gdb_test "python print(gdb.parameter('test-$kind'))" "None" \
+		"check that PARAM_ZUINTEGER value is None after setting"
 	} else {
 	    error "invalid kind: $kind"
 	}