Fix PyUnicode_FromFormat %c specifier

Fixes #252

Author: msimacek

graalpython/com.oracle.graal.python.test/src/tests/cpyext/test_unicode.py

@@ -214,6 +214,19 @@ def compile_module(self, name):
         cmpfunc=unhandled_error_compare
     )
 
+    test_PyUnicode_FromFormat_c = CPyExtFunction(
+        _reference_fromformat,
+        lambda: (
+            ("char %c\n", ord('x')),
+            ("char %c\n", ord('あ')),
+        ),
+        resultspec="O",
+        argspec='si',
+        arguments=["char* fmt", "int c"],
+        callfunction="PyUnicode_FromFormat",
+        cmpfunc=unhandled_error_compare
+    )
+
     test_PyUnicode_FromFormat4 = CPyExtFunction(
         _reference_fromformat,
         lambda: (

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/capi/CExtNodes.java

@@ -96,7 +96,6 @@
 import com.oracle.graal.python.builtins.objects.cext.capi.CExtNodesFactory.TransformExceptionToNativeNodeGen;
 import com.oracle.graal.python.builtins.objects.cext.capi.CExtNodesFactory.VoidPtrToJavaNodeGen;
 import com.oracle.graal.python.builtins.objects.cext.capi.DynamicObjectNativeWrapper.PrimitiveNativeWrapper;
-import com.oracle.graal.python.builtins.objects.cext.capi.DynamicObjectNativeWrapper.PythonObjectNativeWrapper;
 import com.oracle.graal.python.builtins.objects.cext.capi.DynamicObjectNativeWrapper.WriteNativeMemberNode;
 import com.oracle.graal.python.builtins.objects.cext.capi.ExternalFunctionNodes.DefaultCheckFunctionResultNode;
 import com.oracle.graal.python.builtins.objects.cext.capi.ExternalFunctionNodes.MethKeywordsRoot;
@@ -107,6 +106,7 @@
 import com.oracle.graal.python.builtins.objects.cext.capi.NativeReferenceCache.ResolveNativeReferenceNode;
 import com.oracle.graal.python.builtins.objects.cext.capi.PGetDynamicTypeNode.GetSulongTypeNode;
 import com.oracle.graal.python.builtins.objects.cext.capi.PyTruffleObjectFree.FreeNode;
+import com.oracle.graal.python.builtins.objects.cext.capi.DynamicObjectNativeWrapper.PythonObjectNativeWrapper;
 import com.oracle.graal.python.builtins.objects.cext.common.CArrayWrappers.CArrayWrapper;
 import com.oracle.graal.python.builtins.objects.cext.common.CArrayWrappers.CByteArrayWrapper;
 import com.oracle.graal.python.builtins.objects.cext.common.CArrayWrappers.CStringWrapper;
@@ -3367,6 +3367,8 @@ Object doGeneric(String format, Object vaList) {
                                 throw raiseNode.raise(PythonBuiltinClassType.OverflowError, "character argument not in range(0x110000)");
                             }
                             result.append((char) ordinal);
+                            vaArgIdx++;
+                            valid = true;
                             break;
                         case 'd':
                         case 'i':