gdb/python: missing PyObject_IsTrue error check in micmdpy_set_installed

Like the previous commit, I discovered that in micmdpy_set_installed
we were calling PyObject_IsTrue, but not checking for a possible error
value being returned.

The micmdpy_set_installed function implements the
gdb.MICommand.installed attribute, and the documentation indicates that
this attribute should only be assigned a bool:

  This attribute is read-write, setting this attribute to 'False'
  will uninstall the command, removing it from the set of available
  commands.  Setting this attribute to 'True' will install the
  command for use.

So I propose that instead of using PyObject_IsTrue we use
PyBool_Check, and if the new value fails this check we raise an
error.  We can then compare the new value to Py_True directly instead
of calling PyObject_IsTrue.

This is a potentially breaking change to the Python API, but hopefully
this will not impact too many people, and the fix is pretty
easy (switch to using a bool).  I've added a NEWS entry to draw
attention to this change.

Approved-By: Tom Tromey <tom@tromey.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/gdb/python/py-micmd.c b/gdb/python/py-micmd.c
index f4abf2b..e051b90 100644
--- a/gdb/python/py-micmd.c
+++ b/gdb/python/py-micmd.c
@@ -509,7 +509,16 @@ micmdpy_set_installed (PyObject *self, PyObject *newvalue, void *closure)
 {
   struct micmdpy_object *micmd_obj = (struct micmdpy_object *) self;
 
-  bool installed_p = PyObject_IsTrue (newvalue);
+  if (!PyBool_Check (newvalue))
+    {
+      PyErr_Format (PyExc_TypeError,
+		    _("gdb.MICommand.installed must be set to a bool, not %s"),
+		    newvalue == Py_None ? "None" : Py_TYPE(newvalue)->tp_name);
+      return -1;
+    }
+
+  bool installed_p = newvalue == Py_True;
+
   if (installed_p == (micmd_obj->mi_command != nullptr))
     return 0;