libdrgn/python: remove Type == operator

The == operator on drgn.Type is only intended for testing. It's
expensive and slow and not what people usually want. It's going to get
even more awkward to define once types can refer to objects (for
template parameters and static members and such). Let's replace == with
a new identical() function only available in unit tests. Then, remove
the operator from the Python bindings as well as the underlying libdrgn
drgn_type_eq() and drgn_qualified_type_eq() functions.

Signed-off-by: Omar Sandoval <osandov@osandov.com>

Author: osandov

_drgn.pyi

@@ -1466,14 +1466,6 @@ class Type:
 
     This class cannot be constructed directly. Instead, use one of the
     :ref:`api-type-constructors`.
-
-    .. note::
-
-        ``Type`` objects can be compared with ``==``. However, this is mostly
-        intended for testing and should not be used for type checking, as it
-        does a deep comparison that checks that the type definitions are
-        exactly the same, which is potentially time-consuming and
-        memory-intensive.
     """
 
     prog: Program

libdrgn/drgn.h.in

@@ -908,35 +908,6 @@ static inline struct drgn_error *drgn_type_has_member(struct drgn_type *type,
 					ret);
 }
 
-/**
- * Compare two @ref drgn_type%s for equality.
- *
- * Two types are equal if all of their fields are equal, recursively.
- *
- * @param[in] a First type.
- * @param[in] b First type.
- * @param[out] ret @c true if the types are equal, @c false if they are not.
- * @return @c NULL on success, non-@c NULL on error.
- */
-struct drgn_error *drgn_type_eq(struct drgn_type *a, struct drgn_type *b,
-				bool *ret);
-
-/**
- * Compare two @ref drgn_qualified_type%s for equality.
- *
- * Two qualified types are equal if their unqualified types are equal and their
- * qualifiers are equal.
- *
- * @param[in] a First qualified type.
- * @param[in] b First qualified type.
- * @param[out] ret @c true if the qualified types are equal, @c false if they
- * are not.
- * @return @c NULL on success, non-@c NULL on error.
- */
-struct drgn_error *drgn_qualified_type_eq(struct drgn_qualified_type a,
-					  struct drgn_qualified_type b,
-					  bool *ret);
-
 /**
  * Format the name of a type as a string.
  *

libdrgn/python/type.c

@@ -735,29 +735,6 @@ static PyObject *DrgnType_has_member(DrgnType *self, PyObject *args,
 		Py_RETURN_FALSE;
 }
 
-static PyObject *DrgnType_richcompare(DrgnType *self, PyObject *other, int op)
-{
-	if (!PyObject_TypeCheck(other, &DrgnType_type) ||
-	    (op != Py_EQ && op != Py_NE))
-		Py_RETURN_NOTIMPLEMENTED;
-
-	bool clear = set_drgn_in_python();
-	bool ret;
-	struct drgn_error *err = drgn_qualified_type_eq(DrgnType_unwrap(self),
-							DrgnType_unwrap((DrgnType *)other),
-							&ret);
-	if (clear)
-		clear_drgn_in_python();
-	if (err)
-		return set_drgn_error(err);
-	if (op == Py_NE)
-		ret = !ret;
-	if (ret)
-		Py_RETURN_TRUE;
-	else
-		Py_RETURN_FALSE;
-}
-
 static PyMethodDef DrgnType_methods[] = {
 	{"type_name", (PyCFunction)DrgnType_type_name, METH_NOARGS,
 	 drgn_Type_type_name_DOC},
@@ -785,7 +762,6 @@ PyTypeObject DrgnType_type = {
 	.tp_doc = drgn_Type_DOC,
 	.tp_traverse = (traverseproc)DrgnType_traverse,
 	.tp_clear = (inquiry)DrgnType_clear,
-	.tp_richcompare = (richcmpfunc)DrgnType_richcompare,
 	.tp_methods = DrgnType_methods,
 	.tp_getset = DrgnType_getset,
 };
@@ -1050,41 +1026,6 @@ static PyObject *TypeMember_repr(TypeMember *self)
 	}
 }
 
-static PyObject *TypeMember_richcompare(TypeMember *self, TypeMember *other,
-					int op)
-{
-	DrgnType *self_type, *other_type;
-	PyObject *self_key, *other_key, *ret;
-
-	if ((op != Py_EQ && op != Py_NE) ||
-	    !PyObject_TypeCheck((PyObject *)other, &TypeMember_type))
-		Py_RETURN_NOTIMPLEMENTED;
-
-	self_type = LazyType_get_borrowed((LazyType *)self);
-	if (!self_type)
-		return NULL;
-	other_type = LazyType_get_borrowed((LazyType *)other);
-	if (!other_type)
-		return NULL;
-
-	self_key = Py_BuildValue("OOOO", self_type, self->name,
-				 self->bit_offset, self->bit_field_size);
-	if (!self_key)
-		return NULL;
-
-	other_key = Py_BuildValue("OOOO", other_type, other->name,
-				  other->bit_offset, other->bit_field_size);
-	if (!other_key) {
-		Py_DECREF(self_key);
-		return NULL;
-	}
-
-	ret = PyObject_RichCompare(self_key, other_key, op);
-	Py_DECREF(other_key);
-	Py_DECREF(self_key);
-	return ret;
-}
-
 static PyMemberDef TypeMember_members[] = {
 	{"name", T_OBJECT, offsetof(TypeMember, name), READONLY,
 	 drgn_TypeMember_name_DOC},
@@ -1110,7 +1051,6 @@ PyTypeObject TypeMember_type = {
 	.tp_repr = (reprfunc)TypeMember_repr,
 	.tp_flags = Py_TPFLAGS_DEFAULT,
 	.tp_doc = drgn_TypeMember_DOC,
-	.tp_richcompare = (richcmpfunc)TypeMember_richcompare,
 	.tp_members = TypeMember_members,
 	.tp_getset = TypeMember_getset,
 	.tp_new = (newfunc)TypeMember_new,
@@ -1171,39 +1111,6 @@ static PyObject *TypeParameter_repr(TypeParameter *self)
 				    self->name);
 }
 
-static PyObject *TypeParameter_richcompare(TypeParameter *self, TypeParameter *other,
-					int op)
-{
-	DrgnType *self_type, *other_type;
-	PyObject *self_key, *other_key, *ret;
-
-	if ((op != Py_EQ && op != Py_NE) ||
-	    !PyObject_TypeCheck((PyObject *)other, &TypeParameter_type))
-		Py_RETURN_NOTIMPLEMENTED;
-
-	self_type = LazyType_get_borrowed((LazyType *)self);
-	if (!self_type)
-		return NULL;
-	other_type = LazyType_get_borrowed((LazyType *)other);
-	if (!other_type)
-		return NULL;
-
-	self_key = Py_BuildValue("OO", self_type, self->name);
-	if (!self_key)
-		return NULL;
-
-	other_key = Py_BuildValue("OO", other_type, other->name);
-	if (!other_key) {
-		Py_DECREF(self_key);
-		return NULL;
-	}
-
-	ret = PyObject_RichCompare(self_key, other_key, op);
-	Py_DECREF(other_key);
-	Py_DECREF(self_key);
-	return ret;
-}
-
 static PyMemberDef TypeParameter_members[] = {
 	{"name", T_OBJECT, offsetof(TypeParameter, name), READONLY,
 	 drgn_TypeParameter_name_DOC},
@@ -1223,7 +1130,6 @@ PyTypeObject TypeParameter_type = {
 	.tp_repr = (reprfunc)TypeParameter_repr,
 	.tp_flags = Py_TPFLAGS_DEFAULT,
 	.tp_doc = drgn_TypeParameter_DOC,
-	.tp_richcompare = (richcmpfunc)TypeParameter_richcompare,
 	.tp_members = TypeParameter_members,
 	.tp_getset = TypeParameter_getset,
 	.tp_new = (newfunc)TypeParameter_new,