check Python c-api error code

Author: cpunion

dict.go

@@ -18,9 +18,7 @@ func newDict(obj *PyObject) Dict {
 }
 
 func DictFromPairs(pairs ...any) Dict {
-	if len(pairs)%2 != 0 {
-		panic("DictFromPairs requires an even number of arguments")
-	}
+	check(len(pairs)%2 == 0, "DictFromPairs requires an even number of arguments")
 	dict := newDict(C.PyDict_New())
 	for i := 0; i < len(pairs); i += 2 {
 		key := From(pairs[i])
@@ -62,9 +60,7 @@ func (d Dict) SetString(key string, value Objecter) {
 	ckey := AllocCStr(key)
 	r := C.PyDict_SetItemString(d.obj, ckey, valueObj)
 	C.free(unsafe.Pointer(ckey))
-	if r != 0 {
-		panic(fmt.Errorf("failed to set item string: %v", r))
-	}
+	check(r == 0, fmt.Sprintf("failed to set item string: %v", r))
 }
 
 func (d Dict) GetString(key string) Object {
@@ -81,9 +77,7 @@ func (d Dict) Del(key Objecter) {
 
 func (d Dict) ForEach(fn func(key, value Object)) {
 	items := C.PyDict_Items(d.obj)
-	if items == nil {
-		panic(fmt.Errorf("failed to get items of dict"))
-	}
+	check(items != nil, "failed to get items of dict")
 	defer C.Py_DecRef(items)
 	iter := C.PyObject_GetIter(items)
 	for {

function.go

@@ -74,7 +74,8 @@ func (f Func) Call(args ...any) Object {
 		for i, arg := range args {
 			obj := From(arg).Obj()
 			C.Py_IncRef(obj)
-			C.PyTuple_SetItem(argsTuple, C.Py_ssize_t(i), obj)
+			r := C.PyTuple_SetItem(argsTuple, C.Py_ssize_t(i), obj)
+			check(r == 0, fmt.Sprintf("failed to set item %d in tuple", i))
 		}
 		return newObject(C.PyObject_CallObject(f.obj, argsTuple))
 	}
@@ -471,9 +472,7 @@ func getMembers(t reflect.Type, methods map[uint]*slotMeta) (members *C.PyMember
 func AddType[T any](m Module, init any, name string, doc string) Object {
 	wrapper := wrapperType[T]{}
 	ty := reflect.TypeOf(wrapper.v)
-	if ty.Kind() != reflect.Struct {
-		panic("AddType: t must be a struct")
-	}
+	check(ty.Kind() == reflect.Struct, "AddType: t must be a struct")
 
 	meta := &typeMeta{
 		typ:     ty,
@@ -517,27 +516,21 @@ func AddType[T any](m Module, init any, name string, doc string) Object {
 	}
 
 	typeObj := C.PyType_FromSpec(spec)
-	if typeObj == nil {
-		panic(fmt.Sprintf("Failed to create type %s", name))
-	}
+	check(typeObj != nil, fmt.Sprintf("Failed to create type %s", name))
 
 	typeMetaMap[typeObj] = meta
 	pyTypeMap[ty] = typeObj
 
-	if C.PyModule_AddObject(m.obj, C.CString(name), typeObj) < 0 {
-		C.Py_DecRef(typeObj)
-		panic(fmt.Sprintf("Failed to add type %s to module", name))
-	}
+	r := C.PyModule_AddObjectRef(m.obj, C.CString(name), typeObj)
+	check(r == 0, fmt.Sprintf("Failed to add type %s to module", name))
 
 	return newObject(typeObj)
 }
 
 func (m Module) AddMethod(name string, fn any, doc string) Func {
 	v := reflect.ValueOf(fn)
 	t := v.Type()
-	if t.Kind() != reflect.Func {
-		panic("AddFunction: fn must be a function")
-	}
+	check(t.Kind() == reflect.Func, "AddFunction: fn must be a function")
 
 	if name == "" {
 		name = runtime.FuncForPC(v.Pointer()).Name()
@@ -583,14 +576,10 @@ func (m Module) AddMethod(name string, fn any, doc string) Func {
 	}
 
 	pyFunc := C.PyCFunction_New(def, m.obj)
-	if pyFunc == nil {
-		panic(fmt.Sprintf("Failed to create function %s", name))
-	}
+	check(pyFunc != nil, fmt.Sprintf("Failed to create function %s", name))
 
-	if C.PyModule_AddObject(m.obj, cName, pyFunc) < 0 {
-		C.Py_DecRef(pyFunc)
-		panic(fmt.Sprintf("Failed to add function %s to module", name))
-	}
+	r := C.PyModule_AddObjectRef(m.obj, cName, pyFunc)
+	check(r == 0, fmt.Sprintf("Failed to add function %s to module", name))
 
 	return newFunc(pyFunc)
 }

list.go

@@ -4,6 +4,7 @@ package gp
 #include <Python.h>
 */
 import "C"
+import "fmt"
 
 type List struct {
 	Object
@@ -31,13 +32,15 @@ func (l List) GetItem(index int) Object {
 func (l List) SetItem(index int, item Objecter) {
 	itemObj := item.Obj()
 	C.Py_IncRef(itemObj)
-	C.PyList_SetItem(l.obj, C.Py_ssize_t(index), itemObj)
+	r := C.PyList_SetItem(l.obj, C.Py_ssize_t(index), itemObj)
+	check(r == 0, fmt.Sprintf("failed to set item %d in list", index))
 }
 
 func (l List) Len() int {
 	return int(C.PyList_Size(l.obj))
 }
 
 func (l List) Append(obj Objecter) {
-	C.PyList_Append(l.obj, obj.Obj())
+	r := C.PyList_Append(l.obj, obj.Obj())
+	check(r == 0, "failed to append item to list")
 }

object.go

@@ -117,10 +117,9 @@ func (obj Object) AttrFunc(name string) Func {
 
 func (obj Object) SetAttr(name string, value any) {
 	cname := AllocCStr(name)
-	if C.PyObject_SetAttrString(obj.obj, cname, From(value).obj) != 0 {
-		C.PyErr_Print()
-		panic(fmt.Errorf("failed to set attribute %s", name))
-	}
+	r := C.PyObject_SetAttrString(obj.obj, cname, From(value).obj)
+	C.PyErr_Print()
+	check(r == 0, fmt.Sprintf("failed to set attribute %s", name))
 	C.free(unsafe.Pointer(cname))
 }
 

python.go

@@ -21,7 +21,8 @@ func Initialize() {
 }
 
 func Finalize() {
-	C.Py_FinalizeEx()
+	r := C.Py_FinalizeEx()
+	check(r == 0, "failed to finalize Python")
 	typeMetaMap = make(map[*C.PyObject]*typeMeta)
 	pyTypeMap = make(map[reflect.Type]*C.PyObject)
 }
@@ -112,3 +113,11 @@ func RunString(code string) error {
 	}
 	return nil
 }
+
+// ----------------------------------------------------------------------------
+
+func check(b bool, msg string) {
+	if !b {
+		panic(msg)
+	}
+}

tuple.go

@@ -4,6 +4,7 @@ package gp
 #include <Python.h>
 */
 import "C"
+import "fmt"
 
 type Tuple struct {
 	Object
@@ -35,7 +36,8 @@ func (t Tuple) Get(index int) Object {
 func (t Tuple) Set(index int, obj Objecter) {
 	objObj := obj.Obj()
 	C.Py_IncRef(objObj)
-	C.PyTuple_SetItem(t.obj, C.Py_ssize_t(index), objObj)
+	r := C.PyTuple_SetItem(t.obj, C.Py_ssize_t(index), objObj)
+	check(r == 0, fmt.Sprintf("failed to set item %d in tuple", index))
 }
 
 func (t Tuple) Len() int {

unicode.go

@@ -32,7 +32,7 @@ func (s Str) Len() int {
 
 func (s Str) ByteLen() int {
 	var l C.long
-	C.PyUnicode_AsUTF8AndSize(s.obj, &l)
+	_ = C.PyUnicode_AsUTF8AndSize(s.obj, &l)
 	return int(l)
 }