gh-115754: Use Py_GetConstant(Py_CONSTANT_EMPTY_STR) (#125194)

Replace PyUnicode_New(0, 0), PyUnicode_FromString("") and PyUnicode_FromStringAndSize("", 0) with Py_GetConstant(Py_CONSTANT_EMPTY_STR).

Author: vstinner

Doc/includes/newtypes/custom2.c

@@ -23,12 +23,12 @@ Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
  CustomObject *self;
  self = (CustomObject *) type->tp_alloc(type, 0);
  if (self != NULL) {
- self->first = PyUnicode_FromString("");
+ self->first = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (self->first == NULL) {
  Py_DECREF(self);
  return NULL;
  }
- self->last = PyUnicode_FromString("");
+ self->last = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (self->last == NULL) {
  Py_DECREF(self);
  return NULL;

Doc/includes/newtypes/custom3.c

@@ -23,12 +23,12 @@ Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
  CustomObject *self;
  self = (CustomObject *) type->tp_alloc(type, 0);
  if (self != NULL) {
- self->first = PyUnicode_FromString("");
+ self->first = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (self->first == NULL) {
  Py_DECREF(self);
  return NULL;
  }
- self->last = PyUnicode_FromString("");
+ self->last = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (self->last == NULL) {
  Py_DECREF(self);
  return NULL;

Doc/includes/newtypes/custom4.c

@@ -39,12 +39,12 @@ Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
  CustomObject *self;
  self = (CustomObject *) type->tp_alloc(type, 0);
  if (self != NULL) {
- self->first = PyUnicode_FromString("");
+ self->first = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (self->first == NULL) {
  Py_DECREF(self);
  return NULL;
  }
- self->last = PyUnicode_FromString("");
+ self->last = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (self->last == NULL) {
  Py_DECREF(self);
  return NULL;

Modules/_ctypes/_ctypes.c

@@ -4756,7 +4756,7 @@ Array_subscript(PyObject *myself, PyObject *item)
  wchar_t *dest;
 
  if (slicelen <= 0)
- return PyUnicode_New(0, 0);
+ return Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (step == 1) {
  return PyUnicode_FromWideChar(ptr + start,
  slicelen);
@@ -5438,7 +5438,7 @@ Pointer_subscript(PyObject *myself, PyObject *item)
  wchar_t *dest;
 
  if (len <= 0)
- return PyUnicode_New(0, 0);
+ return Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (step == 1) {
  return PyUnicode_FromWideChar(ptr + start,
  len);

Modules/_datetimemodule.c

@@ -2921,7 +2921,7 @@ delta_bool(PyDateTime_Delta *self)
 static PyObject *
 delta_repr(PyDateTime_Delta *self)
 {
- PyObject *args = PyUnicode_FromString("");
+ PyObject *args = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
 
  if (args == NULL) {
  return NULL;

Modules/_elementtree.c

@@ -196,7 +196,7 @@ list_join(PyObject* list)
  PyObject* joiner;
  PyObject* result;
 
- joiner = PyUnicode_FromStringAndSize("", 0);
+ joiner = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (!joiner)
  return NULL;
  result = PyUnicode_Join(joiner, list);
@@ -1317,7 +1317,7 @@ _elementtree_Element_findtext_impl(ElementObject *self, PyTypeObject *cls,
  PyObject* text = element_get_text((ElementObject*)item);
  if (text == Py_None) {
  Py_DECREF(item);
- return PyUnicode_New(0, 0);
+ return Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  }
  Py_XINCREF(text);
  Py_DECREF(item);

Modules/_functoolsmodule.c

@@ -604,7 +604,7 @@ partial_repr(partialobject *pto)
  return PyUnicode_FromString("...");
  }
 
- arglist = PyUnicode_FromString("");
+ arglist = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (arglist == NULL)
  goto done;
  /* Pack positional arguments */

Modules/_io/stringio.c

@@ -353,7 +353,7 @@ _stringio_readline(stringio *self, Py_ssize_t limit)
 
  /* In case of overseek, return the empty string */
  if (self->pos >= self->string_size)
- return PyUnicode_New(0, 0);
+ return Py_GetConstant(Py_CONSTANT_EMPTY_STR);
 
  start = self->buf + self->pos;
  if (limit < 0 || limit > self->string_size - self->pos)

Modules/_testcapi/datetime.c

@@ -129,7 +129,7 @@ static PyObject *
 get_timezones_offset_zero(PyObject *self, PyObject *args)
 {
  PyObject *offset = PyDelta_FromDSU(0, 0, 0);
- PyObject *name = PyUnicode_FromString("");
+ PyObject *name = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
  if (offset == NULL || name == NULL) {
  Py_XDECREF(offset);
  Py_XDECREF(name);

Modules/cjkcodecs/multibytecodec.c

@@ -669,7 +669,7 @@ _multibytecodec_MultibyteCodec_decode_impl(MultibyteCodecObject *self,
 
  if (datalen == 0) {
  ERROR_DECREF(errorcb);
- return make_tuple(PyUnicode_New(0, 0), 0);
+ return make_tuple(Py_GetConstant(Py_CONSTANT_EMPTY_STR), 0);
  }
 
  _PyUnicodeWriter_Init(&buf.writer);
@@ -1434,7 +1434,7 @@ mbstreamreader_iread(MultibyteStreamReaderObject *self,
  Py_ssize_t rsize;
 
  if (sizehint == 0)
- return PyUnicode_New(0, 0);
+ return Py_GetConstant(Py_CONSTANT_EMPTY_STR);
 
  _PyUnicodeWriter_Init(&buf.writer);
  buf.excobj = NULL;