Possible memory leak in `_tkinter.c` on Windows

[ByteFlowing1337]

Bug report

Bug description:

The code below should call Py_DECREF(v); before returning NULL:

cpython/Modules/_tkinter.c

Lines 708 to 716 in 0066fd7

	str_path = _get_tcl_lib_path();
	if (str_path == NULL && PyErr_Occurred()) {
	return NULL;
	}
	if (str_path != NULL) {
	utf8_path = PyUnicode_AsUTF8String(str_path);
	if (utf8_path == NULL) {
	return NULL;
	}

The code below shouldn't overwrite the pointer tcl_library_path directly:

cpython/Modules/_tkinter.c

Lines 131 to 136 in 0066fd7

	tcl_library_path = PyUnicode_FromString("\\tcl\\tcl" TCL_VERSION);
	if (tcl_library_path == NULL) {
	Py_DECREF(prefix);
	return NULL;
	}
	tcl_library_path = PyUnicode_Concat(prefix, tcl_library_path);

I will submit a PR.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Windows

Linked PRs

• gh-151337: Avoid possible memory leak in _tkinter.c on Windows. #151340