From cca4c51ca463ea02fa504331ff21bc313c80c7f3 Mon Sep 17 00:00:00 2001 From: Tim Stumbaugh Date: Tue, 9 May 2023 08:04:20 -0600 Subject: [PATCH] Update errors in string "Explicit conversions" docs (#4658) `PyUnicode_DecodeLatin1` requires you to pass in the `error` parameter. The code as it is in the docs didn't compile. There is a reference leak in the example code. `PyUnicode_DecodeLatin1` returns a new reference. Calling `py::str(PyObject*)` calls `PyObject_Str`, which also returns a new reference. That reference is managed by the `py::str` constructor (which correctly steals the reference, using the `stolen_t` constructor), but the original reference returned by `PyUnicode_DecodeLatin1` is never decref'd: it never makes it into an `object`, and it's never manually decremented. This fixes both of those issues. The code compiles, and I viewed the sphinx docs locally. --- docs/advanced/cast/strings.rst | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/docs/advanced/cast/strings.rst b/docs/advanced/cast/strings.rst index e246c5219..271716b4b 100644 --- a/docs/advanced/cast/strings.rst +++ b/docs/advanced/cast/strings.rst @@ -101,8 +101,11 @@ conversion has the same overhead as implicit conversion. m.def("str_output", []() { std::string s = "Send your r\xe9sum\xe9 to Alice in HR"; // Latin-1 - py::str py_s = PyUnicode_DecodeLatin1(s.data(), s.length()); - return py_s; + py::handle py_s = PyUnicode_DecodeLatin1(s.data(), s.length(), nullptr); + if (!py_s) { + throw py::error_already_set(); + } + return py::reinterpret_steal(py_s); } ); @@ -113,7 +116,8 @@ conversion has the same overhead as implicit conversion. The `Python C API `_ provides -several built-in codecs. +several built-in codecs. Note that these all return *new* references, so +use :cpp:func:`reinterpret_steal` when converting them to a :cpp:class:`str`. One could also use a third party encoding library such as libiconv to transcode