Py_CompileString decref (#1810)

* update changelog

* fix memory leak in PyModule::from_code

* add PR link to changelog

* Add Py_DECREF also when PyImport_ExecCodeModuleEx fails

* Remove duplicated calls, simplify logic

Co-authored-by: messense <messense@icloud.com>

Co-authored-by: messense <messense@icloud.com>

CHANGELOG.md

@@ -28,8 +28,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Loosened the lower bound on the `num-complex` optional dependency to support
   interop with `rust-numpy` and `ndarray` when building with the MSRV of 1.41
   [#1799](https://github.com/PyO3/pyo3/pull/1799)
-- Add missing `Py_DECREF` to `Python::run_code` which fixes a memory leak when
-  calling Python from Rust. [#1806](https://github.com/PyO3/pyo3/pull/1806)
+- Add missing `Py_DECREF` to `Python::run_code` and `PyModule::from_code` which fixes a memory leak when
+  calling Python from Rust. [#1806](https://github.com/PyO3/pyo3/pull/1806), [#1810](https://github.com/PyO3/pyo3/pull/1810)
 
 ## [0.14.2] - 2021-08-09
 

src/types/module.rs

@@ -126,6 +126,7 @@ impl PyModule {
             }
 
             let mptr = ffi::PyImport_ExecCodeModuleEx(module.as_ptr(), cptr, filename.as_ptr());
+            ffi::Py_DECREF(cptr);
             if mptr.is_null() {
                 return Err(PyErr::api_call_failed(py));
             }