Memory leak fixes in the wrapper (#199)

* memory leak fixes
* Tweaks for workflow for CI changes since last merge.

Author: vineetbansal

.github/workflows/build_default.yml

@@ -46,8 +46,8 @@ jobs:
             cibw_archs: "auto"
           - os: windows-2022
             cibw_archs: "auto64"
-          # Include macos-13 to get Intel x86_64 macs and maos-latest to get the Aaarch64 macs
-          - os: macos-13
+          # Include macos-15-intel to get Intel x86_64 macs and macos-latest to get the Aaarch64 macs
+          - os: macos-15-intel
             cibw_archs: "x86_64"
           - os: macos-latest
             cibw_archs: "arm64"

.github/workflows/build_mkl.yml

@@ -17,9 +17,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # macos-latest now uses arm64 runners, but MKL is x86_64 only, so restrict to the macos-13 runners
+        # macos-latest now uses arm64 runners, but MKL is x86_64 only, so restrict to the macos-15-intel runners
         # to get x86_64 architecture.
-        os: [ubuntu-latest, macos-13]
+        os: [ubuntu-latest, macos-15-intel]
 
     steps:
     - uses: actions/checkout@master

CMakeLists.txt

@@ -1,6 +1,9 @@
 cmake_minimum_required(VERSION 3.15...3.26)
 project(ext)
 
+set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
 set(PYTHON "ON")
 set(OSQP_BUILD_UNITTESTS "OFF")
 set(OSQP_USE_LONG "OFF")

cibuildwheel.toml

@@ -6,15 +6,17 @@ before-build = "rm -rf {package}/osqp_sources/build"
 # Install CPU-only version of torch beforehand since that allows cibuildwheel
 # to satisfy the "test" dependency group install, but much faster. The runtime
 # cost of torch-based osqp tests are considered negligible so torch-cpu is ok.
-before-test = "pip install torch --index-url https://download.pytorch.org/whl/cpu"
+before-test = 'pip install scipy --prefer-binary && pip install torch --index-url https://download.pytorch.org/whl/cpu'
 test-groups = ["test"]
 test-command = "python -m pytest -s {project}/src/osqp/tests"
-# 09/10/25 - Skip testing on cp313-manylinux_aarch64 because torch/numpy deps are unsatisfiable
-test-skip = "cp313-manylinux_aarch64"
 
-[tool.cibuildwheel.macos]
-# 02/13/25 - Skip testing on cp313-macosx_x86_64 because torch/numpy deps are unsatisfiable
-test-skip = "cp313-macosx_x86_64"
+[[tool.cibuildwheel.overrides]]
+# Platforms on which installing pytorch is problematic, so we skip testing
+# the `osqp.nn` module
+select = "*manylinux_aarch64 cp313-macosx_x86_64"
+before-test = 'pip install scipy --prefer-binary'
+test-groups = ["test-no-nn"]
+test-command = "python -m pytest -s {project}/src/osqp/tests --continue-on-collection-errors --ignore={project}/src/osqp/tests/nn_test.py"
 
 [tool.cibuildwheel.pyodide]
 build = "cp312-pyodide_wasm32"

src/bindings.cpp.in

@@ -1,4 +1,5 @@
 #include <iostream>
+#include <memory>
 #include <pybind11/pybind11.h>
 #include <pybind11/numpy.h>
 
@@ -132,6 +133,7 @@ class PyOSQPSolver {
         const CSC& _A;
         py::array_t<OSQPFloat> _u;
         OSQPSolver *_solver;
+        std::unique_ptr<PyOSQPSolution> _solution_cache;
 };
 
 PyOSQPSolver::PyOSQPSolver(
@@ -143,8 +145,7 @@ PyOSQPSolver::PyOSQPSolver(
         OSQPInt m,
         OSQPInt n,
         const OSQPSettings *settings
-): m(m), n(n), _P(P), _A(A) {
-    this->_solver = new OSQPSolver();
+): m(m), n(n), _P(P), _A(A), _solver(nullptr) {
     this->_q = q;
     this->_l = l;
     this->_u = u;
@@ -164,8 +165,10 @@ OSQPSettings* PyOSQPSolver::get_settings() {
 }
 
 PyOSQPSolution& PyOSQPSolver::get_solution() {
-    PyOSQPSolution* solution = new PyOSQPSolution(*this->_solver->solution, this->m, this->n);
-    return *solution;
+    if (!_solution_cache) {
+        _solution_cache = std::make_unique<PyOSQPSolution>(*this->_solver->solution, this->m, this->n);
+    }
+    return *_solution_cache;
 }
 
 OSQPInfo* PyOSQPSolver::get_info() {