matplotlib · clin1234 · Jul 25, 2026 · Jul 25, 2026 · Jul 25, 2026 · Jul 25, 2026
diff --git a/src/_backend_agg.h b/src/_backend_agg.h
@@ -762,7 +762,7 @@ class span_conv_alpha
     void prepare()
     {
     }
-    void generate(color_type *span, int x, int y, unsigned len) const
+    void generate(color_type *span, [[maybe_unused]] int x, [[maybe_unused]] int y, unsigned len) const
     {
         do {
             span->a = (agg::int8u)((double)span->a * m_alpha);
@@ -1054,7 +1054,7 @@ class QuadMeshGenerator
             return 5;
         }
 
-        inline bool should_simplify()
+        constexpr bool should_simplify()
         {
             return false;
         }

diff --git a/src/_c_internal_utils.cpp b/src/_c_internal_utils.cpp
@@ -99,7 +99,7 @@ static py::object
 mpl_GetCurrentProcessExplicitAppUserModelID(void)
 {
 #ifdef _WIN32
-    wchar_t* appid = NULL;
+    wchar_t* appid = nullptr;
     HRESULT hr = GetCurrentProcessExplicitAppUserModelID(&appid);
     if (FAILED(hr)) {
         PyErr_SetFromWindowsErr(hr);

diff --git a/src/_image_resample.h b/src/_image_resample.h
@@ -548,7 +548,7 @@ class span_conv_alpha
 
     void prepare() {}
 
-    void generate(color_type* span, int x, int y, unsigned len) const
+    void generate(color_type* span, [[maybe_unused]] int x, [[maybe_unused]]  int y, unsigned len) const
     {
         if (m_alpha != 1.0) {
             do {

diff --git a/src/_path.h b/src/_path.h
@@ -116,7 +116,7 @@ void point_in_path_impl(PointArray &points, PathIterator &path, ResultArray &ins
     bool all_done;
 
     size_t n = safe_first_shape(points);
-    assert(safe_first_shape(inside_flag) >= n);
+    assert(static_cast<size_t>(safe_first_shape(inside_flag)) >= n);
 
     std::vector<uint8_t> yflag0(n);
     std::vector<uint8_t> subpath_flag(n);
@@ -238,13 +238,13 @@ void point_in_path_impl(PointArray &points, PathIterator &path, ResultArray &ins
 }
 
 template <class PathIterator, class PointArray, class ResultArray>
-inline void points_in_path(PointArray &points,
+constexpr void points_in_path(PointArray &points,
                            const double r,
                            PathIterator &path,
                            agg::trans_affine &trans,
                            ResultArray &result)
 {
-    assert(safe_first_shape(result) >= safe_first_shape(points));
+    assert(static_cast<py::ssize_t>(safe_first_shape(result)) >= safe_first_shape(points));
     for (auto i = 0; i < safe_first_shape(points); ++i) {
         result[i] = false;
     }
@@ -1021,6 +1021,14 @@ void __add_number(double val, char format_code, int precision,
 {
     char *str = PyOS_double_to_string(
         val, format_code, precision, Py_DTSF_ADD_DOT_0, nullptr);
+    if (str == nullptr) {
+        const char* template_msg = "Cannot call PyOS_double_to_string within %s "
+        "with the following arguments: val=%f, format_code=%c, precision=%d";
+        int sz = std::snprintf(nullptr, 0, template_msg, __func__, val, format_code, precision);
+        std::vector<char> buf(sz + 1); // note +1 for null terminator
+        std::sprintf(buf.data(), template_msg, __func__, val, format_code, precision); // certain to fit
+        throw std::invalid_argument(buf.data());
+    }
     // Delete trailing zeros and decimal point
     char *c = str + strlen(str) - 1;  // Start at last character.
     // Rewind through all the zeros and, if present, the trailing decimal

diff --git a/src/_qhull_wrapper.cpp b/src/_qhull_wrapper.cpp
@@ -133,6 +133,11 @@ class QhullInfo {
         }
     }
 
+    QhullInfo(QhullInfo& other) = delete;
+    QhullInfo(const QhullInfo& other) = delete;
+    QhullInfo& operator=(QhullInfo& other) = delete;
+    QhullInfo& operator=(const QhullInfo& other) = delete;
+
 private:
     FILE* error_file;
     qhT* qh;

diff --git a/src/_tkagg.cpp b/src/_tkagg.cpp
@@ -46,9 +46,9 @@ using namespace pybind11::literals;
  * also.
  */
 #define WIN32_DLL
-static inline PyObject *PyErr_SetFromWindowsErr(int ierr) {
+static constexpr PyObject *PyErr_SetFromWindowsErr(int ierr) {
     PyErr_SetString(PyExc_OSError, "Call to EnumProcessModules failed");
-    return NULL;
+    return nullptr;
 }
 #endif
 

diff --git a/src/array.h b/src/array.h
@@ -22,17 +22,17 @@ class scalar
     {
     }
 
-    T &operator()(int i, int j = 0, int k = 0)
+    T &operator()([[maybe_unused]] int i, [[maybe_unused]] int j = 0, [[maybe_unused]] int k = 0)
     {
         return m_value;
     }
 
-    const T &operator()(int i, int j = 0, int k = 0) const
+    const T &operator()([[maybe_unused]] int i, [[maybe_unused]] int j = 0, [[maybe_unused]] int k = 0) const
     {
         return m_value;
     }
 
-    int shape(size_t i)
+    int shape([[maybe_unused]] size_t i)
     {
         return 1;
     }
@@ -58,22 +58,22 @@ class empty
 
     empty() = default;
 
-    T &operator()(int i, int j = 0, int k = 0)
+    T &operator()([[maybe_unused]] int i, [[maybe_unused]] int j = 0, [[maybe_unused]] int k = 0)
     {
         throw std::runtime_error("Accessed empty array");
     }
 
-    const T &operator()(int i, int j = 0, int k = 0) const
+    const T &operator()([[maybe_unused]] int i, [[maybe_unused]] int j = 0, [[maybe_unused]] int k = 0) const
     {
         throw std::runtime_error("Accessed empty array");
     }
 
-    sub_t operator[](int i) const
+    sub_t operator[]([[maybe_unused]] int i) const
     {
         return empty<T>();
     }
 
-    int shape(size_t i) const
+    int shape([[maybe_unused]] size_t i) const
     {
         return 0;
     }

diff --git a/src/ft2font.cpp b/src/ft2font.cpp
@@ -4,8 +4,10 @@
 #include "mplutils.h"
 
 #include <algorithm>
+#include <cassert>
 #include <cstdio>
 #include <iterator>
+#include <limits>
 #include <map>
 #include <set>
 #include <stdexcept>
@@ -17,8 +19,18 @@
 #endif
 
 FT2Image::FT2Image(unsigned long width, unsigned long height)
-    : m_buffer((unsigned char *)calloc(width * height, 1)), m_width(width), m_height(height)
+    : m_width(width), m_height(height)
 {
+    size_t buffer_size = width * height;
+    if (buffer_size != 0 && buffer_size / width != height) {
+        const char* template_msg = "Cannot allocate a FT2Image "
+        "with the following arguments: width=%lu, height=%lu";
+        int sz = std::snprintf(nullptr, 0, template_msg, width, height);
+        std::vector<char> buf(sz + 1); // note +1 for null terminator
+        std::sprintf(buf.data(), template_msg, width, height); // certain to fit
+        throw std::overflow_error(buf.data());
+    }
+    m_buffer = static_cast<unsigned char *>(calloc(width * height, 1));
 }
 
 FT2Image::~FT2Image()
@@ -148,7 +160,10 @@ static FT_Outline_Funcs ft_outline_funcs = {
     ft_outline_move_to,
     ft_outline_line_to,
     ft_outline_conic_to,
-    ft_outline_cubic_to};
+    ft_outline_cubic_to,
+    0,
+    0,
+};
 
 void
 FT2Font::get_path(std::vector<double> &vertices, std::vector<unsigned char> &codes)
@@ -169,8 +184,7 @@ FT2Font::get_path(std::vector<double> &vertices, std::vector<unsigned char> &cod
     codes.reserve(estimated_points);
     if (FT_Error error = FT_Outline_Decompose(
             &face->glyph->outline, &ft_outline_funcs, &decomposer)) {
-        throw std::runtime_error("FT_Outline_Decompose failed with error " +
-                                 std::to_string(error));
+        THROW_FT_ERROR("Decompose font outline", error);
     }
     if (vertices.empty()) {  // Don't append CLOSEPOLY to null glyphs.
         return;
@@ -474,12 +488,12 @@ void FT2Font::set_text(
         FT_Error error;
         error = FT_Load_Glyph(rglyph.ftface, rglyph.index, flags);
         if (error) {
-            throw std::runtime_error("failed to load glyph");
+            THROW_FT_ERROR("Loading glyphs", error);
         }
         FT_Glyph thisGlyph;
         error = FT_Get_Glyph(rglyph.ftface->glyph, &thisGlyph);
         if (error) {
-            throw std::runtime_error("failed to get glyph");
+            THROW_FT_ERROR("Getting glyphs", error);
         }
 
         pen.x += rglyph.x_offset;

diff --git a/src/ft2font.h b/src/ft2font.h
@@ -20,6 +20,7 @@
 extern "C" {
 #include <ft2build.h>
 #include FT_BITMAP_H
+#include FT_ERRORS_H
 #include FT_FREETYPE_H
 #include FT_GLYPH_H
 #include FT_OUTLINE_H
@@ -37,7 +38,7 @@ namespace py = pybind11;
 #define FIXED_MINOR(val) (unsigned short)(val & 0xffff)
 
 // Error handling (error codes are loaded as described in fterror.h).
-inline char const* ft_error_string(FT_Error error) {
+constexpr char const* ft_error_string(FT_Error error) {
 #undef __FTERRORS_H__
 #define FT_ERROR_START_LIST     switch (error) {
 #define FT_ERRORDEF( e, v, s )    case v: return s;

diff --git a/src/ft2font_wrapper.cpp b/src/ft2font_wrapper.cpp
@@ -1,3 +1,4 @@
+#include <memory>
 #define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION
 #include <pybind11/pybind11.h>
 #include <pybind11/native_enum.h>
@@ -298,11 +299,10 @@ class PyFT2Font final : public FT2Font
 
     void ft_glyph_warn(FT_ULong charcode, std::set<FT_String*> family_names)
     {
-        std::set<FT_String*>::iterator it = family_names.begin();
-        std::stringstream ss;
-        ss<< (*it ? *it : "unknown family name");
-        while(++it != family_names.end()){
-            ss<<", "<< (*it ? *it : "unknown family name");
+        std::ostringstream ss;
+        for (const auto& fname : family_names) {
+            ss << (fname != nullptr ? fname : "unknown family name");
+            if (fname != *family_names.rbegin()) ss << ", ";
         }
 
         auto text_helpers = py::module_::import("matplotlib._text_helpers");
@@ -366,16 +366,15 @@ read_from_file_callback(FT_Stream stream, unsigned long offset, unsigned char *b
 static void
 close_file_callback(FT_Stream stream)
 {
-    PyObject *type, *value, *traceback;
-    PyErr_Fetch(&type, &value, &traceback);
+    PyObject* exc = PyErr_GetRaisedException();
     PyFT2Font *self = (PyFT2Font *)stream->descriptor.pointer;
     try {
         self->py_file.attr("close")();
     } catch (py::error_already_set &eas) {
         eas.discard_as_unraisable(__func__);
     }
     self->py_file = py::object();
-    PyErr_Restore(type, value, traceback);
+    PyErr_SetRaisedException(exc);
 }
 
 const char *PyFT2Font_init__doc__ = R"""(
@@ -400,10 +399,9 @@ const char *PyFT2Font_init__doc__ = R"""(
             This API is private: do not use it directly.
 )""";
 
-static PyFT2Font *
-PyFT2Font_init(FT_Library ft2Library, py::object filename,
-               std::optional<long> hinting_factor = std::nullopt,
-               FT_Long face_index = 0,
+static std::unique_ptr<PyFT2Font>
+PyFT2Font_init(FT_Library ft2Library, py::object filename, std::optional<long> hinting_factor = std::nullopt,
+               FT_ULong face_index = 0,
                std::optional<std::vector<PyFT2Font *>> fallback_list = std::nullopt,
                std::optional<int> kerning_factor = std::nullopt,
                bool warn_if_used = false)
@@ -421,7 +419,7 @@ PyFT2Font_init(FT_Library ft2Library, py::object filename,
         kerning_factor = 0;
     }
 
-    if (face_index < 0 || face_index > 0xffff) {
+    if (face_index > 0xffff) {
         throw std::range_error("face_index must be between 0 and 65535, inclusive");
     }
 
@@ -432,7 +430,7 @@ PyFT2Font_init(FT_Library ft2Library, py::object filename,
                   std::back_inserter(fallback_fonts));
     }
 
-    auto self = new PyFT2Font(fallback_fonts, warn_if_used);
+    auto self = std::make_unique<PyFT2Font>(fallback_fonts, warn_if_used);
     self->set_kerning_factor(*kerning_factor);
 
     if (fallback_list) {
@@ -446,7 +444,7 @@ PyFT2Font_init(FT_Library ft2Library, py::object filename,
     self->stream.base = nullptr;
     self->stream.size = 0x7fffffff;  // Unknown size.
     self->stream.pos = 0;
-    self->stream.descriptor.pointer = self;
+    self->stream.descriptor.pointer = self.get();
     self->stream.read = &read_from_file_callback;
     FT_Open_Args open_args;
     memset((void *)&open_args, 0, sizeof(FT_Open_Args));
@@ -1572,10 +1570,10 @@ PYBIND11_MODULE(ft2font, m, py::mod_gil_not_used())
             [ft2Library](
                 py::object filename,
                 std::optional<long> hinting_factor = std::nullopt,
-                FT_Long face_index = 0,
+                FT_ULong face_index = 0,
                 std::optional<std::vector<PyFT2Font *>> fallback_list = std::nullopt,
                 std::optional<int> kerning_factor = std::nullopt,
-                bool warn_if_used = false) -> PyFT2Font *
+                bool warn_if_used = false) -> std::unique_ptr<PyFT2Font>
             {
                 return PyFT2Font_init(ft2Library, filename, hinting_factor, face_index,
                                       fallback_list, kerning_factor, warn_if_used);

diff --git a/src/mplutils.h b/src/mplutils.h
@@ -28,12 +28,12 @@
 #endif
 
 
-inline int mpl_round_to_int(double v)
+constexpr int mpl_round_to_int(double v)
 {
     return (int)(v + ((v >= 0.0) ? 0.5 : -0.5));
 }
 
-inline double mpl_round(double v)
+constexpr double mpl_round(double v)
 {
     return (double)mpl_round_to_int(v);
 }
@@ -60,7 +60,7 @@ namespace py = pybind11;
 using namespace pybind11::literals;
 
 template<typename T>
-inline void check_trailing_shape(T array, char const* name, long d1)
+constexpr void check_trailing_shape(T array, char const* name, long d1)
 {
     if (array.ndim() != 2) {
         throw py::value_error(
@@ -79,7 +79,7 @@ inline void check_trailing_shape(T array, char const* name, long d1)
 }
 
 template<typename T>
-inline void check_trailing_shape(T array, char const* name, long d1, long d2)
+constexpr void check_trailing_shape(T array, char const* name, long d1, long d2)
 {
     if (array.ndim() != 3) {
         throw py::value_error(