From 92416fb6e86614bef33c218bcb4ac146266964c5 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Fri, 21 Nov 2025 10:52:14 +0100
Subject: [PATCH] Use std::visit to exhaust std::variant possibilities

This makes it unnecessary to silence impossible "unhandled" cases.
---
 src/ft2font_wrapper.cpp | 46 +++++++++++++++++------------------------
 src/mplutils.h          | 15 ++++++++------
 2 files changed, 28 insertions(+), 33 deletions(-)

diff --git a/src/ft2font_wrapper.cpp b/src/ft2font_wrapper.cpp
index 08bb27f024f2..f8360449ef77 100644
--- a/src/ft2font_wrapper.cpp
+++ b/src/ft2font_wrapper.cpp
@@ -8,6 +8,7 @@
 #endif
 
 #include "ft2font.h"
+#include "mplutils.h"
 
 #include <set>
 #include <sstream>
@@ -617,20 +618,15 @@ PyFT2Font_set_text(PyFT2Font *self, std::u32string_view text, double angle = 0.0
                    std::variant<FT2Font::LanguageType, std::string> languages_or_str = nullptr)
 {
     std::vector<double> xys;
-
-    FT2Font::LanguageType languages;
-    if (auto value = std::get_if<FT2Font::LanguageType>(&languages_or_str)) {
-        languages = std::move(*value);
-    } else if (auto value = std::get_if<std::string>(&languages_or_str)) {
-        languages = std::vector<FT2Font::LanguageRange>{
-            FT2Font::LanguageRange{*value, 0, text.size()}
-        };
-    } else {
-        // NOTE: this can never happen as pybind11 would have checked the type in the
-        // Python wrapper before calling this function, but we need to keep the
-        // std::get_if instead of std::get for macOS 10.12 compatibility.
-        throw py::type_error("languages must be str or list of tuple");
-    }
+    FT2Font::LanguageType languages = std::visit(overloaded {
+        [](FT2Font::LanguageType languages) {
+            return languages;
+        },
+        [&](std::string value) {
+            return FT2Font::LanguageType{{
+                FT2Font::LanguageRange{value, 0, text.size()}}};
+        }
+    }, languages_or_str);
 
     self->set_text(text, angle, static_cast<FT_Int32>(flags), features, languages, xys);
 
@@ -1340,19 +1336,15 @@ PyFT2Font_layout(PyFT2Font *self, std::u32string text, LoadFlags flags,
 {
     const auto load_flags = static_cast<FT_Int32>(flags);
 
-    FT2Font::LanguageType languages;
-    if (auto value = std::get_if<FT2Font::LanguageType>(&languages_or_str)) {
-        languages = std::move(*value);
-    } else if (auto value = std::get_if<std::string>(&languages_or_str)) {
-        languages = std::vector<FT2Font::LanguageRange>{
-            FT2Font::LanguageRange{*value, 0, text.size()}
-        };
-    } else {
-        // NOTE: this can never happen as pybind11 would have checked the type in the
-        // Python wrapper before calling this function, but we need to keep the
-        // std::get_if instead of std::get for macOS 10.12 compatibility.
-        throw py::type_error("languages must be str or list of tuple");
-    }
+    FT2Font::LanguageType languages = std::visit(overloaded {
+        [](FT2Font::LanguageType languages) {
+            return languages;
+        },
+        [&](std::string value) {
+            return FT2Font::LanguageType{{
+                FT2Font::LanguageRange{value, 0, text.size()}}};
+        }
+    }, languages_or_str);
 
     std::set<FT_String*> glyph_seen_fonts;
     auto glyphs = self->layout(text, load_flags, features, languages, glyph_seen_fonts);
diff --git a/src/mplutils.h b/src/mplutils.h
index 475530b3d880..2a7d63c871f5 100644
--- a/src/mplutils.h
+++ b/src/mplutils.h
@@ -49,8 +49,6 @@ enum {
 };
 
 #ifdef __cplusplus  // not for macosx.m
-// Check that array has shape (N, d1) or (N, d1, d2).  We cast d1, d2 to longs
-// so that we don't need to access the NPY_INTP_FMT macro here.
 #include <pybind11/pybind11.h>
 #include <pybind11/numpy.h>
 #include <array>
@@ -59,6 +57,12 @@ enum {
 namespace py = pybind11;
 using namespace pybind11::literals;
 
+// Helper for std::visit.
+template<typename... Ts> struct overloaded : Ts... { using Ts::operator()...; };
+template<typename... Ts> overloaded(Ts...) -> overloaded<Ts...>;
+
+// Check that array has shape (N, d1) or (N, d1, d2).  We cast d1, d2 to longs
+// so that we don't need to access the NPY_INTP_FMT macro here.
 template<typename T>
 inline void check_trailing_shape(T array, char const* name, long d1)
 {
@@ -97,11 +101,10 @@ inline void check_trailing_shape(T array, char const* name, long d1, long d2)
     }
 }
 
-/* In most cases, code should use safe_first_shape(obj) instead of obj.shape(0), since
-   safe_first_shape(obj) == 0 when any dimension is 0. */
+// In most cases, code should use safe_first_shape(obj) instead of
+// obj.shape(0), since safe_first_shape(obj) == 0 when any dimension is 0.
 template <typename T, py::ssize_t ND>
-py::ssize_t
-safe_first_shape(const py::detail::unchecked_reference<T, ND> &a)
+py::ssize_t safe_first_shape(const py::detail::unchecked_reference<T, ND> &a)
 {
     bool empty = (ND == 0);
     for (py::ssize_t i = 0; i < ND; i++) {