From 8503fe3c4fd025e3b6f835a4559a3edfaf55ba08 Mon Sep 17 00:00:00 2001
From: Ryan Lucia <ryan@luciaonline.net>
Date: Thu, 8 Oct 2026 13:45:24 -0700
Subject: [PATCH] Store the provider lists in vectors to work around a GCC bug

GCC miscompiles a namespace-scope std::initializer_list whose elements
are a mix of constant-initializable and non-constant ones: the static
initializer leaves the constant ones zeroed
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126472). Since #655 added
the extensions vector, the Dummy entries of the audio and video provider
lists are such elements in C++20, where std::vector's default
constructor is constexpr. With an affected GCC (at least 13 through
16.2; fixed for 16.3), every attempt to open audio or video therefore
dereferences a null provider name and crashes.

A std::vector is initialized correctly.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 src/audio_provider_factory.cpp | 8 ++++++--
 src/video_provider_manager.cpp | 8 ++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/audio_provider_factory.cpp b/src/audio_provider_factory.cpp
index 58c375bb03..bc682474a9 100644
--- a/src/audio_provider_factory.cpp
+++ b/src/audio_provider_factory.cpp
@@ -27,7 +27,7 @@
 #include <libaegisub/string.h>
 
 #include <algorithm>
-#include <initializer_list>
+#include <vector>
 
 using namespace agi;
 
@@ -42,7 +42,11 @@ struct factory {
 	std::vector<const char *> extensions;
 };
 
-const std::initializer_list<factory> providers = {
+// This can't be a std::initializer_list: GCC (at least 13 to 16.2) zeroes the
+// elements of one that can be constant-initialized (here, the ones with an
+// empty extensions list) when others can't be, leaving a null name.
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126472
+const std::vector<factory> providers = {
 	{"Dummy", CreateDummyAudioProvider, true, {}},
 	{"PCM", CreatePCMAudioProvider, true, {".w64", ".wav"}},
 #ifdef WITH_FFMS2
diff --git a/src/video_provider_manager.cpp b/src/video_provider_manager.cpp
index 97983f50a0..344dcc8a61 100644
--- a/src/video_provider_manager.cpp
+++ b/src/video_provider_manager.cpp
@@ -28,7 +28,7 @@
 #include <wx/translation.h>
 
 #include <algorithm>
-#include <initializer_list>
+#include <vector>
 
 std::unique_ptr<VideoProvider> CreateDummyVideoProvider(agi::fs::path const&, agi::ycbcr::Header, agi::BackgroundRunner *);
 std::unique_ptr<VideoProvider> CreateYUV4MPEGVideoProvider(agi::fs::path const&, agi::ycbcr::Header, agi::BackgroundRunner *);
@@ -45,7 +45,11 @@ namespace {
 		std::vector<const char *> extensions;
 	};
 
-	const std::initializer_list<factory> providers = {
+	// This can't be a std::initializer_list: GCC (at least 13 to 16.2) zeroes the
+	// elements of one that can be constant-initialized (here, the ones with an
+	// empty extensions list) when others can't be, leaving a null name.
+	// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126472
+	const std::vector<factory> providers = {
 		{"Dummy", CreateDummyVideoProvider, true, {}},
 		{"YUV4MPEG", CreateYUV4MPEGVideoProvider, true, {".y4m", ".yuv"}},
 #ifdef WITH_FFMS2