From 566fc9f76a0ea323a93af275cdc29d8183c1e510 Mon Sep 17 00:00:00 2001
From: "Joseph C. Sible" <josephcsible@users.noreply.github.com>
Date: Thu, 25 Dec 2025 17:42:00 -0500
Subject: [PATCH 1/4] Fix two potential use-after-frees in monster's refcount
 code

---
 shmup.cpp | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/shmup.cpp b/shmup.cpp
index 1a4f1fff..ee0f8169 100644
--- a/shmup.cpp
+++ b/shmup.cpp
@@ -83,15 +83,10 @@ struct monster {
 
   void rebasePat(const shiftmatrix& new_pat, cell *tgt);
   
-  void remove_reference() {
-    refs--;
-    if(!refs) {
-      if(parent) parent->remove_reference();
-      delete this;
-      }
-    }
+  void remove_reference();
   
   void set_parent(monster *par) {
+    if(parent == par) return;
     if(parent) parent->remove_reference();
     parent = par;
     parent->refs++;
@@ -128,6 +123,15 @@ typedef multimap<cell*, monster*>::iterator mit;
 
 EX vector<monster*> active, nonvirtual, additional;
 
+void monster::remove_reference() {
+  refs--;
+  if(!refs) {
+    if(parent) parent->remove_reference();
+    nonvirtual.erase(std::remove(nonvirtual.begin(), nonvirtual.end(), this), nonvirtual.end());
+    delete this;
+    }
+  }
+
 cell *findbaseAround(shiftpoint p, cell *around, int maxsteps) {
 
   if(quotient || fake::split()) {

From d6efc2b99b29712d06cd47c57fc94c525bccc31a Mon Sep 17 00:00:00 2001
From: "Joseph C. Sible" <josephcsible@users.noreply.github.com>
Date: Mon, 16 Feb 2026 20:42:21 -0500
Subject: [PATCH 2/4] Fix #494: Add libpng-dev to list of packages to install

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 142c5ca9..f475d924 100644
--- a/README.md
+++ b/README.md
@@ -51,7 +51,7 @@ not the data, which is available on [itch.io](https://zenorogue.itch.io/rogueviz
 
 On Linux with apt-get:
 
-```sudo apt-get install make g++ libsdl1.2-dev libsdl-ttf2.0-dev libsdl-gfx1.2-dev libsdl-mixer1.2-dev libglew-dev```
+```sudo apt-get install make g++ libsdl1.2-dev libsdl-ttf2.0-dev libsdl-gfx1.2-dev libsdl-mixer1.2-dev libglew-dev libpng-dev```
 
 On macOS with Homebrew:
 

From 330ba7588961d236c1841bccf1e8f5fb8052d1b5 Mon Sep 17 00:00:00 2001
From: "Joseph C. Sible" <josephcsible@users.noreply.github.com>
Date: Tue, 17 Feb 2026 21:05:58 -0500
Subject: [PATCH 3/4] Fix #496: Log why get_display_modes needs to use fallback
 values

---
 config.cpp | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/config.cpp b/config.cpp
index 101a1880..c2f2b41c 100644
--- a/config.cpp
+++ b/config.cpp
@@ -1075,8 +1075,18 @@ EX vector<int> get_display_modes(char which) {
 
   #if SDLVER >= 2
   SDL_DisplayMode mode;
-  for(int m=0; m<SDL_GetNumVideoDisplays(); m++) {
-    for(int i=0; i<SDL_GetNumDisplayModes(m); i++) {
+  int num_video_displays = SDL_GetNumVideoDisplays();
+  if(num_video_displays < 0)
+    println(hlog, "SDL_GetNumVideoDisplays error: ", SDL_GetError());
+  else if(num_video_displays == 0)
+    println(hlog, "SDL_GetNumVideoDisplays returned 0");
+  for(int m=0; m<num_video_displays; m++) {
+    int num_display_modes = SDL_GetNumDisplayModes(m);
+    if(num_display_modes < 0)
+      println(hlog, "SDL_GetNumDisplayModes(", m, ") error: ", SDL_GetError());
+    else if(num_display_modes == 0)
+      println(hlog, "SDL_GetNumDisplayModes(", m, ") returned 0");
+    for(int i=0; i<num_display_modes; i++) {
       SDL_GetDisplayMode(m, i, &mode);
       if(which == 'x') seen.insert(mode.w);
       if(which == 'y') seen.insert(mode.h);
@@ -1085,7 +1095,13 @@ EX vector<int> get_display_modes(char which) {
 
   #else
   SDL_Rect **modes = SDL_ListModes(nullptr, 0);
-  if(modes && modes != (SDL_Rect**)-1) for(int i=0; modes[i]; i++) {
+  if(!modes)
+    println(hlog, "SDL_ListModes: No modes available!");
+  else if(modes == (SDL_Rect**)-1)
+    println(hlog, "SDL_ListModes: All resolutions available.");
+  else if(!*modes)
+    println(hlog, "SDL_ListModes returned an empty array");
+  else for(int i=0; modes[i]; i++) {
     if(which == 'x') seen.insert(modes[i]->w);
     if(which == 'y') seen.insert(modes[i]->h);
     }

From 5fa35e5214e6ea3079737e065dad982eecdecf70 Mon Sep 17 00:00:00 2001
From: "Joseph C. Sible" <josephcsible@users.noreply.github.com>
Date: Tue, 17 Feb 2026 21:13:27 -0500
Subject: [PATCH 4/4] Add missing override keywords to hopefully fix CI

---
 rogueviz/embeddings/compare.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/rogueviz/embeddings/compare.cpp b/rogueviz/embeddings/compare.cpp
index 81c3e664..b4bc4c9a 100644
--- a/rogueviz/embeddings/compare.cpp
+++ b/rogueviz/embeddings/compare.cpp
@@ -164,7 +164,7 @@ struct dmercator_embedding : abstract_embedding {
   virtual string name() override { return "dmercator"; }
   eGeometryClass get_geometry() override { return gcHyperbolic; }
   int get_dimension() override { return 3; }
-  hyperpoint as_hyperpoint(int id) {
+  hyperpoint as_hyperpoint(int id) override {
     auto& mc = mcs[id];
     hyperpoint h;
     for(int i=0; i<3; i++) 
@@ -175,7 +175,7 @@ struct dmercator_embedding : abstract_embedding {
 
   ld zero_distance(int id) override { return mcs[id].distance; }
 
-  ld distance(int a, int b) {
+  ld distance(int a, int b) override {
     if(a == b) return ld(0);
     ld da = mcs[a].distance;
     ld db = mcs[b].distance;