From dc91a40f5d8b48d30c05b5847887598198891328 Mon Sep 17 00:00:00 2001
From: DualFroz <me@dualfroz.com>
Date: Fri, 11 Sep 2026 18:39:49 +0200
Subject: [PATCH] test: cover testHeaderCoexistence

---
 tests/testHeaderCoexistence.cpp | 154 ++++++++++++++++++++++++++++++++
 1 file changed, 154 insertions(+)
 create mode 100644 tests/testHeaderCoexistence.cpp

diff --git a/tests/testHeaderCoexistence.cpp b/tests/testHeaderCoexistence.cpp
new file mode 100644
index 0000000..ac98c00
--- /dev/null
+++ b/tests/testHeaderCoexistence.cpp
@@ -0,0 +1,154 @@
+// Every public header pulled into ONE translation unit.
+//
+// This exists because it already failed for real: two modules independently
+// declared vf::DamageSource (an enum in Survival.h, a struct in Damage.h) and
+// nothing caught it, because no single translation unit ever included both.
+// The combined binary linked and then died with SIGSEGV instead of a compiler
+// error. A duplicate type, a duplicate free function or a conflicting
+// declaration between any two modules now fails this file at compile time.
+//
+// Do not split this file and do not include headers selectively - the whole
+// point is that all of them meet here.
+
+#include "vf/Advancement.h"
+#include "vf/Anvil.h"
+#include "vf/Behavior.h"
+#include "vf/BiomeGen.h"
+#include "vf/Block.h"
+#include "vf/BlockTick.h"
+#include "vf/Boss.h"
+#include "vf/Brewing.h"
+#include "vf/Brush.h"
+#include "vf/Chunk.h"
+#include "vf/ChunkCache.h"
+#include "vf/ChunkPipeline.h"
+#include "vf/ChunkSync.h"
+#include "vf/Circuit.h"
+#include "vf/Climate.h"
+#include "vf/Codec.h"
+#include "vf/Command.h"
+#include "vf/Container.h"
+#include "vf/ContainerMenu.h"
+#include "vf/Crafting.h"
+#include "vf/Damage.h"
+#include "vf/DataPack.h"
+#include "vf/Dimension.h"
+#include "vf/Dispenser.h"
+#include "vf/EditHistory.h"
+#include "vf/Effect.h"
+#include "vf/Enchant.h"
+#include "vf/EndGen.h"
+#include "vf/Entity.h"
+#include "vf/Equipment.h"
+#include "vf/Explosion.h"
+#include "vf/Farming.h"
+#include "vf/Fluid.h"
+#include "vf/Frustum.h"
+#include "vf/Gossip.h"
+#include "vf/Hopper.h"
+#include "vf/Inventory.h"
+#include "vf/Item.h"
+#include "vf/ItemStack.h"
+#include "vf/JobSystem.h"
+#include "vf/Json.h"
+#include "vf/LightEngine.h"
+#include "vf/Lighting.h"
+#include "vf/LitMesh.h"
+#include "vf/Loot.h"
+#include "vf/LootTables.h"
+#include "vf/Math.h"
+#include "vf/Mesh.h"
+#include "vf/Minecart.h"
+#include "vf/Mob.h"
+#include "vf/Nbt.h"
+#include "vf/NetServer.h"
+#include "vf/NetSession.h"
+#include "vf/NetherGen.h"
+#include "vf/Noise.h"
+#include "vf/NoiseAdv.h"
+#include "vf/Pathfind.h"
+#include "vf/Physics.h"
+#include "vf/Piston.h"
+#include "vf/PlayerData.h"
+#include "vf/Portal.h"
+#include "vf/PotionCatalog.h"
+#include "vf/Protocol.h"
+#include "vf/Raid.h"
+#include "vf/Rail.h"
+#include "vf/RandomTick.h"
+#include "vf/Raycast.h"
+#include "vf/Region.h"
+#include "vf/RegionCompact.h"
+#include "vf/SaveIntegrity.h"
+#include "vf/SaveMigration.h"
+#include "vf/SaveV3.h"
+#include "vf/Schematic.h"
+#include "vf/Scoreboard.h"
+#include "vf/Selection.h"
+#include "vf/Serialize.h"
+#include "vf/SlotAction.h"
+#include "vf/Spawning.h"
+#include "vf/Streaming.h"
+#include "vf/StructureGen.h"
+#include "vf/Structures.h"
+#include "vf/Survival.h"
+#include "vf/Terrain.h"
+#include "vf/TilePalette.h"
+#include "vf/TileTexture.h"
+#include "vf/TimeOfDay.h"
+#include "vf/Trade.h"
+#include "vf/Transport.h"
+#include "vf/Villager.h"
+#include "vf/Weather.h"
+#include "vf/World.h"
+#include "vf/WorldBackup.h"
+#include "vf/WorldGen.h"
+#include "vf/WorldSim.h"
+
+#include "testHarness.h"
+
+#include <cstdio>
+#include <filesystem>
+#include <fstream>
+#include <set>
+#include <string>
+
+using namespace vf;
+
+namespace {
+
+// Walk up from the working directory until the source tree is found, so the
+// binary can be launched from the repository root (what `make test` does) or
+// from one level below it.
+std::filesystem::path findRepoRoot() {
+    std::filesystem::path here = std::filesystem::current_path();
+    for (int step = 0; step < 4; ++step) {
+        if (std::filesystem::is_directory(here / "core" / "include" / "vf") &&
+            std::filesystem::is_regular_file(here / "tests" / "testHeaderCoexistence.cpp")) {
+            return here;
+        }
+        if (!here.has_parent_path() || here.parent_path() == here) break;
+        here = here.parent_path();
+    }
+    return {};
+}
+
+} // namespace
+
+// The guard above is only worth as much as its include list. A module added
+// without a line here would quietly stop being checked, which is exactly how
+// the first collision slipped through. This test reads the directory and this
+// file's own source and fails when the two disagree.
+VF_TEST(everyPublicHeaderIsListedInTheCoexistenceGuard) {
+    std::filesystem::path root = findRepoRoot();
+    CHECK(!root.empty());
+    if (root.empty()) return;
+
+    std::set<std::string> onDisk;
+    for (const auto& entry : std::filesystem::directory_iterator(root / "core" / "include" / "vf")) {
+        if (entry.is_regular_file() && entry.path().extension() == ".h") {
+            onDisk.insert(entry.path().filename().string());
+        }
+    }
+    CHECK(onDisk.size() > 60u);
+