fix: dynamically link rocksdb on dynamic nix builds

Fixes liburing error.

.forgejo/workflows/update-flake-hashes.yml

@@ -45,6 +45,9 @@ jobs:
 
           rm new_toolchain_hash.txt
 
+      - name: Update rocksdb
+        run: nix run .#update-rocksdb
+
       - name: Show diff
         run: git diff flake.nix nix
 

nix/default.nix

@@ -4,5 +4,6 @@
     ./packages
     ./devshell.nix
     ./fmt.nix
+    ./rocksdb-updater.nix
   ];
 }

nix/packages/continuwuity.nix

@@ -2,9 +2,10 @@
   lib,
   self,
   stdenv,
-  liburing,
+  rocksdb,
   craneLib,
   pkg-config,
+  liburing,
   rustPlatform,
   cargoExtraArgs ? "",
   rustflags ? "",
@@ -36,12 +37,17 @@ let
       pkg-config
       rustPlatform.bindgenHook
     ];
+
     buildInputs = lib.optionals stdenv.hostPlatform.isLinux [ liburing ];
-    doCheck = false;
+
     env = {
       CARGO_PROFILE = profile;
       RUSTFLAGS = rustflags;
     }
+    // (lib.optionalAttrs (rocksdb != null) {
+      ROCKSDB_INCLUDE_DIR = "${rocksdb}/include";
+      ROCKSDB_LIB_DIR = "${rocksdb}/lib";
+    })
     // (lib.optionalAttrs (target_cpu != null) {
       TARGET_CPU = target_cpu;
     });
@@ -52,6 +58,18 @@ craneLib.buildPackage (
     inherit cargoExtraArgs;
     cargoArtifacts = craneLib.buildDepsOnly attrs;
 
+    # Needed to make continuwuity link to rocksdb
+    postFixup = lib.optionalString (stdenv.hostPlatform.isLinux && rocksdb != null) ''
+      old_rpath="$(patchelf --print-rpath $out/bin/conduwuit)"
+      extra_rpath="${
+        lib.makeLibraryPath [
+          rocksdb
+        ]
+      }"
+
+      patchelf --set-rpath "$old_rpath:$extra_rpath" $out/bin/conduwuit
+    '';
+
     meta = {
       description = "A community-driven Matrix homeserver in Rust";
       mainProgram = "conduwuit";

nix/packages/default.nix

@@ -36,7 +36,10 @@
 
               default = pkgs.callPackage ./continuwuity.nix {
                 inherit self craneLib;
+
                 liburing = (if isStatic then pkgs.pkgsStatic else pkgs).liburing;
+                rocksdb = if isStatic then null else pkgs.callPackage ./rocksdb.nix { };
+
                 # extra features via `cargoExtraArgs`
                 cargoExtraArgs = "-F http3";
                 # extra RUSTFLAGS via `rustflags`

nix/packages/rocksdb.nix

@@ -0,0 +1,36 @@
+{
+  # stdenv,
+  # enableJemalloc ? stdenv.hostPlatform.isLinux,
+  enableJemalloc ? false,
+  rocksdb,
+  fetchFromGitea,
+  rust-jemalloc-sys-unprefixed,
+  ...
+}:
+(rocksdb.override {
+  # rocksdb fails to build with prefixed jemalloc, which is required on
+  # darwin due to [1]. In this case, fall back to building rocksdb with
+  # libc malloc. This should not cause conflicts, because all of the
+  # jemalloc symbols are prefixed.
+  #
+  # [1]: https://github.com/tikv/jemallocator/blob/ab0676d77e81268cd09b059260c75b38dbef2d51/jemalloc-sys/src/env.rs#L17
+  jemalloc = rust-jemalloc-sys-unprefixed;
+  inherit enableJemalloc;
+}).overrideAttrs
+  ({
+    version = "continuwuity-v0.5.0-unstable-2026-05-19";
+    src = fetchFromGitea {
+      domain = "forgejo.ellis.link";
+      owner = "continuwuation";
+      repo = "rocksdb";
+      rev = "3756b2b905e13216d8b56bcc783d814e7b073aff";
+      hash = "sha256-rSv4fr2bf9JJwdodgeuPCuceeh7k97KVxrAOC0wyPQY=";
+    };
+
+    # We have this already at https://forgejo.ellis.link/continuwuation/rocksdb/commit/a935c0273e1ba44eacf88ce3685a9b9831486155
+    # Unsetting `patches` so we don't have to revert it and make this nix exclusive
+    patches = [ ];
+
+    # Unset postPatch, as our version override breaks version-specific sed calls in the original package
+    postPatch = "";
+  })

nix/rocksdb-updater.nix

@@ -0,0 +1,14 @@
+{
+  perSystem =
+    { pkgs, ... }:
+    {
+      apps.update-rocksdb = {
+        type = "app";
+        program = pkgs.writeShellApplication {
+          name = "update-rocksdb";
+          runtimeInputs = [ pkgs.nix-update ];
+          text = "nix-update rocksdb -F --version branch";
+        };
+      };
+    };
+}