feat: statically link libchat and rln via rust-bundle

Add rust-bundle, a single staticlib crate that depends on both libchat
and rln as rlibs. This ensures rustc links Rust std exactly once,
eliminating duplicate symbol errors on all platforms. Nim targets link
against liblogos_chat_bundle.a; Nix uses a bundleDrv instead of
separate libchat and rln derivations.

Reference: https://doc.rust-lang.org/reference/linkage.html#mixed-rust-and-foreign-codebases

.gitignore

@@ -4,6 +4,7 @@
 *.dSYM
 nimble.develop
 nimble.paths
+/rust-bundle
 
 
 /nimcache

Makefile

@@ -28,6 +28,7 @@ ifneq (,$(findstring MINGW,$(detected_OS)))
   detected_OS := Windows
 endif
 
+
 ##########
 ## Main ##
 ##########
@@ -73,38 +74,32 @@ NIM_PARAMS := $(NIM_PARAMS) -d:git_version=\"$(GIT_VERSION)\"
 ##################
 ## Dependencies ##
 ##################
-.PHONY: build-waku-librln
 
-LIBRLN_VERSION := v0.7.0
+CARGO_TARGET_DIR ?= rust-bundle/target
+RUST_BUNDLE_LIB := $(CARGO_TARGET_DIR)/release/librust_bundle.a
 
-ifeq ($(detected_OS),Windows)
-LIBRLN_FILE := rln.lib
-else
-LIBRLN_FILE := librln_$(LIBRLN_VERSION).a
-endif
-
-
-build-waku-librln:
-	@echo "Start building waku librln"
+# libchat and rln each embed Rust std when built as staticlibs; linking both
+# causes duplicate-symbol errors. rust-bundle/ links them as rlibs so std
+# is emitted once. [1]
+# [1] https://doc.rust-lang.org/reference/linkage.html#mixed-rust-and-foreign-codebases
+.PHONY: build-rust-bundle
+build-rust-bundle:
+	@echo "Building Rust bundle (libchat + rln)"
 	$(MAKE) -C vendor/nwaku librln
-	$(eval NIM_PARAMS += --passL:./vendor/nwaku/${LIBRLN_FILE} --passL:-lm)
-	@echo "Completed building librln"
+	CARGO_TARGET_DIR=$(CARGO_TARGET_DIR) cargo build --release --manifest-path rust-bundle/Cargo.toml
+	@echo "Bundle library: $(RUST_BUNDLE_LIB)"
 
 build-waku-nat:
 	@echo "Start building waku nat-libs"
 	$(MAKE) -C vendor/nwaku nat-libs
 	@echo "Completed building nat-libs"
 
-.PHONY: build-libchat
-build-libchat:
-	@echo "Start building libchat"
-	cd vendor/libchat && cargo build --release
-	@echo "Completed building libchat"
-
 .PHONY: tests
-tests: | build-waku-librln build-waku-nat build-libchat logos_chat.nims
+tests: | build-rust-bundle build-waku-nat logos_chat.nims
 	echo -e $(BUILD_MSG) "build/$@" && \
-		$(ENV_SCRIPT) nim tests $(NIM_PARAMS) logos_chat.nims
+		$(ENV_SCRIPT) nim tests $(NIM_PARAMS) \
+		--passL:$(RUST_BUNDLE_LIB) --passL:-lm \
+		logos_chat.nims
 
 
 ##########
@@ -112,9 +107,11 @@ tests: | build-waku-librln build-waku-nat build-libchat logos_chat.nims
 ##########
 
 # Ensure there is a nimble task with a name that matches the target
-tui bot_echo pingpong: | build-waku-librln build-waku-nat build-libchat logos_chat.nims
+tui bot_echo pingpong: | build-rust-bundle build-waku-nat logos_chat.nims
 	echo -e $(BUILD_MSG) "build/$@" && \
-	$(ENV_SCRIPT) nim $@ $(NIM_PARAMS) --path:src logos_chat.nims
+	$(ENV_SCRIPT) nim $@ $(NIM_PARAMS) \
+		--passL:$(RUST_BUNDLE_LIB) --passL:-lm \
+		--path:src logos_chat.nims
 
 ###########
 ## Library ##
@@ -132,9 +129,11 @@ endif
 LIBLOGOSCHAT := build/liblogoschat.$(LIBLOGOSCHAT_EXT)
 
 .PHONY: liblogoschat
-liblogoschat: | build-waku-librln build-waku-nat build-libchat logos_chat.nims
+liblogoschat: | build-rust-bundle build-waku-nat logos_chat.nims
 	echo -e $(BUILD_MSG) "$(LIBLOGOSCHAT)" && \
-	$(ENV_SCRIPT) nim liblogoschat $(NIM_PARAMS) --path:src logos_chat.nims && \
+	$(ENV_SCRIPT) nim liblogoschat $(NIM_PARAMS) \
+		--passL:$(RUST_BUNDLE_LIB) --passL:-lm \
+		--path:src logos_chat.nims && \
 	echo -e "\n\x1B[92mLibrary built successfully:\x1B[39m" && \
 	echo "  $(shell pwd)/$(LIBLOGOSCHAT)"
 

flake.nix

@@ -25,11 +25,11 @@
           overlays = [ rust-overlay.overlays.default ];
         };
         libchatDrv = pkgs.callPackage ./nix/libchat.nix {};
-        librln     = pkgs.callPackage ./nix/librln.nix {};
+        rustBundleDrv  = pkgs.callPackage ./nix/bundle.nix { src = self; };
       in {
         packages.default = pkgs.callPackage ./nix/default.nix {
           src = self;
-          inherit libchatDrv librln;
+          inherit rustBundleDrv;
         };
         devShells.default = pkgs.callPackage ./nix/shell.nix {
           inherit libchatDrv;

nix/bundle.nix

@@ -0,0 +1,34 @@
+{ lib, stdenv, rust-bin, makeRustPlatform, perl, pkg-config, cmake, src }:
+
+let
+  rustToolchain = rust-bin.fromRustupToolchainFile (src + "/vendor/libchat/rust_toolchain.toml");
+  rPlatform = makeRustPlatform {
+    cargo = rustToolchain;
+    rustc  = rustToolchain;
+  };
+in rPlatform.buildRustPackage {
+  pname = "rust-bundle";
+  version = "0.1.0";
+  inherit src;
+  cargoRoot = "rust-bundle";
+
+  cargoLock = {
+    lockFile = src + "/rust-bundle/Cargo.lock";
+    outputHashes = {
+      "chat-proto-0.1.0" = "sha256-aCl80VOIkd/GK3gnmRuFoSAvPBfeE/FKCaNlLt5AbUU=";
+    };
+  };
+
+  nativeBuildInputs = [ perl pkg-config cmake ];
+  doCheck = false;
+
+  buildAndTestSubdir = "rust-bundle";
+
+  installPhase = ''
+    runHook preInstall
+    mkdir -p $out/lib
+    find "$CARGO_TARGET_DIR" -name "librust_bundle.a" -path "*/release/*" -exec cp {} $out/lib/ \;
+    test -f $out/lib/librust_bundle.a
+    runHook postInstall
+  '';
+}

nix/default.nix

@@ -1,8 +1,7 @@
 { lib, stdenv, nim, which, pkg-config, writeScriptBin,
   openssl, miniupnpc, libnatpmp,
   src,         # logos-chat source (self from flake, with submodules=1)
-  libchatDrv,  # result of libchat.nix
-  librln }:    # result of librln.nix
+  rustBundleDrv }:  # result of bundle.nix
 
 # NOTE: this build requires git submodules to be present in src.
 # When fetching from GitHub use '?submodules=1#', e.g.:
@@ -14,21 +13,18 @@ assert lib.assertMsg ((src.submodules or false) == true)
 
 let
   revision = lib.substring 0 8 (src.rev or "dirty");
-  libExt = if stdenv.isDarwin then "dylib" else "so";
-  libchatPath = "${libchatDrv}/lib/liblibchat.${libExt}";
 in stdenv.mkDerivation {
   pname = "liblogoschat";
   version = "0.1.0";
   inherit src;
 
   NIMFLAGS = lib.concatStringsSep " " [
-    "--passL:vendor/nwaku/librln_v0.7.0.a"
+    "--passL:${rustBundleDrv}/lib/librust_bundle.a"
     "--passL:-lm"
     "-d:miniupnpcUseSystemLibs"
     "-d:libnatpmpUseSystemLibs"
     "--passL:-lminiupnpc"
     "--passL:-lnatpmp"
-    "-d:CONVERSATIONS_LIB:${libchatPath}"
     "-d:git_version=${revision}"
   ];
 
@@ -62,8 +58,6 @@ in stdenv.mkDerivation {
   '';
 
   preBuild = ''
-    # Place pre-built librln where the Nim linker expects it
-    cp ${librln}/lib/librln_v0.7.0.a vendor/nwaku/librln_v0.7.0.a
     mkdir -p build
   '';
 

nix/libchat.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, rust-bin, makeRustPlatform, perl, pkg-config, cmake }:
+{ rust-bin, makeRustPlatform, perl, pkg-config, cmake }:
 
 let
   rustToolchain = rust-bin.fromRustupToolchainFile ../vendor/libchat/rust_toolchain.toml;

nix/shell.nix

@@ -10,8 +10,7 @@ in pkgs.mkShell {
   ];
 
   shellHook = ''
-    export CONVERSATIONS_LIB="${libchatDrv}/lib/liblibchat.${libExt}"
-    echo "logos-chat dev shell. CONVERSATIONS_LIB=$CONVERSATIONS_LIB"
+    echo "logos-chat dev shell."
     echo "Build: make liblogoschat"
     echo "Nix build: nix build '.?submodules=1#'"
   '';

rust-bundle/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "rust-bundle"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+name = "rust_bundle"
+crate-type = ["staticlib"]
+
+[dependencies]
+libchat = { path = "../vendor/libchat/conversations" }
+rln = { path = "../vendor/nwaku/vendor/zerokit/rln", features = ["arkzkey"] }

rust-bundle/src/lib.rs

@@ -0,0 +1,4 @@
+// Force both rlibs into this staticlib.
+// Their #[no_mangle] pub extern "C" symbols are exported from librust_bundle.a.
+extern crate libchat;
+extern crate rln;

vendor/libchat

@@ -1 +1 @@
-Subproject commit 960bb195a13657a09fa2df66262b3b2ced738f30
+Subproject commit d006f20bcede00447fa4a09a42c0a18718057498