Improve flake compiler setup and CI integration

.github/workflows/depends.yml

@@ -27,8 +27,8 @@ jobs:
       - name: Checkout Bitcoin Repo
         uses: actions/checkout@v4
         with:
-          repository: willcl-ark/bitcoin
-          ref: cmake-dependency-provider
+          repository: bitcoin/bitcoin
+          ref: master
           path: bitcoin
           fetch-depth: 1
 
@@ -80,7 +80,7 @@ jobs:
 
       - name: Build bitcoin from depends
         run: |
-          nix develop --command bash -c "
+          nix develop .#depends --command bash -c "
             set -eux
 
             export CCACHE_DIR=${{ env.CCACHE_DIR }}
@@ -91,7 +91,7 @@ jobs:
             HOST_TRIPLET=\$(./depends/config.guess)
             export HOST_TRIPLET
             make -C depends -j\$(nproc) NO_QT=1
-            cmake -B build --toolchain \"depends/\$HOST_TRIPLET/toolchain.cmake\" -DCMAKE_PROJECT_TOP_LEVEL_INCLUDES=\"depends/\$HOST_TRIPLET/dependency_provider.cmake\"
+            cmake -B build --toolchain \"depends/\$HOST_TRIPLET/toolchain.cmake\"
             cmake --build build -j\$(nproc)
             ccache --show-stats
           "

.github/workflows/nix.yml

@@ -21,15 +21,19 @@ jobs:
         include:
           - system: x86_64-linux
             runner_label: ubuntu-latest
+            cores: 4
             cmake_flags:
           - system: aarch64-linux
             runner_label: ubuntu-24.04-arm
+            cores: 4
             cmake_flags:
           - system: x86_64-darwin
-            runner_label: macos-13
+            runner_label: macos-15-intel
+            cores: 4
             cmake_flags: -DWITH_USDT=OFF
           - system: aarch64-darwin
-            runner_label: macos-14
+            runner_label: macos-latest
+            cores: 3
             cmake_flags: -DWITH_USDT=OFF
 
     env:
@@ -85,7 +89,11 @@ jobs:
             set -eux
             export CCACHE_DIR=${{ env.CCACHE_DIR }}
             cd bitcoin
-            cmake -B build -DCMAKE_C_COMPILER_LAUNCHER=ccache -DCMAKE_CXX_COMPILER_LAUNCHER=ccache --preset dev-mode ${{ matrix.cmake_flags }}
-            cmake --build build -j$(nproc)
+            cmake -B build \
+              -DCMAKE_C_COMPILER_LAUNCHER=ccache \
+              -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \
+              --preset dev-mode \
+              ${{ matrix.cmake_flags }}
+            cmake --build build -j${{ matrix.cores }}
             ccache --show-stats
           "

flake.nix

@@ -3,38 +3,40 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.05";
+    nixpkgs-qt6.url = "github:NixOS/nixpkgs/0c0e48b0ec1af2d7f7de70f839de1569927fe4c8";
     flake-utils.url = "github:numtide/flake-utils";
   };
 
   outputs = {
     nixpkgs,
+    nixpkgs-qt6,
     flake-utils,
     ...
   }:
     flake-utils.lib.eachDefaultSystem (system: let
-      pkgs = import nixpkgs {inherit system;};
-      isLinux = pkgs.stdenv.isLinux;
-      isDarwin = pkgs.stdenv.isDarwin;
-      lib = pkgs.lib;
-
-      # Configure LLVM and python version for the environment
-      llvmVersion = "20";
-      pythonVersion = "13";
-
-      llvmPackages = pkgs."llvmPackages_${llvmVersion}";
-      llvmTools = {
-        inherit (llvmPackages) bintools clang clang-tools;
-        lldb = pkgs."lldb_${llvmVersion}";
+      # Overlay depends-matching version of qt6: https://github.com/bitcoin/bitcoin/blob/master/depends/packages/qt_details.mk#L1
+      qtPkgs = import nixpkgs-qt6 {inherit system;};
+      pkgs = import nixpkgs {
+        inherit system;
+        overlays = [
+          (final: prev: {
+            qt6 = qtPkgs.qt6;
+          })
+        ];
       };
+      inherit (pkgs) lib;
+      inherit (pkgs.stdenv) isLinux isDarwin;
+
+      python = pkgs.python313;
+      llvmPackages = pkgs.llvmPackages_20;
 
-      # Helper for platform-specific packages
-      platformPkgs = cond: pkgs:
-        if cond
-        then pkgs
-        else [];
+      # On Darwin use clang-20 otherwise use a gcc15 (and mold)-based standard env.
+      stdEnv =
+        if isDarwin
+        then llvmPackages.stdenv
+        else pkgs.stdenvAdapters.useMoldLinker pkgs.gcc15Stdenv;
 
-      # Use a single pythonEnv throughout and specifically in the devShell to make sure bcc is available.
-      pythonEnv = pkgs."python3${pythonVersion}".withPackages (ps:
+      pythonEnv = python.withPackages (ps:
         with ps;
           [
             flake8
@@ -43,7 +45,7 @@
             pyzmq
             vulture
           ]
-          ++ platformPkgs isLinux [
+          ++ lib.optionals isLinux [
             bcc
           ]);
 
@@ -52,59 +54,54 @@
         [
           bison
           ccache
+          clang-tools
           cmake
           curlMinimal
-          llvmTools.bintools
-          llvmTools.clang
-          llvmTools.clang-tools
           ninja
           pkg-config
-          qt6.wrapQtAppsHook # https://nixos.org/manual/nixpkgs/stable/#sec-language-qt
           xz
         ]
-        ++ platformPkgs isLinux [
+        ++ lib.optionals isLinux [
           libsystemtap
           linuxPackages.bcc
           linuxPackages.bpftrace
         ];
 
+      qtBuildInputs = with pkgs; [
+        qt6.qtbase # https://nixos.org/manual/nixpkgs/stable/#sec-language-qt
+        qt6.qttools
+      ];
+
       # Will exist in the runtime environment
-      buildInputs = with pkgs;
-        [
-          boost
-          capnproto
-          libevent
-          qrencode
-          qt6.qtbase # https://nixos.org/manual/nixpkgs/stable/#sec-language-qt
-          qt6.qttools
-          sqlite.dev
-          zeromq
-        ]
-        ++ platformPkgs isLinux [
-          libsystemtap
-          linuxPackages.bcc
-          linuxPackages.bpftrace
-        ];
+      buildInputs = with pkgs; [
+        boost
+        capnproto
+        libevent
+        qrencode
+        sqlite.dev
+        zeromq
+      ];
 
-      env = {
-        CMAKE_GENERATOR = "Ninja";
-        LD_LIBRARY_PATH = lib.makeLibraryPath [pkgs.capnproto];
-        LOCALE_ARCHIVE = lib.optionalString isLinux "${pkgs.glibcLocales}/lib/locale/locale-archive";
-      };
+      mkDevShell = nativeInputs: buildInputs:
+        (pkgs.mkShell.override {stdenv = stdEnv;}) {
+          inherit nativeBuildInputs buildInputs;
+          packages =
+            [
+              pythonEnv
+              pkgs.codespell
+              pkgs.hexdump
+            ]
+            ++ lib.optionals isLinux [pkgs.gdb]
+            ++ lib.optionals isDarwin [llvmPackages.lldb];
+
+          CMAKE_GENERATOR = "Ninja";
+          CMAKE_EXPORT_COMPILE_COMMANDS = 1;
+          LD_LIBRARY_PATH = lib.makeLibraryPath [pkgs.capnproto];
+          LOCALE_ARCHIVE = lib.optionalString isLinux "${pkgs.glibcLocales}/lib/locale/locale-archive";
+        };
     in {
-      # We use mkShelNoCC to avoid having Nix set up a gcc-based build environment
-      devShells.default = pkgs.mkShellNoCC {
-        inherit nativeBuildInputs buildInputs;
-        packages =
-          [
-            pythonEnv
-            pkgs.codespell
-            pkgs.hexdump
-          ]
-          ++ platformPkgs isLinux [pkgs.gdb]
-          ++ platformPkgs isDarwin [llvmTools.lldb];
-        inherit (env) CMAKE_GENERATOR LD_LIBRARY_PATH LOCALE_ARCHIVE;
-      };
+      devShells.default = mkDevShell (nativeBuildInputs ++ [pkgs.qt6.wrapQtAppsHook]) (buildInputs ++ qtBuildInputs);
+      devShells.depends = mkDevShell nativeBuildInputs qtBuildInputs;
 
       formatter = pkgs.alejandra;
     });