rust-bindgen: separate into unwrapped and wrapped

pkgs/development/tools/rust/bindgen/default.nix

···
-{ lib, fetchFromGitHub, rustPlatform, clang, rustfmt, writeTextFile
-, runtimeShell
-, bash
-}:
-
-rustPlatform.buildRustPackage rec {
-  pname = "rust-bindgen";
-  version = "0.59.2";
-
-  RUSTFLAGS = "--cap-lints warn"; # probably OK to remove after update
-
-  src = fetchFromGitHub {
-    owner = "rust-lang";
-    repo = pname;
-    rev = "v${version}";
-    sha256 = "sha256-bJYdyf5uZgWe7fQ80/3QsRV0qyExYn6P9UET3tzwPFs=";
-  };
-
-  cargoSha256 = "sha256-zhENlrqj611RkKDvpDtDFWc58wfQVamkJnpe2nvRieE=";
-
+{ rust-bindgen-unwrapped, bash, runCommand }:
+let
+  clang = rust-bindgen-unwrapped.clang;
+in
+runCommand "rust-bindgen-${rust-bindgen-unwrapped.version}"
+{
   #for substituteAll
-  libclang = clang.cc.lib; # use the same version of clang for cxxincludes and libclang
   inherit bash;
-
-  buildInputs = [ libclang ];
-
-  preConfigure = ''
-    export LIBCLANG_PATH="${lib.getLib libclang}/lib"
-  '';
-
-  postInstall = ''
-    mv $out/bin/{bindgen,.bindgen-wrapped};
-    export cincludes="$(< ${clang}/nix-support/cc-cflags) $(< ${clang}/nix-support/libc-cflags)"
-    export cxxincludes="$(< ${clang}/nix-support/libcxx-cxxflags)"
-    substituteAll ${./wrapper.sh} $out/bin/bindgen
-    chmod +x $out/bin/bindgen
-  '';
-
-  doCheck = true;
-  checkInputs =
-    let fakeRustup = writeTextFile {
-      name = "fake-rustup";
-      executable = true;
-      destination = "/bin/rustup";
-      text = ''
-        #!${runtimeShell}
-        shift
-        shift
-        exec "$@"
-      '';
-    };
-  in [
-    rustfmt
-    fakeRustup # the test suite insists in calling `rustup run nightly rustfmt`
-    clang
-  ];
-  preCheck = ''
-    # for the ci folder, notably
-    patchShebangs .
-  '';
+  unwrapped = rust-bindgen-unwrapped;
+  libclang = clang.cc.lib;
+} ''
+  mkdir -p $out/bin
+  export cincludes="$(< ${clang}/nix-support/cc-cflags) $(< ${clang}/nix-support/libc-cflags)"
+  export cxxincludes="$(< ${clang}/nix-support/libcxx-cxxflags)"
+  substituteAll ${./wrapper.sh} $out/bin/bindgen
+  chmod +x $out/bin/bindgen
+''
 
-  meta = with lib; {
-    description = "Automatically generates Rust FFI bindings to C (and some C++) libraries";
-    longDescription = ''
-      Bindgen takes a c or c++ header file and turns them into
-      rust ffi declarations.
-      As with most compiler related software, this will only work
-      inside a nix-shell with the required libraries as buildInputs.
-      This version of bindgen is wrapped with the required compiler flags
-      required to find the c and c++ standard libary of the input clang
-      derivation.
-    '';
-    homepage = "https://github.com/rust-lang/rust-bindgen";
-    license = with licenses; [ bsd3 ];
-    platforms = platforms.unix;
-    maintainers = with maintainers; [ johntitor ralith ];
-  };
-}

pkgs/development/tools/rust/bindgen/unwrapped.nix

···
+{ lib, fetchFromGitHub, rustPlatform, clang, rustfmt, writeTextFile
+, runtimeShell
+, bash
+}:
+
+rustPlatform.buildRustPackage rec {
+  pname = "rust-bindgen-unwrapped";
+  version = "0.59.2";
+
+  RUSTFLAGS = "--cap-lints warn"; # probably OK to remove after update
+
+  src = fetchFromGitHub {
+    owner = "rust-lang";
+    repo = "rust-bindgen";
+    rev = "v${version}";
+    sha256 = "sha256-bJYdyf5uZgWe7fQ80/3QsRV0qyExYn6P9UET3tzwPFs=";
+  };
+
+  cargoSha256 = "sha256-RKZY5vf6CSFaKweuuNkeFF0ZXlSUibAkcL/YhkE0MoQ=";
+
+  buildInputs = [ clang.cc.lib ];
+
+  preConfigure = ''
+    export LIBCLANG_PATH="${clang.cc.lib}/lib"
+  '';
+
+  doCheck = true;
+  checkInputs =
+    let fakeRustup = writeTextFile {
+      name = "fake-rustup";
+      executable = true;
+      destination = "/bin/rustup";
+      text = ''
+        #!${runtimeShell}
+        shift
+        shift
+        exec "$@"
+      '';
+    };
+  in [
+    rustfmt
+    fakeRustup # the test suite insists in calling `rustup run nightly rustfmt`
+    clang
+  ];
+  preCheck = ''
+    # for the ci folder, notably
+    patchShebangs .
+  '';
+
+  passthru = { inherit clang; };
+
+  meta = with lib; {
+    description = "Automatically generates Rust FFI bindings to C (and some C++) libraries";
+    longDescription = ''
+      Bindgen takes a c or c++ header file and turns them into
+      rust ffi declarations.
+      As with most compiler related software, this will only work
+      inside a nix-shell with the required libraries as buildInputs.
+      This version of bindgen is wrapped with the required compiler flags
+      required to find the c and c++ standard libary of the input clang
+      derivation.
+    '';
+    homepage = "https://github.com/rust-lang/rust-bindgen";
+    license = with licenses; [ bsd3 ];
+    platforms = platforms.unix;
+    maintainers = with maintainers; [ johntitor ralith ];
+  };
+}

pkgs/development/tools/rust/bindgen/wrapper.sh

···
 export LIBCLANG_PATH="@libclang@/lib"
 # shellcheck disable=SC2086
 # cxxflags and NIX_CFLAGS_COMPILE should be word-split
-exec -a "$0" @out@/bin/.bindgen-wrapped "$@" $sep $cxxflags @cincludes@ $NIX_CFLAGS_COMPILE
+exec -a "$0" @unwrapped@/bin/bindgen "$@" $sep $cxxflags @cincludes@ $NIX_CFLAGS_COMPILE
 # note that we add the flags after $@ which is incorrect. This is only for the sake
 # of simplicity.
 

pkgs/top-level/all-packages.nix

···
     inherit (darwin.apple_sdk.frameworks) CoreServices;
   };
   rust-analyzer = callPackage ../development/tools/rust/rust-analyzer/wrapper.nix { };
+  rust-bindgen-unwrapped = callPackage ../development/tools/rust/bindgen/unwrapped.nix { };
   rust-bindgen = callPackage ../development/tools/rust/bindgen { };
   rust-cbindgen = callPackage ../development/tools/rust/cbindgen {
     inherit (darwin.apple_sdk.frameworks) Security;