rustfmt: use the src as defined by the git submodule in rust

This commit makes sure rustc and rustfmt are compatible by setting
rustfmt's src to the rustfmt git submodule as defined in:

https://github.com/rust-lang/rust/tree/1.36.0/src/tools

4 files changed, 91 insertions, 35 deletions

diff --git a/pkgs/development/compilers/rust/default.nix b/pkgs/development/compilers/rust/default.nix
index 0e3de0c4ab98..d4f2f50ceee6 100644
--- a/pkgs/development/compilers/rust/default.nix
+++ b/pkgs/development/compilers/rust/default.nix
@@ -59,6 +59,7 @@
         pkgsBuildHost = pkgsBuildBuild // { targetPackages.stdenv = llvmPackages_5.stdenv; };
         pkgsBuildTarget = pkgsBuildTarget // { targetPackages.stdenv = llvmPackages_5.stdenv; };
       });
+      rustfmt = self.callPackage ./rustfmt.nix { inherit Security; };
       cargo = self.callPackage ./cargo.nix {
         # Use boot package set to break cycle
         rustPlatform = bootRustPlatform;
diff --git a/pkgs/development/compilers/rust/rustfmt.nix b/pkgs/development/compilers/rust/rustfmt.nix
new file mode 100644
index 000000000000..62a6ccbbef17
--- /dev/null
+++ b/pkgs/development/compilers/rust/rustfmt.nix
@@ -0,0 +1,89 @@
+{ stdenv, rustPlatform, rustc, Security }:
+
+rustPlatform.buildRustPackage rec {
+  name = "rustfmt-${version}";
+  inherit (rustc) version src;
+
+  # the rust source tarball already has all the dependencies vendored, no need to fetch them again
+  cargoVendorDir = "vendor";
+  preBuild = "pushd src/tools/rustfmt";
+  postBuild = "popd";
+
+  buildInputs = stdenv.lib.optional stdenv.isDarwin Security;
+
+  # As of 1.0.0 and rustc 1.30 rustfmt requires a nightly compiler
+  RUSTC_BOOTSTRAP = 1;
+
+  # Without disabling the test the build fails with:
+  #
+  #   Compiling rustc_llvm v0.0.0 (/private/tmp/nix-build-rustfmt-1.36.0.drv-0/rustc-1.36.0-src/src/librustc_llvm)
+  #   ...
+  #   error: failed to run custom build command for `rustc_llvm v0.0.0
+  #     (/private/tmp/nix-build-rustfmt-1.36.0.drv-0/rustc-1.36.0-src/src/librustc_llvm)`
+  #
+  #   Caused by:
+  #     process didn't exit successfully:
+  #       `/private/tmp/nix-build-rustfmt-1.36.0.drv-0/rustc-1.36.0-src/target/debug/build/rustc_llvm-4d3eb1eff32fd46b/build-script-build` (exit code: 101)
+  #   --- stdout
+  #   cargo:rerun-if-env-changed=REAL_LIBRARY_PATH_VAR
+  #   cargo:rerun-if-env-changed=REAL_LIBRARY_PATH
+  #
+  #   --- stderr
+  #   thread 'main' panicked at 'REAL_LIBRARY_PATH_VAR', src/libcore/option.rs:1036:5
+  #   note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+  #
+  # Setting the following:
+  #
+  #   # This mimics https://github.com/rust-lang/rust/blob/1.36.0/src/bootstrap/util.rs#L58:L70
+  #   REAL_LIBRARY_PATH_VAR =
+  #     if stdenv.isDarwin then "DYLD_LIBRARY_PATH"
+  #     else "LD_LIBRARY_PATH";
+  #
+  # Results in:
+  #
+  #   Compiling rustc_llvm v0.0.0 (/private/tmp/nix-build-rustfmt-1.36.0.drv-0/rustc-1.36.0-src/src/librustc_llvm)
+  #   ...
+  #   error: failed to run custom build command for `rustc_llvm v0.0.0 (/private/tmp/nix-build-rustfmt-1.36.0.drv-0/rustc-1.36.0-src/src/librustc_llvm)`
+  #
+  #   Caused by:
+  #     process didn't exit successfully: `/private/tmp/nix-build-rustfmt-1.36.0.drv-0/rustc-1.36.0-src/target/debug/build/rustc_llvm-4d3eb1eff32fd46b/build-script-build` (exit code: 1)
+  #   --- stdout
+  #   cargo:rerun-if-env-changed=REAL_LIBRARY_PATH_VAR
+  #   cargo:rerun-if-env-changed=REAL_LIBRARY_PATH
+  #   cargo:rerun-if-changed=llvm-config
+  #   cargo:rerun-if-env-changed=LLVM_CONFIG
+  #
+  #
+  #   failed to execute command: "llvm-config" "--version"
+  #   error: No such file or directory (os error 2)
+  #
+  # Adding `llvmSharedForBuild` to rustc's `passthru` and adding
+  # `rustc.llvmSharedForBuild` to the `buildInputs` fixes this but then the
+  # build fails lateron with:
+  #
+  #   Compiling rustc_llvm v0.0.0 (/private/tmp/nix-build-rustfmt-1.36.0.drv-0/rustc-1.36.0-src/src/librustc_llvm)
+  #   ...
+  #   error[E0658]: use of unstable library feature 'rustc_private': this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via `Cargo.toml` instead?
+  #    --> src/librustc_llvm/lib.rs:9:1
+  #     |
+  #   9 | extern crate rustc_cratesio_shim;
+  #     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  #     |
+  #     = note: for more information, see https://github.com/rust-lang/rust/issues/27812
+  #     = help: add #![feature(rustc_private)] to the crate attributes to enable
+  #
+  #   error: aborting due to previous error
+  #
+  #   For more information about this error, try `rustc --explain E0658`.
+  #
+  #   error: Could not compile `rustc_llvm`.
+  doCheck = false;
+
+  meta = with stdenv.lib; {
+    description = "A tool for formatting Rust code according to style guidelines";
+    homepage = https://github.com/rust-lang-nursery/rustfmt;
+    license = with licenses; [ mit asl20 ];
+    maintainers = with maintainers; [ globin basvandijk ];
+    platforms = platforms.all;
+  };
+}
diff --git a/pkgs/development/tools/rust/rustfmt/default.nix b/pkgs/development/tools/rust/rustfmt/default.nix
deleted file mode 100644
index b98ab0dc74d7..000000000000
--- a/pkgs/development/tools/rust/rustfmt/default.nix
+++ /dev/null
@@ -1,34 +0,0 @@
-{ stdenv, fetchFromGitHub, rustPlatform, darwin }:
-
-rustPlatform.buildRustPackage rec {
-  name = "rustfmt-${version}";
-  version = "1.2.2";
-
-  src = fetchFromGitHub {
-    owner = "rust-lang";
-    repo = "rustfmt";
-    rev = "v${version}";
-    sha256 = "1k9p6sp8q87flx9vzg46880ir7likvbydai3g6q76278h86rn0v8";
-  };
-
-  cargoSha256 = "08x6vy5v2vgrk3gsw3qcvv52a7hifsgcsnsg1phlk1ikaff21y4z";
-
-  buildInputs = stdenv.lib.optional stdenv.isDarwin darwin.apple_sdk.frameworks.Security;
-
-  # As of 1.0.0 and rustc 1.30 rustfmt requires a nightly compiler
-  RUSTC_BOOTSTRAP = 1;
-
-  # we run tests in debug mode so tests look for a debug build of
-  # rustfmt. Anyway this adds nearly no compilation time.
-  preCheck = ''
-    cargo build
-  '';
-
-  meta = with stdenv.lib; {
-    description = "A tool for formatting Rust code according to style guidelines";
-    homepage = https://github.com/rust-lang-nursery/rustfmt;
-    license = with licenses; [ mit asl20 ];
-    maintainers = [ maintainers.globin ];
-    platforms = platforms.all;
-  };
-}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 5e9eb55dbab7..e5f86984b17d 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -8243,7 +8243,7 @@ in
   rls = callPackage ../development/tools/rust/rls {
     inherit (darwin.apple_sdk.frameworks) CoreFoundation Security;
   };
-  rustfmt = callPackage ../development/tools/rust/rustfmt { };
+  rustfmt = rustPackages.rustfmt;
   rustracer = callPackage ../development/tools/rust/racer {
     inherit (darwin.apple_sdk.frameworks) Security;
   };