From cd53a63c4fa348fe54827789f883f71b923f83d9 Mon Sep 17 00:00:00 2001
From: Austin Seipp <aseipp@pobox.com>
Date: Sat, 24 Feb 2024 17:35:17 -0600
Subject: [PATCH 1/3] nix: s/rust-version/ourRustVersion/g

This naming is just more consistent with the surrounding code.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
---
 flake.nix | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/flake.nix b/flake.nix
index cdbf1e785b..9a1caa8ee6 100644
--- a/flake.nix
+++ b/flake.nix
@@ -35,11 +35,11 @@
             pkgs.lib.all (re: builtins.match re relPath == null) regexes;
         };
 
-      rust-version = pkgs.rust-bin.stable."1.76.0".default;
+      ourRustVersion = pkgs.rust-bin.stable."1.76.0".default;
 
       ourRustPlatform = pkgs.makeRustPlatform {
-        rustc = rust-version;
-        cargo = rust-version;
+        rustc = ourRustVersion;
+        cargo = ourRustVersion;
       };
 
       # these are needed in both devShell and buildInputs
@@ -137,14 +137,14 @@
       devShells.default = pkgs.mkShell {
         buildInputs = with pkgs; [
           # The CI checks against the latest nightly rustfmt, so we should too.
-          # NOTE (aseipp): include this FIRST before the rust-version override
-          # below; otherwise, it will be overridden by the rust-version and
+          # NOTE (aseipp): include this FIRST before the ourRustVersion override
+          # below; otherwise, it will be overridden by the ourRustVersion and
           # we'll get stable rustfmt instead.
           (rust-bin.selectLatestNightlyWith (toolchain: toolchain.rustfmt))
 
           # Using the minimal profile with explicit "clippy" extension to avoid
           # two versions of rustfmt
-          (rust-version.override {
+          (ourRustVersion.override {
             extensions = [
               "rust-src" # for rust-analyzer
               "clippy"

From 84b6ce53ba06f522db00f947fec62c018c54b7de Mon Sep 17 00:00:00 2001
From: Austin Seipp <aseipp@pobox.com>
Date: Sat, 24 Feb 2024 17:41:50 -0600
Subject: [PATCH 2/3] nix: fix nix-on-macOS build

When the `jj-proc-macros` crate was introduced, it triggered an underlying
bug in `nextest`, which is the test harness we use in the Nix build. This is
upstream Nextest bug 267. The long and short of it is that `rustc` fails to
find needed libraries whenever the proc macros are loaded.

This can easily be worked around however, by setting
`DYLD_FALLBACK_LIBRARY_PATH` to an appropriate value in the devShell and in the
`preCheck` phase of the main expression.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
---
 flake.nix | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/flake.nix b/flake.nix
index 9a1caa8ee6..5a0544268f 100644
--- a/flake.nix
+++ b/flake.nix
@@ -49,6 +49,12 @@
         libiconv
       ];
 
+      # work around https://github.com/nextest-rs/nextest/issues/267
+      # this needs to exist in both the devShell and preCheck phase!
+      darwinNextestHack = pkgs.lib.optionalString pkgs.stdenv.isDarwin ''
+        export DYLD_FALLBACK_LIBRARY_PATH=$(${ourRustVersion}/bin/rustc --print sysroot)/lib
+      '';
+      
       # NOTE (aseipp): on Linux, go ahead and use mold by default to improve
       # link times a bit; mostly useful for debug build speed, but will help
       # over time if we ever get more dependencies, too
@@ -97,7 +103,10 @@
           NIX_JJ_GIT_HASH = self.rev or "";
           CARGO_INCREMENTAL = "0";
 
-          preCheck = "export RUST_BACKTRACE=1";
+          preCheck = ''
+            export RUST_BACKTRACE=1
+          '' + darwinNextestHack;
+
           postInstall = ''
             $out/bin/jj util mangen > ./jj.1
             installManPage ./jj.1
@@ -181,7 +190,7 @@
           export LIBSSH2_SYS_USE_PKG_CONFIG=1
         '' + pkgs.lib.optionalString useMoldLinker ''
           export RUSTFLAGS="-C link-arg=-fuse-ld=mold"
-        '';
+        '' + darwinNextestHack;
       };
     }));
 }

From a4321d80f6ab5d0a00152e7273ca7239934c1fc1 Mon Sep 17 00:00:00 2001
From: Austin Seipp <aseipp@pobox.com>
Date: Sat, 24 Feb 2024 17:55:58 -0600
Subject: [PATCH 3/3] github: add nix-on-macOS to the CI matrix

The aarch64-darwin macOS runners are actually quite speedy, often the fastest
builders anyway. With the recent improvements to the Nix CI speed in 3f7b5a75e,
this shouldn't be a bottleneck, and will catch build regressions.
---
 .github/workflows/{nix-linux.yml => build-nix.yml} | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)
 rename .github/workflows/{nix-linux.yml => build-nix.yml} (78%)

diff --git a/.github/workflows/nix-linux.yml b/.github/workflows/build-nix.yml
similarity index 78%
rename from .github/workflows/nix-linux.yml
rename to .github/workflows/build-nix.yml
index 288ef4be22..2b805b86ad 100644
--- a/.github/workflows/nix-linux.yml
+++ b/.github/workflows/build-nix.yml
@@ -1,4 +1,4 @@
-name: Nix on Linux
+name: nix
 
 on:
   push:
@@ -10,9 +10,14 @@ permissions: read-all
 
 jobs:
   nix:
-    runs-on: ubuntu-latest
-    name: nix-build
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-14]
+    runs-on: ${{ matrix.os }}
     timeout-minutes: 15 # NOTE (aseipp): keep in-sync with the build.yml timeout limit
+
+    name: flake check
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with: