Add Nix flake development shell by bresilla · Pull Request #617 · ros2-rust/ros2_rust

bresilla · 2026-03-26T14:01:38Z

Summary

add a Nix flake that provides a reproducible Rust + ROS 2 development shell for this workspace
include the generated flake.lock so the flake inputs are pinned and repeatable
configure the shell around ROS 2 Jazzy packages plus the Rust toolchain needed to build rclrs

Notes

the flake is currently set up for ROS 2 Jazzy
adapting it to another ROS distro should mostly be a small change in the distro selection, for example swapping jazzy to humble and updating the corresponding package set as needed

Verification

nix develop --impure -c cargo build

Copilot

Pull request overview

Adds a Nix flake to provide a reproducible Rust + ROS 2 (Jazzy) development shell for this workspace, with pinned inputs via flake.lock.

Changes:

Introduces flake.nix defining a devShell with Rust toolchain, ROS 2 Jazzy packages, and environment setup hooks.
Adds flake.lock to pin nixpkgs, nix-ros-overlay, rust-overlay, and flake-utils for repeatable environments.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 7 comments.

File	Description
flake.nix	Defines the Nix flake dev shell, ROS package environment, and shell hooks for building `rclrs` against ROS 2 Jazzy.
flake.lock	Pins flake inputs to specific revisions/hashes for reproducible builds.

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Copilot · 2026-03-26T14:06:39Z

flake.nix

+            #!/usr/bin/env sh
+            SETUPEOF
+                cat > "$synthetic_prefix/local_setup.bash" <<'SETUPEOF'
+            #!/usr/bin/env bash
+            SETUPEOF
+                cat > "$synthetic_prefix/local_setup.zsh" <<'SETUPEOF'
+            #!/usr/bin/env zsh


The heredoc body that writes local_setup.* is indented, so the #! line won’t start at byte 1 of the file. If these scripts are executed directly, they may fail with an exec format error. Write the heredoc contents without leading indentation so the shebang is valid.

Suggested change

#!/usr/bin/env sh

SETUPEOF

cat > "$synthetic_prefix/local_setup.bash" <<'SETUPEOF'

#!/usr/bin/env bash

SETUPEOF

cat > "$synthetic_prefix/local_setup.zsh" <<'SETUPEOF'

#!/usr/bin/env zsh

#!/usr/bin/env sh

SETUPEOF

cat > "$synthetic_prefix/local_setup.bash" <<'SETUPEOF'

#!/usr/bin/env bash

SETUPEOF

cat > "$synthetic_prefix/local_setup.zsh" <<'SETUPEOF'

#!/usr/bin/env zsh

Copilot · 2026-03-26T14:06:39Z

flake.nix

+
+                synthetic_prefix="$PWD/.nix-ament-prefix"


synthetic_prefix is created under $PWD (.nix-ament-prefix), which will modify the working tree and can leave untracked files in the repo. Consider placing this under a cache/temp location (e.g., $XDG_CACHE_HOME or $TMPDIR) to avoid polluting the workspace.

Suggested change

synthetic_prefix="$PWD/.nix-ament-prefix"

local base_dir

if [ -n "${XDG_CACHE_HOME:-}" ]; then

base_dir="$XDG_CACHE_HOME"

elif [ -n "${TMPDIR:-}" ]; then

base_dir="$TMPDIR"

else

base_dir="/tmp"

fi

synthetic_prefix="$base_dir/nix-ament-prefix"

Copilot · 2026-03-26T14:06:40Z

flake.nix

+  description = "ros flake";
+
+  inputs = {
+    nix-ros-overlay.url = "github:lopsided98/nix-ros-overlay/master";


The input URL github:lopsided98/nix-ros-overlay/master bakes the branch name into the flake. Since flake.lock already pins the exact revision, consider using github:lopsided98/nix-ros-overlay (or an explicit tag/rev) to avoid breakage if the default branch name changes.

Suggested change

nix-ros-overlay.url = "github:lopsided98/nix-ros-overlay/master";

nix-ros-overlay.url = "github:lopsided98/nix-ros-overlay";

Copilot · 2026-03-26T14:06:40Z

flake.nix

+
+  outputs =
+    { self, nixpkgs, rust-overlay, flake-utils, nix-ros-overlay, ... }:
+    flake-utils.lib.eachDefaultSystem (


flake-utils.lib.eachDefaultSystem will create outputs for macOS as well as Linux. Since the devShell is ROS 2–based (and most ROS Nix overlays are Linux-only), consider restricting to Linux systems explicitly (e.g., eachSystem [ "x86_64-linux" "aarch64-linux" ]) to avoid flake evaluation failures on unsupported platforms.

Suggested change

flake-utils.lib.eachDefaultSystem (

flake-utils.lib.eachSystem [ "x86_64-linux" "aarch64-linux" ] (

Should this be narrowed down to Linux and some specific architectures?

Yes. In eb61925 I narrowed the flake outputs to Linux only: x86_64-linux and aarch64-linux.

Copilot · 2026-03-26T14:06:40Z

flake.nix

+            export CC=clang
+            export CXX=clang++
+            export CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER=clang


CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER is hard-coded to the x86_64 target triple. This will be incorrect on aarch64-linux (and any non-x86_64 system) and can cause Cargo to ignore the intended linker or fail builds. Consider either removing this override or setting the linker env var based on the current target triple.

Copilot · 2026-03-26T14:06:40Z

flake.nix

+            ];
+
+          RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";


RUST_SRC_PATH is taken from pkgs.rust.packages.stable..., but this dev shell installs Rust via pkgs.rust-bin.stable.latest.... This can point to a different toolchain (or a missing src path) and break tools that rely on RUST_SRC_PATH. Prefer deriving RUST_SRC_PATH from the same rust-bin toolchain included in packages.

Copilot · 2026-03-26T14:06:40Z

flake.nix

+
+        pkgs = import nixpkgs {
+          inherit system overlays;
+          config.allowUnfree = true;


config.allowUnfree = true; enables unfree packages globally for this flake evaluation. If the dev shell doesn’t actually require unfree software, consider removing this or making it conditional to avoid surprising users/orgs with strict unfree policies.

Suggested change

config.allowUnfree = true;

config.allowUnfree = builtins.getEnv "ALLOW_UNFREE" == "1";

esteve

@bresilla awesome work! I've been playing with Nix lately and this is super convenient.

esteve · 2026-03-26T15:18:08Z

flake.nix

+              pkgs.colcon
+              (with rosDistro; buildEnv {
+                paths = [
+                  ros-core


I'd reduce the list of packages to ros-core and ros-base, adding moveit and ackermann-msgs seems out of scope.

ups, yeah, that's just a copy form another project :/

Reduced the package set in eb61925 to the narrower ROS environment and removed the out-of-scope extras. The shell now builds around ros-core, ros-base, cyclonedds, rmw-cyclonedds-cpp, and test-msgs.

esteve · 2026-03-26T15:19:31Z

flake.nix

+
+        pkgs = import nixpkgs {
+          inherit system overlays;
+          config.allowUnfree = true;


No need to allow unfree packages.

Removed allowUnfree in eb61925.

esteve · 2026-03-26T15:20:09Z

flake.nix

+
+  outputs =
+    { self, nixpkgs, rust-overlay, flake-utils, nix-ros-overlay, ... }:
+    flake-utils.lib.eachDefaultSystem (


Should this be narrowed down to Linux and some specific architectures?

bresilla · 2026-03-26T20:11:43Z

@esteve all your comments are valid. ahah, sorry, i thought i removed all unnecessary things when copied from another project. Will update it this weekend with those changes :)

bresilla · 2026-03-27T11:49:29Z

All addressed before the weekend could even arrive. :)

Add Nix flake development shell

a5fe0b0

Copilot AI review requested due to automatic review settings March 26, 2026 14:01

Copilot started reviewing on behalf of bresilla March 26, 2026 14:02 View session

Copilot AI reviewed Mar 26, 2026

View reviewed changes

esteve requested changes Mar 26, 2026

View reviewed changes

Address Nix flake review feedback

eb61925

bresilla requested a review from esteve March 27, 2026 11:50

-                synthetic_prefix="$PWD/.nix-ament-prefix"
+                local base_dir
+                if [ -n "${XDG_CACHE_HOME:-}" ]; then
+                    base_dir="$XDG_CACHE_HOME"
+                elif [ -n "${TMPDIR:-}" ]; then
+                    base_dir="$TMPDIR"
+                else
+                    base_dir="/tmp"
+                fi
+                synthetic_prefix="$base_dir/nix-ament-prefix"

	nix-ros-overlay.url = "github:lopsided98/nix-ros-overlay/master";
	nix-ros-overlay.url = "github:lopsided98/nix-ros-overlay";

	flake-utils.lib.eachDefaultSystem (
	flake-utils.lib.eachSystem [ "x86_64-linux" "aarch64-linux" ] (

		];

		RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";

	config.allowUnfree = true;
	config.allowUnfree = builtins.getEnv "ALLOW_UNFREE" == "1";

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bresilla commented Mar 26, 2026

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esteve Mar 26, 2026 •

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