From ffa517e713a0313ce9c8d6dc5f9869395eaff7c9 Mon Sep 17 00:00:00 2001
From: AztecBot <tech@aztec-labs.com>
Date: Fri, 6 Mar 2026 19:25:12 +0000
Subject: [PATCH] fix: shared flock guard for rustup to prevent parallel build
 races

---
 avm-transpiler/bootstrap.sh | 10 +++++-----
 bootstrap.sh                | 12 ++++++++----
 noir/bootstrap.sh           | 22 +++++++++++++---------
 3 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/avm-transpiler/bootstrap.sh b/avm-transpiler/bootstrap.sh
index 768ce11eb08c..dc062d1e5cf2 100755
--- a/avm-transpiler/bootstrap.sh
+++ b/avm-transpiler/bootstrap.sh
@@ -13,13 +13,13 @@ function build_native {
   echo_header "avm-transpiler build_native"
   artifact=avm-transpiler-$hash.tar.gz
   if ! cache_download $artifact; then
-    # Serialize cargo/rustup operations to avoid race conditions when running parallel builds
-    # Cargo may trigger rustup to install components (rust-src, etc.) in shared directories
+    # Serialize cargo/rustup operations to avoid race conditions with noir build
+    # which may run in parallel and share the same RUSTUP_HOME/CARGO_HOME.
     (
       flock -x 200
       denoise "cargo build --release --locked --bin avm-transpiler"
       denoise "cargo build --release --locked --lib"
-    ) 200>/tmp/rustup-avm-transpiler.lock
+    ) 200>/tmp/rustup.lock
 
     denoise "cargo fmt --check"
     denoise "cargo clippy"
@@ -54,7 +54,7 @@ function build_cross {
         ;;
     esac
 
-    # Serialize rustup operations to avoid race conditions when running parallel builds
+    # Serialize rustup operations to avoid race conditions with noir build
     (
       flock -x 200
       if ! command -v cargo-zigbuild >/dev/null 2>&1; then
@@ -65,7 +65,7 @@ function build_cross {
         echo "Installing Rust target: $rust_target"
         rustup target add "$rust_target"
       fi
-    ) 200>/tmp/rustup-avm-transpiler.lock
+    ) 200>/tmp/rustup.lock
 
     cargo zigbuild --release --target "$rust_target" --lib
 
diff --git a/bootstrap.sh b/bootstrap.sh
index cdd88480cebb..3363f48fb81a 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -102,10 +102,14 @@ function check_toolchains {
   fi
   if ! rustup show | grep $rust_version > /dev/null; then
     if [ "${CI:-0}" -eq 1 ]; then
-      echo "Attempting install of required Rust version $rust_version"
-      rustup self update 2>/dev/null || true
-      rustup toolchain install $rust_version
-      rustup default $rust_version
+      # Serialize rustup operations to avoid race conditions with parallel builds.
+      (
+        flock -x 200
+        echo "Attempting install of required Rust version $rust_version"
+        rustup self update 2>/dev/null || true
+        rustup toolchain install $rust_version
+        rustup default $rust_version
+      ) 200>/tmp/rustup.lock
     else
       # Cargo will download necessary version of rust at runtime but warn to alert that an update to the build-image
       # is desirable.
diff --git a/noir/bootstrap.sh b/noir/bootstrap.sh
index 91515a2005e4..4fd19781f16a 100755
--- a/noir/bootstrap.sh
+++ b/noir/bootstrap.sh
@@ -77,15 +77,19 @@ function build_packages {
 
 function install_deps {
   set -euo pipefail
-  # TODO: Move to build image?
-  if ! command -v cargo-binstall &>/dev/null; then
-    curl -L --proto '=https' --tlsv1.2 -sSf https://raw.githubusercontent.com/cargo-bins/cargo-binstall/main/install-from-binstall-release.sh | bash
-  fi
-  if ! command -v just &>/dev/null; then
-    cargo-binstall just --version 1.42.4 -y --secure
-  fi
-  just --justfile ./noir-repo/justfile install-rust-tools
-  just --justfile ./noir-repo/justfile install-js-tools
+  # Serialize rustup/cargo-binstall operations to avoid race conditions with avm-transpiler
+  # which may run in parallel and share the same RUSTUP_HOME/CARGO_HOME.
+  (
+    flock -x 200
+    if ! command -v cargo-binstall &>/dev/null; then
+      curl -L --proto '=https' --tlsv1.2 -sSf https://raw.githubusercontent.com/cargo-bins/cargo-binstall/main/install-from-binstall-release.sh | bash
+    fi
+    if ! command -v just &>/dev/null; then
+      cargo-binstall just --version 1.42.4 -y --secure
+    fi
+    just --justfile ./noir-repo/justfile install-rust-tools
+    just --justfile ./noir-repo/justfile install-js-tools
+  ) 200>/tmp/rustup.lock
 }
 
 export -f build_native build_packages install_deps