add file locks to prevent git checkout races

forc-pkg/Cargo.toml

@@ -10,6 +10,7 @@ description = "Building, locking, fetching and updating Sway projects as Forc pa
 
 [dependencies]
 anyhow = "1"
+fd-lock = "3.0.8"
 forc-tracing = { version = "0.31.3", path = "../forc-tracing" }
 forc-util = { version = "0.31.3", path = "../forc-util" }
 fuels-types = "0.31" 

forc-pkg/src/pkg.rs

@@ -7,6 +7,7 @@ use crate::{
     CORE, PRELUDE, STD,
 };
 use anyhow::{anyhow, bail, Context, Error, Result};
+use fd_lock::RwLock;
 use forc_util::{
     default_output_directory, find_file_name, git_checkouts_directory, kebab_to_snake_case,
     print_on_failure, print_on_success,
@@ -1609,11 +1610,20 @@ fn with_tmp_git_repo<F, O>(fetch_id: u64, name: &str, source: &SourceGit, f: F)
 where
     F: FnOnce(git2::Repository) -> Result<O>,
 {
-    // Clear existing temporary directory if it exists.
     let repo_dir = tmp_git_repo_dir(fetch_id, name, &source.repo);
-    if repo_dir.exists() {
-        let _ = std::fs::remove_dir_all(&repo_dir);
-    }
+
+    // Always clear existing temporary directory.
+    let _ = std::fs::remove_dir_all(&repo_dir);
+
+    let _ = std::fs::create_dir_all(&repo_dir);
+
+    let mut lock = RwLock::new(
+        fs::OpenOptions::new()
+            .write(true)
+            .create(true)
+            .open(&repo_dir.join(".forc-lock"))?,
+    );
+    let _ = lock.write()?;
 
     // Initialise the repository.
     let repo = git2::Repository::init(&repo_dir)
@@ -1811,10 +1821,17 @@ pub fn fetch_git(fetch_id: u64, name: &str, pinned: &SourceGitPinned) -> Result<
         // Change HEAD to point to the pinned commit.
         let id = git2::Oid::from_str(&pinned.commit_hash)?;
         repo.set_head_detached(id)?;
-        if path.exists() {
-            let _ = std::fs::remove_dir_all(&path);
-        }
-        std::fs::create_dir_all(&path)?;
+
+        let _ = std::fs::remove_dir_all(&path);
+
+        let _ = std::fs::create_dir_all(&path);
+        let mut lock = RwLock::new(
+            fs::OpenOptions::new()
+                .write(true)
+                .create(true)
+                .open(&path.join(".forc-lock"))?,
+        );
+        let _ = lock.write()?;
 
         // Checkout HEAD to the target directory.
         let mut checkout = git2::build::CheckoutBuilder::new();