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language/tools/move-package/Cargo.toml

@@ -20,6 +20,7 @@ tempfile = "3.2.0"
 sha2 = "0.9.3"
 regex = "1.1.9"
 ptree = "0.4.0"
+once_cell = "1.7.2"
 
 move-binary-format = { path = "../../move-binary-format" }
 move-compiler = { path = "../../move-compiler" }

language/tools/move-package/src/lib.rs

@@ -15,8 +15,10 @@ use std::{
     collections::BTreeMap,
     io::Write,
     path::{Path, PathBuf},
+    sync::Mutex,
 };
 use structopt::*;
+use once_cell::sync::Lazy;
 
 use crate::{
     compilation::{
@@ -26,6 +28,19 @@ use crate::{
     source_package::{layout, manifest_parser},
 };
 
+pub(crate) static PACKAGE_MUTEX: Lazy<Mutex<()>> = Lazy::new(|| Mutex::new(()));
+
+#[macro_export]
+macro_rules! critical_section {
+    ($($code:stmt);*$(;)?) => {
+        {
+            let x = $crate::PACKAGE_MUTEX.lock().unwrap();
+            $($code);*
+            drop(x)
+        }
+    }
+}
+
 #[derive(Debug, StructOpt, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd)]
 #[structopt(
     name = "Move Package",

language/tools/move-package/src/resolution/resolution_graph.rs

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use crate::{
+    critical_section,
     resolution::digest::compute_digest,
     source_package::{
         layout::SourcePackageLayout,
@@ -352,7 +353,9 @@ impl ResolvingGraph {
         dep: Dependency,
         root_path: PathBuf,
     ) -> Result<(Renaming, ResolvingTable)> {
-        Self::download_and_update_if_repo(dep_name_in_pkg, &dep)?;
+        critical_section! {
+            Self::download_and_update_if_repo(dep_name_in_pkg, &dep)?;
+        }
         let (dep_package, dep_package_dir) =
             Self::parse_package_manifest(&dep, &dep_name_in_pkg, root_path)
                 .with_context(|| format!("While processing dependency '{}'", dep_name_in_pkg))?;