From 424c6219e8c84a7b70b3213c248a33b027d74422 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Fri, 28 May 2021 16:35:36 +0300
Subject: [PATCH] fix: prevent build-time deadlock when building tests in
 release mode

---
 runtime/near-test-contracts/build.rs | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/runtime/near-test-contracts/build.rs b/runtime/near-test-contracts/build.rs
index 116c61cfbb5..1cf77c69589 100644
--- a/runtime/near-test-contracts/build.rs
+++ b/runtime/near-test-contracts/build.rs
@@ -1,5 +1,7 @@
+use std::path::Path;
+use std::path::PathBuf;
 use std::process::Command;
-use std::{fs, io, process};
+use std::{env, fs, io, process};
 
 fn main() {
     if let Err(err) = try_main() {
@@ -29,8 +31,9 @@ fn build_contract(dir: &str, args: &[&str], output: &str) -> io::Result<()> {
     cmd.current_dir(dir);
     check_status(cmd)?;
 
+    let target_dir = shared_target_dir().unwrap_or_else(|| format!("./{}/target", dir).into());
     fs::copy(
-        format!("./{}/target/wasm32-unknown-unknown/release/{}.wasm", dir, dir.replace('-', "_")),
+        target_dir.join(format!("wasm32-unknown-unknown/release/{}.wasm", dir.replace('-', "_"))),
         format!("./res/{}.wasm", output),
     )?;
     println!("cargo:rerun-if-changed=./{}/src/lib.rs", dir);
@@ -41,6 +44,10 @@ fn build_contract(dir: &str, args: &[&str], output: &str) -> io::Result<()> {
 fn cargo_build_cmd() -> Command {
     let mut res = Command::new("cargo");
     res.env("RUSTFLAGS", "-C link-arg=-s");
+    if let Some(target_dir) = shared_target_dir() {
+        res.env("CARGO_TARGET_DIR", target_dir);
+    }
+
     res.args(&["build", "--target=wasm32-unknown-unknown", "--release"]);
     res
 }
@@ -57,3 +64,14 @@ fn check_status(mut cmd: Command) -> io::Result<()> {
     }
     Ok(())
 }
+
+fn shared_target_dir() -> Option<PathBuf> {
+    let target_dir = env::var("CARGO_TARGET_DIR").ok()?;
+    // Avoid sharing the same target directory with the patent Cargo
+    // invocation, to avoid deadlock on the target dir.
+    //
+    // That is, this logic is needed for the case like the following:
+    //
+    //    CARGO_TARGET_DIR=/tmp cargo build -p near-test-contracts --release
+    Some(Path::new(&target_dir).join("near-test-contracts"))
+}