From 62df9d0ecddd45c9abdba4a3e6e013f72bdfed0c Mon Sep 17 00:00:00 2001
From: Nazar Mokrynskyi <nazar@mokrynskyi.com>
Date: Fri, 23 Sep 2022 12:36:33 +0300
Subject: [PATCH] Add support for `WASM_BUILD_CLEAN_TARGET` environment
 variable that cleans up unnecessary wasm build artifacts

---
 utils/wasm-builder/src/lib.rs          |  3 +++
 utils/wasm-builder/src/wasm_project.rs | 32 ++++++++++++++++++++++++--
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/utils/wasm-builder/src/lib.rs b/utils/wasm-builder/src/lib.rs
index fc86a06170a50..47e86b63cefd2 100644
--- a/utils/wasm-builder/src/lib.rs
+++ b/utils/wasm-builder/src/lib.rs
@@ -146,6 +146,9 @@ const WASM_BUILD_NO_COLOR: &str = "WASM_BUILD_NO_COLOR";
 /// Environment variable to set the toolchain used to compile the wasm binary.
 const WASM_BUILD_TOOLCHAIN: &str = "WASM_BUILD_TOOLCHAIN";
 
+/// Environment variable to instruct cleanup of `target` after successful wasm build.
+const WASM_BUILD_CLEAN_TARGET: &str = "WASM_BUILD_CLEAN_TARGET";
+
 /// Environment variable that makes sure the WASM build is triggered.
 const FORCE_WASM_BUILD_ENV: &str = "FORCE_WASM_BUILD";
 
diff --git a/utils/wasm-builder/src/wasm_project.rs b/utils/wasm-builder/src/wasm_project.rs
index 07219676413fc..f6acdfffe7a54 100644
--- a/utils/wasm-builder/src/wasm_project.rs
+++ b/utils/wasm-builder/src/wasm_project.rs
@@ -130,7 +130,7 @@ pub(crate) fn create_and_compile(
 		features_to_enable,
 	);
 
-	let profile = build_project(&project, default_rustflags, cargo_cmd);
+	let profile = build_project(&project, default_rustflags, &cargo_cmd);
 	let (wasm_binary, wasm_binary_compressed, bloaty) =
 		compact_wasm_file(&project, profile, project_cargo_toml, wasm_binary_name);
 
@@ -156,6 +156,10 @@ pub(crate) fn create_and_compile(
 		build_helper::warning!("Error while adjusting the mtime of the wasm binaries: {}", err)
 	}
 
+	if env::var(crate::WASM_BUILD_CLEAN_TARGET).is_ok() {
+		clean_target(&project, &cargo_cmd);
+	}
+
 	(final_wasm_binary, bloaty)
 }
 
@@ -602,7 +606,7 @@ fn offline_build() -> bool {
 fn build_project(
 	project: &Path,
 	default_rustflags: &str,
-	cargo_cmd: CargoCommandVersioned,
+	cargo_cmd: &CargoCommandVersioned,
 ) -> Profile {
 	let manifest_path = project.join("Cargo.toml");
 	let mut build_cmd = cargo_cmd.command();
@@ -651,6 +655,30 @@ fn build_project(
 	}
 }
 
+/// Build the project to create the WASM binary.
+fn clean_target(project: &Path, cargo_cmd: &CargoCommandVersioned) {
+	let manifest_path = project.join("Cargo.toml");
+	let mut build_cmd = cargo_cmd.command();
+
+	build_cmd
+		.arg("clean")
+		.arg(format!("--manifest-path={}", manifest_path.display()))
+		// Unset the `CARGO_TARGET_DIR` to prevent a cargo deadlock (cargo locks a target dir
+		// exclusive). The runner project is created in `CARGO_TARGET_DIR` and executing it will
+		// create a sub target directory inside of `CARGO_TARGET_DIR`.
+		.env_remove("CARGO_TARGET_DIR");
+
+	if super::color_output_enabled() {
+		build_cmd.arg("--color=always");
+	}
+
+	match build_cmd.status().map(|s| s.success()) {
+		Ok(true) => (),
+		// Use `process.exit(1)` to have a clean error output.
+		_ => process::exit(1),
+	}
+}
+
 /// Compact the WASM binary using `wasm-gc` and compress it using zstd.
 fn compact_wasm_file(
 	project: &Path,