feat: explicitly use hoisted linker for bun install

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/tests/bun_jobs.rs

@@ -1191,6 +1191,49 @@ export function main(name: string) {
     Ok(())
 }
 
+// ============================================================================
+// NPM Dependency Tests
+// ============================================================================
+
+#[sqlx::test(fixtures("base"))]
+async fn test_bun_job_with_cowsay_dep(db: Pool<Postgres>) -> anyhow::Result<()> {
+    initialize_tracing().await;
+    let server = ApiServer::start(db.clone()).await?;
+    let port = server.addr.port();
+
+    let content = r#"
+import * as cowsay from "cowsay";
+
+export function main() {
+    return cowsay.say({ text: "hoisted" });
+}
+"#
+    .to_owned();
+
+    let job = JobPayload::Code(RawCode {
+        hash: None,
+        content,
+        path: None,
+        language: ScriptLang::Bun,
+        lock: None,
+        concurrency_settings:
+            windmill_common::runnable_settings::ConcurrencySettings::default().into(),
+        debouncing_settings: windmill_common::runnable_settings::DebouncingSettings::default(),
+        cache_ttl: None,
+        cache_ignore_s3_path: None,
+        dedicated_worker: None,
+    });
+
+    let result = run_job_in_new_worker_until_complete(&db, false, job, port)
+        .await
+        .json_result()
+        .unwrap();
+
+    let result_str = result.as_str().unwrap();
+    assert!(result_str.contains("hoisted"), "cowsay output should contain 'hoisted'");
+    Ok(())
+}
+
 /// Tests for RELATIVE_BUN_BUILDER (loader_builder.bun.js)
 /// These tests verify Bun's behavior for import scanning and package.json generation.
 /// Purpose: Catch regressions when upgrading Bun versions.

backend/windmill-worker/src/bun_executor.rs

@@ -342,7 +342,7 @@ pub async fn install_bun_lockfile(
 ) -> Result<()> {
     let mut child_cmd = Command::new(if npm_mode { &*NPM_PATH } else { &*BUN_PATH });
 
-    let mut args = vec!["install", "--save-text-lockfile"];
+    let mut args = vec!["install", "--save-text-lockfile", "--linker", "hoisted"];
 
     let no_cache = !npm_mode && *BUN_NO_CACHE;
 

backend/windmill-worker/src/prepare_deps.rs

@@ -462,7 +462,7 @@ pub async fn prepare_deps_standalone(code: &str, language: &str) -> PrepareRespo
         .current_dir(&job_dir)
         .env_clear()
         .envs(common_bun_proc_envs)
-        .args(vec!["install"])
+        .args(vec!["install", "--linker", "hoisted"])
         .stdout(Stdio::piped())
         .stderr(Stdio::piped())
         .output()