remove bash -lc

npm_install.py

@@ -584,43 +584,41 @@ def install_node_and_yarn(node_pkg: str):
         os.symlink("/usr/bin/yarnpkg","/usr/bin/yarn")
 
 def _build_frontend(src_frontend: Path, dest_frontend: Path):
-    def _which(cmd: str) -> bool:
-        import shutil as _s
-        return _s.which(cmd) is not None
+
+    def _semver(s: str) -> bool:
+        return bool(re.match(r"^\d+(?:\.\d+){1,3}$", (s or "").strip()))
 
     def _good_yarn(cmd: str) -> bool:
-        out = (run_out([cmd, "--version"], check=False) or "").strip()
-        return bool(re.match(r"^\d+(?:\.\d+){1,3}$", out))
+        v = (run_out([cmd, "--version"], check=False) or "").strip()
+        return _semver(v)
 
-    yarn = None
-    for cand in ("yarn", "yarnpkg"):
-        if _which(cand) and _good_yarn(cand):
-            yarn = cand
-            break
-    if not yarn:
-        run(["corepack", "enable"], check=False)
-        run(["corepack", "prepare", "yarn@stable", "--activate"], check=False)
-        for cand in ("yarn", "yarnpkg"):
-            if _which(cand) and _good_yarn(cand):
-                yarn = cand
-                break
-    if not yarn:
+    yarn_cmd = None
+    if shutil.which("yarn") and _good_yarn("yarn"):
+        yarn_cmd = ["yarn"]
+    elif shutil.which("yarnpkg") and _good_yarn("yarnpkg"):
+        yarn_cmd = ["yarnpkg"]
+    elif shutil.which("npm"):
+        if (run_out(["npm", "--version"], check=False) or "").strip():
+            yarn_cmd = ["npm", "exec", "--yes", "yarn@stable"]
+    if not yarn_cmd:
         raise RuntimeError("No yarn in system")
 
     with step("Installing frontend dependencies (yarn)"):
         os.environ["NODE_ENV"] = "development"
         os.chdir(src_frontend)
-        cache_dir = (run_out([yarn, "cache", "dir"], check=False) or "").strip()
+
+        cache_dir = (run_out(yarn_cmd + ["cache", "dir"], check=False) or "").strip()
         if cache_dir and not Path(cache_dir).exists():
             Path(cache_dir).mkdir(parents=True, exist_ok=True)
 
-        run([yarn, "cache", "clean"], check=False)
-        run([yarn, "install"])
+        run(yarn_cmd + ["cache", "clean"], check=False)
+
+        run(yarn_cmd + ["install"])
 
     with step("Building frontend (yarn build)"):
         env = os.environ.copy()
         env["NODE_OPTIONS"] = "--openssl-legacy-provider"
-        run([yarn, "build"], env=env)
+        run(yarn_cmd + ["build"], env=env)
 
     with step("Copying frontend artifacts"):
         shutil.copytree(src_frontend / "dist", dest_frontend, dirs_exist_ok=True)