Use native import for Pyodide module

build.sh

@@ -13,6 +13,7 @@ jupyter lite build --contents content --output-dir dist
 python3 - <<'PY'
 import hashlib
 import json
+import re
 import shutil
 from pathlib import Path
 
@@ -29,6 +30,23 @@ kernel_settings = config["jupyter-config-data"]["litePluginSettings"][
 ]
 kernel_settings["pyodideUrl"] = f"./static/pyodide/{versioned_module.name}"
 config_path.write_text(json.dumps(config, indent=2) + "\n")
+
+kernel_extension_dir = Path(
+    "dist/extensions/@jupyterlite/pyodide-kernel-extension/static"
+)
+load_pyodide_pattern = re.compile(
+    r"\(await ([A-Za-z_$][\w$]*|__webpack_require__)\(476\)\(([A-Za-z_$][\w$]*)\)\)\.loadPyodide"
+)
+patched_files = []
+for path in kernel_extension_dir.glob("*.js"):
+    source = path.read_text()
+    patched = load_pyodide_pattern.sub(r"(await import(\2)).loadPyodide", source)
+    if patched != source:
+        path.write_text(patched)
+        patched_files.append(path.name)
+
+if not patched_files:
+    raise SystemExit("No Pyodide dynamic import bundle entry was patched")
 PY
 find content/ -type f -exec cat {} \; | sha256sum | cut -d' ' -f1 > content-hash.txt
 HASH=$(cat content-hash.txt)

tests/test_notebooks_pyodide.py

@@ -51,6 +51,17 @@ def test_configured_pyodide_module_exists():
   assert (DIST / pyodide_url.removeprefix("./")).exists()
 
 
+def test_pyodide_kernel_uses_native_dynamic_import():
+  extension_dir = DIST / "extensions" / "@jupyterlite" / "pyodide-kernel-extension" / "static"
+  js_files = list(extension_dir.glob("*.js"))
+  assert js_files
+  bundle_source = "\n".join(path.read_text(encoding="utf8") for path in js_files)
+  assert ".endsWith(\".mjs\")?t=(await import(" in bundle_source
+  assert "(476)(r)).loadPyodide" not in bundle_source
+  assert "(476)(n)).loadPyodide" not in bundle_source
+  assert "(476)(s)).loadPyodide" not in bundle_source
+
+
 def _execute_notebook(notebook_path: Path, *, cells: int | None = None, timeout: int = 600) -> None:
   """Execute a notebook using the local CPython kernel.