Add --clear flag to lock to clear lockfile metadata

Clears lockfile metadata from the Jupyter notebook with the addition of
the `--clear` to the command.

src/juv/__init__.py

@@ -461,17 +461,22 @@ def remove(
 
 @cli.command()
 @click.argument("file", type=click.Path(exists=True), required=True)
+@click.option("--clear", is_flag=True, help="Clear the lockfile contents.")
 def lock(
     *,
     file: str,
+    clear: bool,
 ) -> None:
     """Update the notebooks's lockfile."""
     from ._lock import lock
 
     try:
-        lock(path=Path(file))
+        lock(path=Path(file), clear=clear)
         path = os.path.relpath(Path(file).resolve(), Path.cwd())
-        rich.print(f"Locked `[cyan]{path}[/cyan]`")
+        if clear:
+            rich.print(f"Cleared lockfile `[cyan]{path}[/cyan]`")
+        else:
+            rich.print(f"Locked `[cyan]{path}[/cyan]`")
     except RuntimeError as e:
         rich.print(e, file=sys.stderr)
         sys.exit(1)

src/juv/_lock.py

@@ -9,11 +9,14 @@
 from ._uv import uv
 
 
-def lock(
-    path: Path,
-) -> None:
+def lock(*, path: Path, clear: bool) -> None:
     notebook = jupytext.read(path, fmt="ipynb")
 
+    if clear:
+        notebook.get("metadata", {}).pop("uv.lock", None)
+        write_ipynb(notebook, path)
+        return
+
     cell = find(
         lambda cell: (
             cell["cell_type"] == "code"

tests/test_juv.py

@@ -1208,9 +1208,7 @@ def test_tree_updates_lock(
 """)
 
     notebook.cells[0] = new_code_cell("""# /// script
-# dependencies = []
-# requires-python = ">=3.8"
-# ///
+# dependencies = [] requires-python = ">=3.8" ///
 """)
     write_ipynb(notebook, tmp_path / "test.ipynb")
     invoke(["tree", "test.ipynb"])
@@ -1221,3 +1219,38 @@ def test_tree_updates_lock(
 [options]
 exclude-newer = "2023-02-01T02:00:00Z"
 """)
+
+
+def test_clear_lock(
+    tmp_path: pathlib.Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.chdir(tmp_path)
+
+    invoke(["init", "test.ipynb"])
+    invoke(["add", "test.ipynb", "attrs"])
+    invoke(["lock", "test.ipynb"])
+    assert jupytext.read(tmp_path / "test.ipynb").metadata.get("uv.lock") == snapshot("""\
+version = 1
+requires-python = ">=3.13"
+
+[options]
+exclude-newer = "2023-02-01T02:00:00Z"
+
+[manifest]
+requirements = [{ name = "attrs" }]
+
+[[package]]
+name = "attrs"
+version = "22.2.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/21/31/3f468da74c7de4fcf9b25591e682856389b3400b4b62f201e65f15ea3e07/attrs-22.2.0.tar.gz", hash = "sha256:c9227bfc2f01993c03f68db37d1d15c9690188323c067c641f1a35ca58185f99", size = 215900 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/fb/6e/6f83bf616d2becdf333a1640f1d463fef3150e2e926b7010cb0f81c95e88/attrs-22.2.0-py3-none-any.whl", hash = "sha256:29e95c7f6778868dbd49170f98f8818f78f3dc5e0e37c0b1f474e3561b240836", size = 60018 },
+]
+""")
+
+    result = invoke(["lock", "test.ipynb", "--clear"])
+    assert result.exit_code == 0
+    assert result.stdout == snapshot("Cleared lockfile `test.ipynb`\n")
+    assert jupytext.read(tmp_path / "test.ipynb").metadata.get("uv.lock") is None