From a64df28d5ce5788a124e7353c696241087defa22 Mon Sep 17 00:00:00 2001
From: Remco de Boer <29308176+redeboer@users.noreply.github.com>
Date: Mon, 8 Jul 2024 16:58:28 +0200
Subject: [PATCH] FEAT: remove tags from notebook cell if empty (#350)

* FIX: remove `slideshow` from config cell
---
 .pre-commit-hooks.yaml                 |  9 ++++++
 pyproject.toml                         |  1 +
 src/compwa_policy/remove_empty_tags.py | 45 ++++++++++++++++++++++++++
 src/compwa_policy/set_nb_cells.py      |  1 -
 4 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 src/compwa_policy/remove_empty_tags.py

diff --git a/.pre-commit-hooks.yaml b/.pre-commit-hooks.yaml
index 155abe1b..2e012046 100644
--- a/.pre-commit-hooks.yaml
+++ b/.pre-commit-hooks.yaml
@@ -19,6 +19,15 @@
   types:
     - jupyter
 
+- id: remove-empty-tags
+  name: Remove empty tags metadata field from Jupyter notebooks
+  description: >
+    Remove the tags metadata field from Jupyter notebooks if there are no tags
+  entry: remove-empty-tags
+  language: python
+  types:
+    - jupyter
+
 - id: set-nb-cells
   name: Add or update default cells in a Jupyter notebook
   description: >
diff --git a/pyproject.toml b/pyproject.toml
index 64d368fd..e3fb1fca 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -87,6 +87,7 @@ file = "README.md"
 check-dev-files = "compwa_policy.check_dev_files:main"
 colab-toc-visible = "compwa_policy.colab_toc_visible:main"
 fix-nbformat-version = "compwa_policy.fix_nbformat_version:main"
+remove-empty-tags = "compwa_policy.remove_empty_tags:main"
 self-check = "compwa_policy.self_check:main"
 set-nb-cells = "compwa_policy.set_nb_cells:main"
 
diff --git a/src/compwa_policy/remove_empty_tags.py b/src/compwa_policy/remove_empty_tags.py
new file mode 100644
index 00000000..0167cc7a
--- /dev/null
+++ b/src/compwa_policy/remove_empty_tags.py
@@ -0,0 +1,45 @@
+"""Remove tags metadata from notebook cells if they are empty."""
+
+from __future__ import annotations
+
+import argparse
+import sys
+from typing import Sequence
+
+import nbformat
+
+from compwa_policy.errors import PrecommitError
+from compwa_policy.utilities.executor import Executor
+from compwa_policy.utilities.notebook import load_notebook
+
+
+def main(argv: Sequence[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(__doc__)
+    parser.add_argument("filenames", nargs="*", help="Filenames to check.")
+    args = parser.parse_args(argv)
+
+    with Executor(raise_exception=False) as do:
+        for filename in args.filenames:
+            do(_remove_cells, filename)
+    return 1 if do.error_messages else 0
+
+
+def _remove_cells(filename: str) -> None:
+    notebook = load_notebook(filename)
+    updated = False
+    for cell in notebook["cells"]:
+        metadata = cell["metadata"]
+        tags = metadata.get("tags")
+        if tags is None:
+            continue
+        if not tags:
+            metadata.pop("tags")
+            updated = True
+    if updated:
+        nbformat.write(notebook, filename)
+        msg = f'Removed empty tags cell metadata from "{filename}"'
+        raise PrecommitError(msg)
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/src/compwa_policy/set_nb_cells.py b/src/compwa_policy/set_nb_cells.py
index a5119af4..9c4d4d43 100644
--- a/src/compwa_policy/set_nb_cells.py
+++ b/src/compwa_policy/set_nb_cells.py
@@ -41,7 +41,6 @@
     "hideOutput": True,
     "hidePrompt": True,
     "jupyter": {"source_hidden": True},
-    "slideshow": {"slide_type": "skip"},
     "tags": ["remove-cell"],
 }