Restore usage of flake8 and add to CI (#316)

* Restore flake8 configuration

* Fix f-strings missing placeholders

* Fix undefined local with import star

* Fix end of file should have one empty line

* Fix trailing whitespace

* Add pre-commit hooks

* Add lint step to CI

* Add pre-commit and hatch to dev dependencies

* Add linting contributing instructions

* Fix CI failure for old actions/cache version

* Ignore duplicate files in wheel

.babelrc

@@ -1,3 +1,3 @@
-{ 
+{
   "presets": ["es2015"],
 }

.bowerrc

@@ -1,3 +1,3 @@
 {
   "directory": "nbclassic/static/components"
-}
+}

.flake8

@@ -0,0 +1,10 @@
+[flake8]
+ignore = E, C, W, F401, F403, F811, F841, E402, I100, I101, D400
+builtins = c, get_config
+exclude =
+    .cache,
+    .github,
+    docs,
+    .venv,
+    dist,
+    build

.github/ISSUE_TEMPLATE/bug_report.md

@@ -69,4 +69,4 @@ Paste the output from your command line running `jupyter nbclassic` here, use `-
 Paste the output from your browser Javascript console here, if applicable.
 
 </pre>
-</details>
+</details>

.github/ISSUE_TEMPLATE/config.yml

@@ -2,4 +2,4 @@ blank_issues_enabled: false
 contact_links:
   - name: Is this a common issue? See our Docs.
     url: https://nbclassic.readthedocs.io/en/latest/troubleshooting.html#what-to-do-when-things-go-wrong
-    about: Before opening an issue, make sure your issue hasn't already been addressed in the documentation.
+    about: Before opening an issue, make sure your issue hasn't already been addressed in the documentation.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -36,4 +36,4 @@ Finally, please answer the following questions for yourself before submitting an
 <!-- Add any other context or screenshots about the feature request here. You can also include links to examples of other programs that have something similar to your request. For example:
 
 * Another project [...] solved this by [...]
--->
+-->

.github/workflows/check-release.yml

@@ -48,7 +48,7 @@ jobs:
           pip install -e .
       - name: Check Release
         if: ${{ matrix.group == 'check_release' }}
-        uses: jupyter-server/jupyter_releaser/.github/actions/check-release@v1
+        uses: jupyter-server/jupyter_releaser/.github/actions/check-release@v2
         with:
           version_spec: 100.100.100
           token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/pythonpackage.yml

@@ -7,6 +7,17 @@ on:
   pull_request:
 
 jobs:
+  lint:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/[email protected]
+        with:
+          python-version: '3.13'
+      - name: Lint with Pre-commit
+        uses: pre-commit/[email protected]
   build:
     runs-on: ${{ matrix.os }}
     strategy:

.pre-commit-config.yaml

@@ -0,0 +1,12 @@
+repos:
+-   repo: https://github.com/pycqa/flake8
+    rev: 'e43806be3607110919eff72939fda031776e885a'  # frozen: 7.1.1
+    hooks:
+    -   id: flake8
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: cef0300fd0fc4d2a87a85fa2093c6b283ea36f4b  # frozen: v5.0.0
+    hooks:
+        -   id: check-yaml
+        -   id: check-toml
+        -   id: end-of-file-fixer
+        -   id: trailing-whitespace

CONTRIBUTING.rst

@@ -84,6 +84,33 @@ running other instances of Jupyter NbClassic. You can try the following steps:
    a port that is neither the default nor in use, then it should be fine.
 5. Verify the installation with the steps in the previous section.
 
+Code Formatting and Linting
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+All source code is linted using `Flake8 <https://github.com/PyCQA/flake8>`_. When
+code is modified and committed, staged files are automatically checked for PEP 8
+compliance using pre-commit git hooks (with help from `pre-commit
+<https://github.com/pre-commit/pre-commit>`_). Using a linter like `flake8` helps
+maintain consistent code style and catches potential errors during pull request
+reviews, streamlining the review process. Other checks are also run to look for
+proper new lines at the end of files and to remove unnecessary whitespace.
+
+To install `pre-commit`, run::
+
+    pip install -e ".[dev]"
+    pre-commit install
+
+You can manually trigger the pre-commit hook at any time with::
+
+    pre-commit run
+
+This will check your code against the pre-commit checks and report any style
+violations or potential issues.
+
+If you committed files before setting up the pre-commit hook with
+`pre-commit install`, you can check all files using
+`pre-commit run --all-files`. You will need to fix any reported issues and commit
+the changes yourself afterward.
 
 Rebuilding JavaScript and CSS
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -137,9 +164,9 @@ To run the Python tests, use::
 For the end to end Pytest-Playwright tests you will need to install the browser binaries using::
 
     playwright install
-    
+
 Then you can run the end to end tests using::
-    
+
     pytest -sv nbclassic/tests/end_to_end
 
 If you want coverage statistics as well, you can run::

RELEASE.md

@@ -16,6 +16,6 @@ git clean -dffx
 python -m build
 tbump <new version number>
 pip install twine
-twine check dist/* 
+twine check dist/*
 twine upload dist/*
 ```

docs-translations/hi-IN/README.md

@@ -3,7 +3,7 @@
 [![Google Group](https://img.shields.io/badge/-Google%20Group-lightgrey.svg)](https://groups.google.com/forum/#!forum/jupyter)
 [![Build Status](https://travis-ci.org/jupyter/notebook.svg?branch=master)](https://travis-ci.org/jupyter/notebook)
 [![Documentation Status](https://readthedocs.org/projects/jupyter-notebook/badge/?version=latest)](https://jupyter-notebook.readthedocs.io/en/stable/?badge=latest)
-                
+
 
 
 Jupyter नोटबुक इंटरैक्टिव के लिए एक वेब-आधारित नोटबुक वातावरण है
@@ -74,4 +74,4 @@ IPython कोडबेस का बिग स्प्लिट ™। IPython
 - [Korean Version of Installation](https://github.com/ChungJooHo/Jupyter_Kor_doc/)
 - [Documentation for Project Jupyter](https://jupyter.readthedocs.io/en/latest/index.html )
 - [Issues](https://github.com/jupyter/nbclassic/issues)
-- [Technical support - Jupyter Google Group](https://groups.google.com/forum/#!forum/jupyter) 
+- [Technical support - Jupyter Google Group](https://groups.google.com/forum/#!forum/jupyter)

docs-translations/ja-JP/README.md

@@ -3,7 +3,7 @@
 [![Google Group](https://img.shields.io/badge/-Google%20Group-lightgrey.svg)](https://groups.google.com/forum/#!forum/jupyter)
 [![Build Status](https://travis-ci.org/jupyter/notebook.svg?branch=master)](https://travis-ci.org/jupyter/notebook)
 [![Documentation Status](https://readthedocs.org/projects/jupyter-notebook/badge/?version=latest)](https://jupyter-notebook.readthedocs.io/en/stable/?badge=latest)
-                
+
 英語版のリンク : [[English Version](http://github.com/jupyter/nbclassic/)]
 
 Jupyter Notebookは、インタラクティブなWebベースのノートブック形式の環境です。

docs-translations/ko-KR/HowtoRun.md

@@ -1,6 +1,6 @@
 # Notebook 실행하기
 
- ## 첫 걸음 
+ ## 첫 걸음
   1. 다음 명령어를 통해 Notebook 서버를 시작하세요 :
 
 	$ jupyter notebook
@@ -9,7 +9,7 @@
 
 
 # Notebook 서버 시작하기
- 
+
   Notebook을 컴퓨터에 설치하였으면 Notebook 서버를 시작할 수 있습니다. 다음 명령어를 이용하여 Notebook서버를 시작할 수 있습니다.
 
 	$ jupyter notebook
@@ -19,12 +19,12 @@
 	$ jupyter notebook
 	$ [I 08:58:24.417 NotebookApp] Serving notebooks from local directory: /Users/catherline
 	$ [I 08:58:24.417 NotebookApp] 0 active kernels
-	$ [I 08:58:24.417 NotebookApp] The Jupyter Notebook is running at: http://localhost:8888/ 
+	$ [I 08:58:24.417 NotebookApp] The Jupyter Notebook is running at: http://localhost:8888/
 	$ [I 08:58:24.417 NotebookApp] Use Control-C to stop this server and shut down all kernels
 
  기본 브라우저를 통해 이 주소가 열립니다.
 
- Notebook이 브라우저에 열리면, Notebook의 목록을 보여주는 Notebook Dashboard를 볼 수 있습니다. 대체로 가장 상위의 디렉토리를 열어줄 것입니다. 
+ Notebook이 브라우저에 열리면, Notebook의 목록을 보여주는 Notebook Dashboard를 볼 수 있습니다. 대체로 가장 상위의 디렉토리를 열어줄 것입니다.
 
  **Notebook Dashboard**
 
@@ -33,9 +33,9 @@
 # Notebook 서버의 명령어 소개
 
  ## 커스텀 IP 나 포트를 이용하여 시작하려면 어떻게 해야할까?
-  
+
  기본값으로, Notebook 서버는 포트 8888로 시작됩니다. 만약 포트8888이 사용할 수 없다면, Notebook 서버는 다른 가능한 포트를 찾습니다. 또한 임의로 포트를 설정해주는 것도 가능합니다. 예를 들어 포트 9999로 실행하면 :
- 
+
 	$ jupyter notebook --port 9999
 
 
@@ -45,13 +45,9 @@
 
 	$ jupyter notebook --no-browser
 
- 
+
  ## Notebook 서버 옵션 도움말 보기
 
  Notebook 서버는 --help 옵션을 통해 도움말 메시지를 제공합니다 :
 
 	$ jupyter notebook --help
-
-
-
-

docs-translations/ko-KR/Installation.md

@@ -10,20 +10,20 @@ Python과 Jupyter를 설치할 때 Anaconda를 이용하는 것을 추천합니
 
 새로운 이용자들은 Anaconda를 설치하는 것을 강력하게 추천합니다. Anaconda는 Python과 Jupyter를 쉽게 설치하게 해주고, 과학적인 계산과 데이터를 위한 자주 사용되는 패키지들의 설치에도 유용합니다.
 
-설치 순서 : 
-   
+설치 순서 :
+
    1. Anaconda를 다운받으세요. Anaconda의 가장 최신의 Python 3버전을 다운 받는 것을 추천합니다.
    2. 다운 받은 Anaconda 의 다운로드 페이지에 있는 설명을 읽고 설치해주세요.
    3. 축하합니다. Jupyter Notebook 을 설치하셨습니다. Jupyter Notebook을 실행하려면 :
 
 	$ jupyter notebook
 
 ## 숙련된 Python 이용자 : pip을 통해 설치하기
- 
+
  Python 이용자라면, Anaconda 대신에 Python의 패키지 매니저 pip을 이용하여 설치하세요.
 
  첫째로, 가장 최신의 pip인지를 확인하세요; 구 버전은 독립성에 문제가 있을 수 있습니다.
-   
+
     $ pip install --upgrade pip
 
  이제 다음을 이용하여 Jupyter Notebook를 설치하세요 :

docs-translations/ko-KR/README.md

@@ -3,7 +3,7 @@
 [![Google Group](https://img.shields.io/badge/-Google%20Group-lightgrey.svg)](https://groups.google.com/forum/#!forum/jupyter)
 [![Build Status](https://travis-ci.org/jupyter/notebook.svg?branch=master)](https://travis-ci.org/jupyter/notebook)
 [![Documentation Status](https://readthedocs.org/projects/jupyter-notebook/badge/?version=latest)](http://jupyter-notebook.readthedocs.io/en/stable/?badge=stable)
-                
+
 English 버전 링크 : [[English Version](http://github.com/jupyter/nbclassic/)]
 
 Jupyter notebook 은 상호 교환을 위한 웹 기반 환경입니다.
@@ -25,7 +25,7 @@ You can find the installation documentation for the
 조금 더 심화된 Jupyter notebook의 사용은 다음 주소에서 볼 수 있습니다.
 [here](https://jupyter-notebook.readthedocs.io/en/stable/).
 
-설치를 위해서는 
+설치를 위해서는
 [pip installed](https://pip.readthedocs.io/en/stable/installing/) 가 있는지 확인한 후 다음을 실행해주세요:
 
     $ pip install notebook

docs-translations/ko-KR/UIComponents.md

@@ -31,8 +31,3 @@ jupyter notebook 명령어를 실행하면 가장 먼저  Notebook Dashboard가
 이제 Notebook Dashboard 안의 Notebook 파일이 아닌 표시된 파일을 선택하여 열어야한다고 한다면, 파일은 파일 편집기로 열립니다.
 
 ![File Editor example](resources/file_editor.GIF "File Editor")
-
-
-
-
-

docs-translations/zh-CN/README.md

@@ -3,7 +3,7 @@
 [![Google Group](https://img.shields.io/badge/-Google%20Group-lightgrey.svg)](https://groups.google.com/forum/#!forum/jupyter)
 [![Build Status](https://travis-ci.org/jupyter/notebook.svg?branch=master)](https://travis-ci.org/jupyter/notebook)
 [![Documentation Status](https://readthedocs.org/projects/jupyter-notebook/badge/?version=latest)](https://jupyter-notebook.readthedocs.io/en/stable/?badge=latest)
-                
+
 
 
 Jupyter Notebook是用于交互的基于Web的笔记本环境
@@ -74,4 +74,4 @@ IPython代码库的Big Split™。 IPython 3是最后一个主要的整体
 - [Korean Version of Installation](https://github.com/ChungJooHo/Jupyter_Kor_doc/)
 - [Documentation for Project Jupyter](https://jupyter.readthedocs.io/en/latest/index.html )
 - [Issues](https://github.com/jupyter/nbclassic/issues)
-- [Technical support - Jupyter Google Group](https://groups.google.com/forum/#!forum/jupyter) 
+- [Technical support - Jupyter Google Group](https://groups.google.com/forum/#!forum/jupyter)

docs/Makefile

@@ -176,7 +176,7 @@ linkcheck:
 	@echo
 	@echo "Link check complete; look for any errors in the above output " \
 	      "or in $(BUILDDIR)/linkcheck/output.txt."
-		  
+
 spelling:
 	$(SPHINXBUILD) -b spelling $(ALLSPHINXOPTS) $(BUILDDIR)/spelling
 	@echo "Spell check complete; look for any errors in the above output " \

docs/autogen_config.py

@@ -11,7 +11,7 @@
 ====================================
 
 The notebook server can be run with a variety of command line arguments.
-A list of available options can be found below in the :ref:`options section 
+A list of available options can be found below in the :ref:`options section
 <options>`.
 
 Defaults for these options can also be set by creating a file named
@@ -29,7 +29,7 @@
 Options
 -------
 
-This list of options can be generated by running the following and hitting 
+This list of options can be generated by running the following and hitting
 enter::
 
   $ jupyter notebook --help

docs/jsdoc_config.json

@@ -2,7 +2,7 @@
     "markdown": {
         "parser": "gfm"
     },
-    "plugins": [ 
+    "plugins": [
         "plugins/markdown" ,
         "jsdoc_plugin.js"
     ],

docs/jsdoc_plugin.js

@@ -9,4 +9,4 @@ exports.handlers = {
             }
         }
     }
-};
+};

docs/shimming.md

@@ -66,4 +66,3 @@ Here's a snapshot of how JupyterApp's are initialized. The order of operations w
 ```
 
 ## Where do we add the steps above?
-

docs/source/_templates/sidebar-nav-bs-index.html

@@ -7,7 +7,7 @@
       font-weight: bold;
     }
   </style>
-  
+
   <nav class="bd-links" id="bd-docs-nav" aria-label="{{ _('Documentation Contents') }}">
     <div class="bd-toc-item navbar-nav">
       <!-- Specify a startdepth of 0 instead of default of 1 -->
@@ -21,4 +21,4 @@
         titles_only=True
       ) }}
     </div>
-  </nav>
+  </nav>

docs/source/config_docs.rst

@@ -12,4 +12,4 @@ Configuration
    security
    frontend_config
    examples/Notebook/Distributing Jupyter Extensions as Python Packages
-   extending/index.rst
+   extending/index.rst

docs/source/config_overview.rst

@@ -49,7 +49,7 @@ front-end NbClassic client (i.e. the familiar notebook interface).
             $ jupyter nbclassic --generate-config
 
       :ref:`Command line arguments for configuration <config>` settings are documented in the configuration file and the user documentation.
-      
+
   - Review the section: :ref:`Running a Notebook server <working_remotely>`
   - Related: `Configuring a language kernel <https://ipython.readthedocs.io/en/latest/install/kernel_install.html>`_
     to run in the Notebook server enables your server to run other languages, like R or Julia.

docs/source/examples/utils/list_pyfiles.ipy

@@ -3,4 +3,4 @@
 from IPython.display import FileLink, display
 files =!ls *.py
 for f in files:
-    display(FileLink(f))
+    display(FileLink(f))

docs/source/examples/utils/list_subdirs.ipy

@@ -4,4 +4,4 @@ from IPython.display import FileLinks, display
 dirs =!ls -d */
 for d in dirs:
     if d != '__pycache__/':
-        display(FileLinks(d))
+        display(FileLinks(d))