Issues with Python escaping in test_traits.py

[andy-maier]

Description

The test module test_traits.py has two issues with Python escaping:

test_traits.py, lines 60 and 61:

        r'var(--my-color-\\1234)', # CSS variable escaped hex character
        'var(--my-color-\.)', # CSS variable with escaped characters

Line 60 probably has the issue that \\ in a raw string results in two \ characters. I don't think this is what is intended here. The comment suggests the intention is to specify an escaped hex character, which would be:

        r'var(--my-color-\x1234)', # CSS variable escaped hex character

Line 61 has the issue that \ in a non-raw string is interpreted as a Python escape, along with the following character .. This is obviously not a valid Python escape character, and Python issues a SyntaxWarning:

$ python
Python 3.12.7 (main, Oct  1 2024, 02:05:46) [Clang 15.0.0 (clang-1500.3.9.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> s = 'var(--my-color-\.)'
<stdin>:1: SyntaxWarning: invalid escape sequence '\.'

I don't think this is what is intended here, but I'm not sure what the solution would be. Maybe just specifying this as a raw string:

        r'var(--my-color-\.)', # CSS variable with escaped characters

Reproduce

For reproducing the SyntaxWarning, see above.

I found this when checking for missing dependencies using the 'pip-missing-reqs' command from the 'pip-check-reqs' package:

1. Create and activate a fresh Python virtual environment

mkvirtualenv ipy312 -p python3.12

2. Create a dependencies file:

cat >deps.txt << EOF
ipywidgets
pip-check-reqs
jsonschema
pytest
traitlets
ipython
comm
ipykernel
EOF

3. Install packages:

pip install -r deps.txt

4. Check for missing dependencies:

pip-missing-reqs $(python -c "import ipywidgets as m, os; dm=os.path.dirname(m.__file__); print(dm)") --requirements-file=deps.txt
...../site-packages/ipywidgets/widgets/tests/test_traits.py:61: SyntaxWarning: invalid escape sequence '\.'
  'var(--my-color-\.)', # CSS variable with escaped characters

Expected behavior

No SyntaxWarning

Context

• ipywidgets version: 8.1.5
• Operating System and version: macOS 14.7.2
• Browser and version: N/A

Troubleshoot Output

(ipywidgets312) maiera-mbp-3:ipywidgets maiera$ jupyter troubleshoot
$PATH:
	/Users/maiera/virtualenvs/ipywidgets312/bin
	/Users/maiera/local/bin
	/opt/homebrew/bin
	/opt/homebrew/sbin
	/usr/local/bin
	/System/Cryptexes/App/usr/bin
	/usr/bin
	/bin
	/usr/sbin
	/sbin
	/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin
	/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin
	/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin
sys.path:

/Users/maiera/virtualenvs/ipywidgets312/bin

/opt/homebrew/Cellar/python@3.12/3.12.7_1/Frameworks/Python.framework/Versions/3.12/lib/python312.zip

/opt/homebrew/Cellar/python@3.12/3.12.7_1/Frameworks/Python.framework/Versions/3.12/lib/python3.12

/opt/homebrew/Cellar/python@3.12/3.12.7_1/Frameworks/Python.framework/Versions/3.12/lib/python3.12/lib-dynload

/Users/maiera/virtualenvs/ipywidgets312/lib/python3.12/site-packages
sys.executable:

/Users/maiera/virtualenvs/ipywidgets312/bin/python
sys.version:

3.12.7 (main, Oct  1 2024, 02:05:46) [Clang 15.0.0 (clang-1500.3.9.4)]
platform.platform():

macOS-14.7.2-arm64-arm-64bit
which -a jupyter:

/Users/maiera/virtualenvs/ipywidgets312/bin/jupyter
pip list:

Package                   Version

------------------------- -----------

appnope                   0.1.4

asttokens                 3.0.0

attrs                     25.1.0

comm                      0.2.2

debugpy                   1.8.12

decorator                 5.1.1

executing                 2.2.0

iniconfig                 2.0.0

ipykernel                 6.29.5

ipython                   8.31.0

ipywidgets                8.1.5

jedi                      0.19.2

jsonschema                4.23.0

jsonschema-specifications 2024.10.1

jupyter_client            8.6.3

jupyter_core              5.7.2

jupyterlab_widgets        3.0.13

matplotlib-inline         0.1.7

nest-asyncio              1.6.0

packaging                 24.2

parso                     0.8.4

pexpect                   4.9.0

pip                       24.3.1

pip-check-reqs            2.5.3

platformdirs              4.3.6

pluggy                    1.5.0

prompt_toolkit            3.0.50

psutil                    6.1.1

ptyprocess                0.7.0

pure_eval                 0.2.3

Pygments                  2.19.1

pytest                    8.3.4

python-dateutil           2.9.0.post0

pyzmq                     26.2.0

referencing               0.36.2

rpds-py                   0.22.3

six                       1.17.0

stack-data                0.6.3

tornado                   6.4.2

traitlets                 5.14.3

typing_extensions         4.12.2

wcwidth                   0.2.13

widgetsnbextension        4.0.13

Command Line Output

N/A

Browser Output

N/A

If using JupyterLab

• JupyterLab version: N/A

Installed Labextensions

N/A