[ShawnNotFound]

Link to issue

Closes #5867

Description of change

The color validator now accepts the CSS color syntax that plotly.js parses: signed and exponent numbers, angle units other than deg, the none keyword, any color() color space, and transparent. Before, values like lab(50% -40 59.5) or color(srgb 1 0 0) raised a ValueError even though plotly.js renders them.

Demo

import plotly.graph_objects as go

go.Scatter(marker_color="lab(50% -40 59.5)")
# before: ValueError: Invalid value of type 'builtins.str' received for the 'color' property of scatter.marker
# after: accepted

Testing strategy

Added valid and invalid cases to test_color_validator.py. I checked each of them against culori, the parser plotly.js uses, so the validator accepts and rejects the same strings.

Additional information (optional)

The old code removed spaces before matching so the regex didn't have to handle them. The new regex handles whitespace itself, so that step is gone. Strings that don't form a valid color function, like rgb(255, 0) or rgb(1-2 3 4), are still rejected.

Guidelines

• I have reviewed the pull request guidelines and the Code of Conduct and confirm that this PR follows them.
• I have added an entry to the changelog if needed (not required for documentation PRs).

[chrikrah]

@ShawnNotFound blocking: the number pattern in _re_css_value can split a digit run anywhere, so an unclosed rgb( backtracks quadratically. One token fixes it:

-        r"(?:[+-]?(?:\d+\.?\d*|\.\d+)(?:e[+-]?\d+)?(?:%|deg|grad|rad|turn)?|none)"
+        r"(?:[+-]?(?:\d+(?:\.\d*)?|\.\d+)(?:e[+-]?\d+)?(?:%|deg|grad|rad|turn)?|none)"

# plotly 7.1.0 from PyPI, _plotly_utils/basevalidators.py overlaid from each ref, Python 3.12
# ColorValidator.perform_validate_coerce, seconds
input                       base 84498cc   head 527cd14   head + fix
"rgb(" + "1"*5000           < 0.05         3.03           < 0.05
"rgb(" + "1"*20000          < 0.05         41.96          < 0.05
"rgb(1 1 " + "1"*20000+"x"  < 0.05         45.95          < 0.05

$ python -m pytest test_color_validator.py -q -p no:cacheprovider
head 145 passed | basevalidators.py at base: 24 failed, 121 passed | head + fix: 145 passed
# 731 spacing and case variants of rgb/hsl/hwb/lab/lch/oklab/oklch and color(): head and head + fix accept the same set

Can you swap that line in? Nothing else blocks.

[ShawnNotFound]

Thanks, I have swapped that line.

[chrikrah]

@ShawnNotFound unclosed rgb( fails in milliseconds. Nothing here blocks a merge from my side.

# fd6f3ac exported with git archive, plotly 7.1.0 from PyPI with basevalidators.py overlaid; Python 3.12
$ python t.py     # perform_validate_coerce on "rgb(" + 20000 ones, seconds
0.002
$ python -m pytest tests/test_plotly_utils/validators/test_color_validator.py -q -p no:cacheprovider
145 passed in 0.28s
# basevalidators.py from main 3c1aeba, tests kept
24 failed, 121 passed in 0.90s

# _plotly_utils from git archive at each ref; Python 3.12.14
$ python -I probe.py <ref>     # ColorValidator("color", "scatter.marker").perform_validate_coerce
== 3c1aeba
'light blue' -> 'light blue'
'# ff0000' -> '# ff0000'
'hsl(0, 100 %, 50%)' -> 'hsl(0, 100 %, 50%)'
'rgb (255,0,0)' -> 'rgb (255,0,0)'
== fd6f3ac
'light blue' -> None
'# ff0000' -> None
'hsl(0, 100 %, 50%)' -> None
'rgb (255,0,0)' -> 'rgb (255,0,0)'

non-blocking: 'light blue' and '# ff0000' now raise where main returned them. Invalid CSS, so a fix. CHANGELOG line?

[ShawnNotFound]

Thanks for checking. Added a CHANGELOG line for it. plotly.js's color parser rejects those strings too, so the validator now matches what plotly.js renders.