fix(postcss-colormin): prevent interpreting all numbers as hex colors.

[ludofischer]

The issue is that the colord parser is so lenient it accepts single numbers
as hex colors.

Fix #1113, fix #1115

[ludofischer]

@omgovich do you agree with this solution? I wonder if the colord parser is not a bit too lenient. The interesting part is that the cssnano code never checks if color can be at that position, I guess because it is a bit complicated with all the shorthand declarations, so it relies on the color library failing to parse to decide whether to continue or not. Because colord accepts more values than color, cssnano ends up transforming any number with three digits.

[michaelfaith]

Thanks for the quick turnaround on this.

[omgovich]

Hey guys. Sad to see these issues.

Colord was created to help people to type a color values (for example, in color picker fields) and fix possible mistakes there. It produces valid CSS colors, but parses even broken ones. I've never aimed to handle any other input except possible color value before.

The current workaround is good enought I guess.
I'll try to find a more elegant solution for cssnano soon. Maybe implement some strict option to make the parser follow CSS specs.

[ludofischer]

We could use more readable integration test. The regression was visible in the generated output, and I even looked at it, but because the result is a single minified string, it is very easy to miss details. Maybe we should also run one plugin at a time on the sample CSS.

[codecov-commenter]

Codecov Report

Merging #1118 (9684747) into master (8a31ca3) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 9684747 differs from pull request most recent head 59d545b. Consider uploading reports for the commit 59d545b to get more accurate results

@@           Coverage Diff           @@
##           master    #1118   +/-   ##
=======================================
  Coverage   96.37%   96.37%           
=======================================
  Files         115      115           
  Lines        3582     3585    +3     
  Branches     1054     1056    +2     
=======================================
+ Hits         3452     3455    +3     
  Misses        121      121           
  Partials        9        9           

Impacted Files	Coverage Δ
packages/postcss-colormin/src/colours.js	100.00% <100.00%> (ø)

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[omgovich]

Already working on strict mode implementation for Colord.
Hope I'll release an update tomorrow and we'll be able to get rid of the workarounds and hacks.

[alexander-akait]

@ludofischer Do you think we should merge this and do fast release or better to migrate on v2 in other PR?

[ludofischer]

I think we should copy the tests from this in the other PR and release the other because this one is not that well tested either, so it's better to concentrate our attention on one PR

[michaelfaith]

Just to get a sense for timing, any thoughts when this might make it into a release? Just trying to guage whether or not i should use a workaround or wait for the fix.

[omgovich]

Colord v2 is released and PR that fixes everything is ready to merge #1122

[ludofischer]

Superseded by #1122

cssnano 5.0.4 with fixed color parsing is out, please give it a try.