Large, Unnecessary Duplication of @supports Statements

[dwighthouse]

Bug description

When specifying a series of things that generate @supports statements as part of their compatibility, identical, adjacent @supports statements will be meaninglessly generated individually where they should be combined, at least in cases where they are adjacent. Additional analysis could probably support the combining of similar statements that are not adjacent.

I have encountered the behavior in my project. The behavior is easily viewable in the interactive playground as well.

Source CSS

:root {
  --color1: oklch(52% 0.21 270);
  --color2: oklch(45% 0.21 270);
}

Expected CSS

:root {
    --color1: rgb(62, 85, 223);
    --color2: rgb(46, 62, 199);
}

@supports (color: color(display-p3 0 0 0)) {
    :root {
        --color1: color(display-p3 0.26256 0.33170 0.84336);
        --color2: color(display-p3 0.19377 0.23995 0.75043);
    }
}

Actual CSS

:root {
    --color1: rgb(62, 85, 223);
    --color2: rgb(46, 62, 199);
}

@supports (color: color(display-p3 0 0 0)) {
    :root {
        --color1: color(display-p3 0.26256 0.33170 0.84336);
    }
}

@supports (color: color(display-p3 0 0 0)) {
    :root {
        --color2: color(display-p3 0.19377 0.23995 0.75043);
    }
}

Does it happen with npx @csstools/csstools-cli <plugin-name> minimal-example.css?

N/A

Debug output

I do not know how to do this. The debug explainer link leads to out-of-date documentation.

Extra config

No response

What plugin are you experiencing this issue on?

PostCSS Env Function

Plugin version

8.0.1

What OS are you experiencing this on?

macOS

Node Version

17.0.1

Validations

• Follow our Code of Conduct
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

Would you like to open a PR for this bug?

• I'm willing to open a PR

[dwighthouse]

Wow! Thanks for looking at this so quickly!

[romainmenke]

Always happy to help!

I forgot to post an update here after the release, luckily you spotted it :)