[Bug]: invalid border shorthand with custom properties

[stefanprobst]

Describe the bug

the following:

h1 {
  --width: 8px 2px;
  border-width: var(--width);
  border-style: solid;
  border-color: hotpink;
}

results in (default preset):

h1{--width:8px 2px;border:var(--width) solid hotpink}

which is invalid.

Expected behaviour

when a custom property is encountered, don't collapse border properties into shorthand.

Steps to reproduce

1. paste the above snippet in the cssnano playground
2. click minimize

Version

whatever is currently on the cssnano playground, 5.1.0 probably

Preset

default

Environment

System:
    OS: Linux 5.13 KDE neon 5.24
    CPU: (4) x64 Intel(R) Core(TM) i5-6400T CPU @ 2.20GHz
    Memory: 19.96 GB / 31.30 GB
    Container: Yes
    Shell: 5.0.17 - /bin/bash

Package details

=> Found "postcss@8.4.5"

Additional context

No response

[stefanprobst]

the "lite" preset seems to handle this correctly

[ludofischer]

Duplicate of #675

the "lite" preset seems to handle this correctly

The lite preset disables declaration merging completely. You can also disable this optimisation in the default preset.