mergeLonghand is NOT SAFE! here is a case

[fjc0k]

raw css (generated by stylus mixin):

border: 0 solid rgba(0, 0, 0, 0.2);
border-top-width: 1px;
border-right-width: 1px;
border-bottom-width: 1px;
border-left-width: 1px;

minified css with mergeLonghand = true:

border: 0 solid rgba(0, 0, 0, 0.2);
border: 1px;

[alexander-akait]

@fjc0k what version cssnano you use?

[fjc0k]

@evilebottnawi 3.10.0

[alexander-akait]

@fjc0k can you try latest version rc?

[andyjansson]

npm i cssnano@next

[alexander-akait]

@fjc0k btw, what wrong with merge?

[prettyv]

I think what @fjc0k means is that the merge result should be

border: 0 solid rgba(0, 0, 0, 0.2);
border-width: 1px;

As is the merge result overwrites the whole border definition and loses width and color.

[fjc0k]

@evilebottnawi sorry, now i can’t test it. The worng is as @prettyv said.

[alexander-akait]

@fjc0k what result expected?

[fjc0k]

@evilebottnawi border: 0 solid rgba(0, 0, 0, 0.2); border-width: 1px;

_{Sent with GitHawk}

[An-Tu]

@fjc0k Are you sure that

border: 0 solid rgba(0, 0, 0, 0.2);
border-top-width: 1px;
border-right-width: 1px;
border-bottom-width: 1px;
border-left-width: 1px;

must be

border: 0 solid rgba(0, 0, 0, 0.2);
border-width: 1px;

?

Because I tested it locally, and i got this

border: 1px solid rgba(0, 0, 0, 0.2);

[fjc0k]

@An-Tu Oh, I think

border: 0 solid rgba(0, 0, 0, 0.2);
border-width: 1px;

is equal to

border: 1px solid rgba(0, 0, 0, 0.2);

What I want to say is that the result is wrong, not the form.

[sairus2k]

Already fixed in 4.0.0-rc.0. I think this issue might be closed.