!important without whitespace considered invalid in some cases

[ArgonAlex]

Related to csstree/csstree/issues/155

Should we be using matchDeclaration() instead of matchProperty()?

const { validate } = require('csstree-validator');
console.log(validate('a { width: calc(100% - 10px)!important }'));

[
	SyntaxError [SyntaxMatchError]: Mismatch
		at matchSyntax (node_modules\css-tree\lib\lexer\Lexer.js:87:17)
		at Lexer.matchProperty (node_modules\css-tree\lib\lexer\Lexer.js:331:16)
		at validateDeclaration (node_modules\csstree-validator\lib\validate.js:103:45)
		at List.<anonymous> (node_modules\csstree-validator\lib\validate.js:120:32)
		at List.each (node_modules\css-tree\lib\common\List.js:158:12)
		at validateRule (node_modules\csstree-validator\lib\validate.js:118:29)
		at Object.enter (node_modules\csstree-validator\lib\validate.js:158:28)
		at Object.<anonymous> (node_modules\css-tree\lib\walker\create.js:11:16) {
	  message: 'Invalid value for `width` property',
	  rawMessage: 'Mismatch',
	  syntax: 'auto | <length> | <percentage> | min-content | max-content | fit-content( <length-percentage> )',
	  css: 'calc(100% - 10px)!important',
	  mismatchOffset: 17,
	  mismatchLength: 1,
	  offset: 28,
	  line: 1,
	  column: 29,
	  loc: { source: '<unknown>', start: [Object], end: [Object] },
	  property: 'width',
	  details: 'Mismatch\n' +
		'  syntax: auto | <length> | <percentage> | min-content | max-content | fit-content( <length-percentage> )\n' +
		'   value: calc(100% - 10px)!important\n' +
		'  -------------------------^'
	}
  ]

[lahmatiy]

Thank you for the report! Now I see the origin of the issue and able to reproduce it.
I found that this is a bug in CSSTree's parser when parseValue option is set to false (it set to false in csstree-validator to speed up parsing since it not needed for a detailed AST for values). In this case !important is included into a value but must not. I will address a fix for this ASAP. The status can be tracked in csstree/csstree#155 (original report about the problem). But this issue is also useful since the bug affects csstree-validator and will indicate when fix will come into csstree-validator.

[ArgonAlex]

Thanks!

[lahmatiy]

Fixed in 2.0.1.

@ArgonAlex Thank you for the report once again!