TypeError: Cannot read property 'stringify' of undefined (8.3.0 -> 8.4.16)

[Lonli-Lokli]

I faced an issue with upgrading my Nx codebase (React+StyledComponents) to the latrst version. The change I noticed is that version goes up 8.3.0 -> 8.4.16
I do not have working small reproduction, if you think you will need it can you explain what sample will satisfy your needs (complexity)

My assumption here is that now this module cannot handle empty files or files without styled components

 $) stylelint "**/*.{ts,tsx}"

TypeError: Cannot read property 'stringify' of undefined
    at Function.stringify (D:\sources\rmboa\node_modules\postcss-syntax\stringify.js:8:38)
    at MapGenerator.generate (D:\sources\rmboa\node_modules\stylelint\node_modules\postcss\lib\map-generator.js:323:12)
    at LazyResult.stringify (D:\sources\rmboa\node_modules\stylelint\node_modules\postcss\lib\lazy-result.js:277:20)
    at LazyResult.runAsync (D:\sources\rmboa\node_modules\stylelint\node_modules\postcss\lib\lazy-result.js:443:17)
    at LazyResult.async (D:\sources\rmboa\node_modules\stylelint\node_modules\postcss\lib\lazy-result.js:221:30)
    at LazyResult.then (D:\sources\rmboa\node_modules\stylelint\node_modules\postcss\lib\lazy-result.js:206:17)

[ai]

Sorry, you need to open this issue in Stylelint.

If you will know what to change in PostCSS core open a new issue.

[AndreyYevtukhov]

@Lonli-Lokli

did you open that issue in https://github.com/stylelint/stylelint?
or maybe found a solution? :)

[Lonli-Lokli]

Unfortunately not for both cases. I think it's related to latest changes in postcss to lazy load, but everyone needs a clean simple reproduction without external libraries

[omjokine]

I have this same issue. Unfortunately I don't have very simple piece of code to reproduce this issue, but got the same stack trace as OP had.

This happened when updated postcss from 8.4.14 to 8.4.16. So I can reproduce it simply running npm update postcss and then running stylelint. So I guess it is regression in postcss, not in stylelint.

[tomof]

I faced the same problem. Fortunately, the repository is publicly available, so I will post the URL of the pull request by the Renovate bot that caused the problem. I hope this helps.

• Update dependency stylelint to ^14.16.0 kufu/smarthr-design-system#239
• Update postcss from 8.4.14 to 8.4.16.
  • https://github.com/kufu/smarthr-design-system/pull/239/files#diff-51e4f558fae534656963876761c95b83b6ef5da5103c4adef6768219ed76c2deR17820
• Error log
  • https://github.com/kufu/smarthr-design-system/runs/7832428358?check_suite_focus=true

[Lonli-Lokli]

@ai Can you please reiterate this issue? Do you still think it should be fixed in stylelint?

[AndreyYevtukhov]

we have solved it by adding

"overrides": {
    "postcss": "^8.4.16"
  }

in package.json

[Lonli-Lokli]

Unfortunately that's only workaround and also requires Node16

[ai]

Can you please reiterate this issue?

I will re-open this issue only if we will have explicit understandard what do we need to change in the core.

Before it, better to discuss it in Stylelint issue.

[Lonli-Lokli]

@ai Here is my findings.
postcss-syntax expecting to have document (aka root) to be Document
https://github.com/gucong3000/postcss-syntax/blob/master/stringify.js#L5-L7

Which does not happen with new version

postcss/lib/container.js

Lines 419 to 429 in bc5b964

	if (node.type === 'atrule') {
	Object.setPrototypeOf(node, AtRule.prototype)
	} else if (node.type === 'rule') {
	Object.setPrototypeOf(node, Rule.prototype)
	} else if (node.type === 'decl') {
	Object.setPrototypeOf(node, Declaration.prototype)
	} else if (node.type === 'comment') {
	Object.setPrototypeOf(node, Comment.prototype)
	} else if (node.type === 'root') {
	Object.setPrototypeOf(node, Root.prototype)
	}

While was happening with the old one

postcss/lib/container.js

Lines 415 to 423 in b7d1836

	if (node.type === 'atrule') {
	Object.setPrototypeOf(node, AtRule.prototype)
	} else if (node.type === 'rule') {
	Object.setPrototypeOf(node, Rule.prototype)
	} else if (node.type === 'decl') {
	Object.setPrototypeOf(node, Declaration.prototype)
	} else if (node.type === 'comment') {
	Object.setPrototypeOf(node, Comment.prototype)
	}

As a result stringifier goes into the https://github.com/gucong3000/postcss-syntax/blob/master/stringify.js#L8
source property does not exists and we are facing an issue.

[ai]

Seems like postcss-syntax is hack the AST.

We can’t just remove node.type === 'root' because it is fixed another bug.

Here are my suggestions:

1. Fix Stylelint and set .source.syntax.stringify to some custom analog of docStringify
2. Find a way to detect Document from postcss-syntax and avoid conversation. But I afraid it will break AST normalization fix.