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microsoft / vscode-markdown-languageservice

The language service that powers VS Code's Markdown support, extracted so that it can be reused by other editors and tools
MIT License
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Markdown footnote validation #100

Open mail2nnv opened 1 year ago

mail2nnv commented 1 year ago

Does this issue occur when all extensions are disabled?: Yes/No Yes

Steps to Reproduce:

  1. Create new markdown file
  2. Type a text: 
    text[^1]
  3. See problems: (×) No link definition found: '^1' (link.no-such-reference) [Ln 1, Col 6] 2022-11-22 14_23_58-test md - 555 - Visual Studio Code
GeorgyKwe commented 1 year ago

Try separating footnotes and citations by one line.

mail2nnv commented 1 year ago

Try separating footnotes and citations by one line.

Nothing changed. 2022-11-24 11_34_58-test md - 555 - Visual Studio Code

benblank commented 1 year ago

I'm sure this needs a more thorough look from someone familiar with the parser, but a quick check suggests that this behavior is the result of a conflict between how reference links are parsed and how link definitions are parsed.

Specifically, link definitions are explicitly not recognized if the reference name starts with a caret. (Note the (?!\^).)

https://github.com/microsoft/vscode-markdown-languageservice/blob/984eeb799db77906dd14115837abba2534890369/src/languageFeatures/documentLinks.ts#L323

Conversely, reference links aren't subject to that exclusion. (Called out here as the "link def".)

https://github.com/microsoft/vscode-markdown-languageservice/blob/984eeb799db77906dd14115837abba2534890369/src/languageFeatures/documentLinks.ts#L295-L313

As a result, footnotes appear to be interpreted as [shorthand]-style reference links which simply happen to start with a caret. But because the matching footnote definition isn't recognized as a link definition, the language service sees this as a link without a definition.

By my read, a fix for this could be as simple as removing (?!\^) from definitionPattern. Unless there's something else in the way, that should allow the parser to find the link definition. It'll still think the footnote is a link, though, and I don't know whether that could cause other issues.

villeodell commented 1 year ago

Just for additional context, even though most people's use case for this is footnotes, the following minimal example is parsed fine by commonmark.js (see here)

[^1]

[^1]: /url

However, vscode complains with

No link definition found: '^1'(link.no-such-reference)

hellt commented 2 months ago

footnotes are often used in rich documentation sites powered by mkdocs and the likes. Would be great to see this fixed

a few examples with footnotes that are not captured as a link in the current vscode markdown lsp:

[`Makefile`][makefile][^1]

`make`[^4]

[`text`](url)[^5]