feat: added new rule table-column-count #392
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| > This rule relies on the `table` AST node, typically available when using a GFM-compatible parser (e.g., `language: "markdown/gfm"`). | ||
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| This rule is triggered if a data row in a GFM table contains more cells than the header row. It does not flag rows with fewer cells than the header. |
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"It does not flag rows with fewer cells than the header."
Can I ask why this rule doesn’t report rows with fewer cells than the header? Is there a specific constraint?
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We chose to report tables with extra cells because, in Markdown, having more cells than headers leads to data loss, those extra cells are ignored when rendering the table. On the other hand, if a row has fewer cells, the table still renders correctly, and no data is lost.
Reporting rows with fewer cells felt more like a style concern rather than a functional issue, which is why I decided not to flag those.
Examples:
Valid (fewer cells, no data loss):
Input
| Header | Header | Header |
|--------|--------|--------|
| Cell | Cell | |
Output
| Header | Header | Header |
|---|---|---|
| Cell | Cell |
Invalid (extra cell, data is lost):
Input
| Head1 | Head2 |
|-------|-------|
| R1C1 | R1C2 | R1C3 |
Output
| Head1 | Head2 |
|---|---|
| R1C1 | R1C2 |
As shown, the actual problem arises when there are more cells than expected.
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Reference: #392 (comment)
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Can you add that explanation into the docs?
Prerequisites checklist
What is the purpose of this pull request?
This PR adds a new rule
table-column-countto disallow data rows in a GitHub Flavored Markdown table from having more cells than the header rowWhat changes did you make? (Give an overview)
Added the
table-column-countrule, along with documentation and tests.Related Issues
fixes #389
Is there anything you'd like reviewers to focus on?