Extract rule: template-require-valid-alt-text

[NullVoxPopuli]

Split from #2371.

[NullVoxPopuli-ai-agent]

Review: template-require-valid-alt-text (PR #2614)

Comparison with ember-template-lint source

General correctness:

1. Error message differences (minor): Several messages have slightly different punctuation:

   • ETL: "All <img> tags must have an alt attribute" → ESLint: adds period at end
   • ETL: "The alt text must not be the same as the image source" → ESLint: adds period
   • ETL: "A number is not valid alt text" → ESLint: adds period
   • ETL: "The alt attribute should be empty if <img> has role of none or presentation" → ESLint: wraps in backticks and quotes differently
     These are cosmetic but will cause test failures if anyone is matching exact messages from the original.

2. imgRedundant reported on altAttr node, not node: In the ESLint version, the redundant words error reports on altAttr (the attribute node) instead of node (the element node). The original ETL always reports on the element node. This is actually a nice improvement for editor UX (highlights just the attribute), but it's a behavioral difference.

3. img role=presentation check order: The ESLint version checks altAttr && roleAttr first, then checks !altAttr. The original checks role+alt validation AFTER the main alt presence check. But in the ESLint version, if both altAttr and roleAttr exist and it's role=presentation with non-empty alt, it reports imgRolePresentation but does NOT return — it continues to also check for redundant words, numeric alt, etc. The original also does this (the role check is before the if (!hasAltAttribute) check and doesn't return). So both can report multiple errors for the same element, which matches.

4. hasAccessibleChild for <object>: The original ETL uses AstNodeInfo.hasChildren(node) which likely checks for any child nodes (including text nodes with content). The ESLint version's hasChildren() function filters text nodes by chars.trim().length > 0, which is equivalent.

5. Missing <object> title attribute behavior: The original checks roleValue directly against ['presentation', 'none'] — and roleValue could be a MustacheStatement node object if dynamic, in which case includes() would return false. The ESLint version uses getTextValue(roleAttr) which returns undefined for non-TextNode types, and 'presentation' || 'none'].includes(undefined) is false. This matches.

Scope analysis (gjs/gts):

Not applicable. This rule only checks HTML element tags (img, input, object, area) and their attributes. No helper/component name resolution is involved.

Tests: Comprehensive test coverage matching the original ETL test cases. Both gjs and hbs modes tested. Good.

Summary: Solid migration with good fidelity to the original. Minor message punctuation differences. No blocking issues.

🤖 Automated review comparing with ember-template-lint source