fix: warn on document-structure tags inside LWC template (#3681)#5835
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Berestly wants to merge 1 commit into
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fix: warn on document-structure tags inside LWC template (#3681)#5835Berestly wants to merge 1 commit into
Berestly wants to merge 1 commit into
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wjhsf
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Jul 13, 2026
| @@ -0,0 +1,6 @@ | |||
| <template> | |||
| <!doctype html> | |||
| <html></html> | |||
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Can you add some tags with props? Also, what happens if there's more than one of a kind, since these are usually unique per document? What happens if there's an unmatched opening tag, or an unmatched closing tag?
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Hi Team,
Fixes #3681
Details
When
<!doctype>,<html>,<head>, or<body>appear inside an LWC template,parse5collapses them into a text node. LWC'sparseTextNodere-reads the raw source (to avoid HTML entity decoding), which accidentally causes the literal tag markup to leak through and render as visible text on the screen.This PR updates
parseTextNodeto intercept these document-structure tags, strip them from the output so they don't render, and emit a specific warning diagnostic (LWC1214) per tag to notify the developer.Summary of Changes:
@lwc/errors: AddedDOCUMENT_STRUCTURE_TAG_NOT_ALLOWED_IN_TEMPLATE(Warning code1214) totemplate-transform.tsand bumped the next error code marker to1215inindex.ts.@lwc/template-compiler: Added matching regex rules inconstants.tsand wired them intoparseTextNodeinsideparser/index.ts.disallowed-document-structure-tags) verifying that the compiler cleanly strips out the invalid markup and emits four individualLWC1214warnings.Does this pull request introduce a breaking change?
🗿 No, it does not introduce a breaking change.
Does this pull request introduce an observable change?
✅ Yes, it does include an observable change.
Anticipated Observable Changes:
LWC1214compiler warning in the console if they include document-level tags inside an LWC template.<html>) will no longer render onto the viewport at runtime.GUS work item
W-18040860
Thanks!