[release/stable] Resolve consecutive WithoutEndTag tag helpers as siblings - #84782
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[release/stable] Resolve consecutive WithoutEndTag tag helpers as siblings#84782github-actions[bot] wants to merge 2 commits into
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## Summary Consecutive tag helpers declared with `TagStructure.WithoutEndTag` and written without a self-closing slash (e.g. `<meta-description><meta-keywords><head-custom>`) only bind the **first** helper. The rest are emitted as literal, unprocessed markup. This is a regression from the deferred tag helper lowering work (dotnet/razor#12957), which moved tag helper resolution after IR lowering. It was reported downstream as [dotnet/aspnetcore#68193](https://github.com/dotnet/aspnetcore/issues/68193): a GrandNode app rendered a blank page (`Uncaught ReferenceError: Vue is not defined`) because the `<head>` script-registration tag helpers silently stopped running and the Vue bundle was never emitted. ## Root cause The HTML parser nests consecutive unclosed tags, so `<a><b><c>` parses as `a > b > c`. When `DefaultTagHelperResolutionPhase.ResolveElement` binds `a` as a `StartTagOnly` helper, it promotes `a`'s parser-nested body children to be **siblings** inserted *after* `a`. But the element walker `ResolveElements` iterates children in reverse, so it has already moved past that position and never resolves the promoted siblings. They remain `UnresolvedElementIntermediateNode`s and are later unwrapped to literal HTML. The `ConvertToPlainElement` path already re-resolves its promoted siblings; the direct `ResolveElement` `StartTagOnly` path was missing the equivalent step. ## Fix After promoting the `StartTagOnly` element's children to siblings, resolve them in place (in reverse, since resolving a promoted `StartTagOnly` sibling can itself insert further siblings). This mirrors the existing pattern in `ConvertToPlainElementAndResolve`. ## Testing Two new integration tests in `TagHelpersIntegrationTest`: - `ConsecutiveWithoutEndTagTagHelpers_AllBind` -- three consecutive `WithoutEndTag` helpers all bind. - `MixedNestedStartTagOnlyAndHtmlTagHelpers_AllResolveCorrectly` -- a tangled mix of a nestable helper, consecutive `WithoutEndTag` helpers, a normal helper, and real HTML (`<section>`, `<div>`); asserts every helper binds in document order and real markup is preserved. Both fail without the fix (only the first helper binds) and pass with it (net10.0 and net472). > Note: this regression is also present in the shipping .NET 10 GA Razor compiler, so a servicing backport is likely warranted. ###### Microsoft Reviewers: [Open in CodeFlow](https://microsoft.github.io/open-pr/?codeflow=https://github.com/dotnet/roslyn/pull/84771) --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: e4a482bf-ffc0-4a98-a673-863b5e84c6d8
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The backport squash kept release/stable's using block, dropping the Microsoft.AspNetCore.Razor.Language.Intermediate and Roslyn.Test.Utilities imports the tests need, which broke the build with CS0246 on TagHelper IR types and the WorkItem attribute. Add them back. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: e4a482bf-ffc0-4a98-a673-863b5e84c6d8
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Backport of #84771 to release/stable
/cc @chsienki
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Microsoft Reviewers: Open in CodeFlow