fix(compiler-dom): leave out boolean attributes with falsy constant values when stringifying

[lprnmns]

When a static subtree gets stringified, a constant binding on a boolean attribute is only left out if its source is exactly false (#6568), or if it is hidden with a number. Any other falsy constant is printed as the attribute's value:

<input :disabled="0">  <!-- stringified as <input disabled="0"> -->
<input :checked="!1">  <!-- stringified as <input checked="false"> -->

A boolean attribute is on whenever it is present, so these inputs end up disabled/checked. At runtime and in SSR (includeBooleanAttr), the same bindings leave the attribute out. So the result depends on whether the surrounding markup reaches the stringify thresholds. I found this by rendering random static templates with and without stringification in jsdom and comparing the DOM. For example, :disabled="0" on a <textarea> came out disabled only when stringified.

This applies the existing hidden check to every boolean attribute and every falsy constant (0, -0, !1, 1 > 2, ...), using includeBooleanAttr like the runtime does.

The new stringifyStatic.spec.ts cases fail without the change. vitest run for compiler-dom/core/sfc and server-renderer (1651 tests), tsc --noEmit, ESLint and Prettier pass.

Summary by CodeRabbit

• Bug Fixes
  • Static HTML output now correctly omits boolean attributes, including disabled, checked, and hidden, when their bound values are false.

[coderabbitai]

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ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: defaults
• Review profile: CHILL
• Plan: Advanced
• Run ID: 2bbd2a69-f26c-4c37-9405-4fda39659b47

📥 Commits

Reviewing files that changed from the base of the PR and between bf5f0dd and be13568.

📒 Files selected for processing: 2

• packages/compiler-dom/__tests__/transforms/stringifyStatic.spec.ts
• packages/compiler-dom/src/transforms/stringifyStatic.ts

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📝 Walkthrough

Static stringification now omits constant false values for boolean attributes and hidden. Tests cover disabled and checked with four falsy expressions.

Changes: Static stringification

Layer / File(s)	Summary
Omit false boolean attributes packages/compiler-dom/src/transforms/stringifyStatic.ts, packages/compiler-dom/__tests__/transforms/stringifyStatic.spec.ts	The omission check now covers boolean attributes and hidden when includeBooleanAttr returns false. Tests verify that four falsy expressions produce repeated <input> elements without disabled or checked.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~8 minutes

Change: Bug fix

Suggested reviewers: chirokas

Merge Risk: ⚪ Minimal · up to be135

Static rendering omits false boolean attributes while preserving empty-string and string-valued hidden attributes, consistent with runtime behavior. No merge-blocking risk is established.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: omitting boolean attributes when constant values are falsy during static stringification.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

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