fix: render true booleans as "true" in XML output

[gennaroprota]

The XML writer emitted true boolean members as <x>1</x> (and omitted the element when false). It now emits the xsd:boolean primary lexical form, <x>true</x>. The omit-when-false convention is preserved, so the golden XMLs change only in the body of already-present boolean elements. The RELAX NG schema is updated accordingly.

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Summary

Fixes a long-standing readability quirk in the XML output. The XML writer emitted true boolean members as <x>1</x> (and omitted the element when false). Reading such output meant the consumer had to know in advance that the member was actually a boolean — 1 looks indistinguishable from an integer.

The writer now emits the xsd:boolean primary lexical form: <x>true</x>. The omit-when-false convention is preserved, so the golden XML fixtures change only in the body of already-present boolean elements. The RELAX NG schema is updated to match.

Changes

• Source: One-line fix in src/lib/Gen/xml/XMLWriter.cpp — the boolean-serialization branch now writes "true" instead of "1".
• Golden tests: 207 XML fixtures across test-files/golden-tests/ updated to reflect the new <x>true</x> form. Intentional output corrections, not regenerations.
• Build: mrdocs.rnc updated so the schema accepts the new lexical form on boolean elements.
• Breaking changes: Downstream tooling that parses mrdocs XML output and matches boolean fields exactly against "1" will need to update to handle "true". The omit-when-false convention is unchanged, so handling for absent elements is unaffected.

Testing

• The 207 golden XML fixtures are themselves the regression coverage: any future regression that re-emits "1" for booleans (or omits an element when true) fails the golden tests.
• No CI workflow changes needed — the existing golden-test job runs test-files/golden-tests/ on every build, so the new expectations stay enforced going forward.

Documentation

The schema (mrdocs.rnc) is the canonical reference for the XML output format and is updated. No prose documentation describes the previous "1" encoding, so nothing else needs updating.

[github-actions]

✨ Highlights

• 🧪 Existing golden tests changed (behavior likely shifted)

🧾 Changes by Scope

Scope	Lines Δ%	Lines Δ	Lines +	Lines -	Files Δ	Files +	Files ~	Files ↔	Files -
🥇 Golden Tests	100%	4608	2304	2304	209	-	209	-	-
🛠️ Source	<1%	2	1	1	1	-	1	-	-
🏗️ Build	<1%	2	1	1	1	-	1	-	-
Total	100%	4612	2306	2306	211	-	211	-	-

Legend: Files + (added), Files ~ (modified), Files ↔ (renamed), Files - (removed)

🔝 Top Files

• test-files/golden-tests/symbols/variable/function-objects.xml (Golden Tests): 370 lines Δ (+185 / -185)
• test-files/golden-tests/symbols/record/class-template-specializations-1.xml (Golden Tests): 312 lines Δ (+156 / -156)
• test-files/golden-tests/config/inherit-base-members/copy.xml (Golden Tests): 204 lines Δ (+102 / -102)

Generated by 🚫 dangerJS against 2b9534e

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.12%. Comparing base (74bf1a3) to head (2b9534e).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1200   +/-   ##
========================================
  Coverage    82.12%   82.12%           
========================================
  Files           33       33           
  Lines         3149     3149           
  Branches       734      734           
========================================
  Hits          2586     2586           
  Misses         387      387           
  Partials       176      176           

Flag	Coverage Δ
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[cppalliance-bot]

An automated preview of the documentation is available at https://1200.mrdocs.prtest2.cppalliance.org/index.html

If more commits are pushed to the pull request, the docs will rebuild at the same URL.

2026-05-20 07:43:51 UTC

[alandefreitas]

The XML writer emitted true boolean members as 1 (and omitted the element when false). It now emits the xsd:boolean primary lexical form, true. The omit-when-false convention is preserved

I'm no XML expert, but that seems like a weird convention to make. If we omit when false, this is technically a flag. And flags don't have to say "true". I thought booleans were typically represented as attributes in XML.

[gennaroprota]

The XML writer emitted true boolean members as 1 (and omitted the element when false). It now emits the xsd:boolean primary lexical form, true. The omit-when-false convention is preserved

I'm no XML expert, but that seems like a weird convention to make. If we omit when false, this is technically a flag. And flags don't have to say "true".

I was going to point out the same. true is currently redundant.

I thought booleans were typically represented as attributes in XML.

Yes. For us, the form would be something like:

<function name="foo" is-const="true" is-variadic="false" ...>
  <param>...</param>
  ...
</function>

The MrDocs schema currently has almost no data attributes, so booleans-as-elements is at least consistent. I'd suggest switching to "empty element (e.g. <is-variadic/>) when true, nothing when false", as that avoids the enormous diff that would result from moving all booleans to attributes.