fix(gottext): name a translation whose tags differ from its message

gottext/CHANGELOG.md

@@ -5,6 +5,12 @@ versioning follows [Semantic Versioning](https://semver.org/). While at 0.x,
 minor releases may break. Releases are tagged `gottext/vX.Y.Z` and publish
 from CI.
 
+## [Unreleased]
+
+### Fixed
+
+- `mismatched` reads the tags a message carries, so a translation that adds, drops, renames or repeats one is named.
+
 ## [0.8.0] - 2026-11-02
 
 ### Changed

gottext/src/gates.ts

@@ -100,7 +100,7 @@ function bare(message: string): string[] {
 }
 
 /**
- * Returns whether two placeholder lists hold the same members.
+ * Returns whether two lists hold the same members.
  * @param left - The list on the left.
  * @param right - The list on the right.
  * @returns Whether both hold the same members.
@@ -122,6 +122,31 @@ function answersPlaceholders(form: string, message: string): boolean {
 	return alike(placeholders(form), placeholders(message)) && alike(bare(form), bare(message))
 }
 
+/** TAG is a tag as createInterpolateElement reads one, with the slashes that mark it closing or self closing. */
+const TAG = /<(\/)?(\w+)\s*(\/)?>/g
+
+/**
+ * Returns the tags a message carries, each whole and once per use, in a settled order.
+ * @param message - The message to read.
+ * @returns The tags, sorted.
+ */
+function tags(message: string): string[] {
+	return [...message.matchAll(TAG)].map((found) => `${found[1] ?? ''}${found[2]}${found[3] ?? ''}`).sort()
+}
+
+/**
+ * Returns whether a translated form answers its message with the tags that message carries.
+ * @param form - The translated form.
+ * @param message - The message the form answers.
+ * @returns Whether the form matches.
+ */
+function answersTags(form: string, message: string): boolean {
+	if (form === '') {
+		return true
+	}
+	return alike(tags(form), tags(message))
+}
+
 /** NUMBER is the conversion a placeholder ends in when it writes a number rather than text. */
 const NUMBER = /[deEfgGiu]$/
 
@@ -152,7 +177,7 @@ export function unformatted(template: string): string[] {
 }
 
 /**
- * Returns every message whose translation names placeholders its message does not.
+ * Returns every message whose translation names placeholders or tags its message does not.
  * @param source - The catalogue as PO text.
  * @param template - The template naming every message and the placeholders it carries.
  * @returns The keys whose translation would not render.
@@ -167,8 +192,10 @@ export function mismatched(source: string, template: string): string[] {
 				continue
 			}
 			const plural = entry.msgid_plural ?? msgid
-			const matches = answer.msgstr.every((form, at) =>
-				answersPlaceholders(form, at === 0 ? msgid : plural))
+			const matches = answer.msgstr.every((form, at) => {
+				const message = at === 0 ? msgid : plural
+				return answersPlaceholders(form, message) && answersTags(form, message)
+			})
 			if (!matches) {
 				broken.push(keyOf(context, msgid))
 			}

gottext/test/build.test.ts

@@ -597,6 +597,141 @@ msgstr[1] "%(total)d entradas"
 	expect(mismatched(broken, naming)).toEqual(['%(count)d post'])
 })
 
+test('names a translation adding a tag its message does not carry', () => {
+	const naming = 'msgid "<notes>x</notes> y"\nmsgstr ""\n'
+	const added = 'msgid "<notes>x</notes> y"\nmsgstr "<notes>x</notes> <extra>y</extra>"\n'
+
+	expect(mismatched(added, naming)).toEqual(['<notes>x</notes> y'])
+})
+
+test('names a translation dropping a tag its message carries', () => {
+	const naming = 'msgid "<notes>x</notes> y"\nmsgstr ""\n'
+	const dropped = 'msgid "<notes>x</notes> y"\nmsgstr "<notes>x y"\n'
+
+	expect(mismatched(dropped, naming)).toEqual(['<notes>x</notes> y'])
+})
+
+test('names a translation renaming a tag its message carries', () => {
+	const naming = 'msgid "<notes>x</notes> y"\nmsgstr ""\n'
+	const renamed = 'msgid "<notes>x</notes> y"\nmsgstr "<note>x</note> y"\n'
+
+	expect(mismatched(renamed, naming)).toEqual(['<notes>x</notes> y'])
+})
+
+test('names a translation repeating a tag its message carries', () => {
+	const naming = 'msgid "<notes>x</notes> y"\nmsgstr ""\n'
+	const repeated = 'msgid "<notes>x</notes> y"\nmsgstr "<notes>x</notes> <notes>y</notes>"\n'
+
+	expect(mismatched(repeated, naming)).toEqual(['<notes>x</notes> y'])
+})
+
+test('names a translation answering an opening and a closing tag with a self closing one', () => {
+	const naming = 'msgid "<notes>x</notes> y"\nmsgstr ""\n'
+	const selfClosed = 'msgid "<notes>x</notes> y"\nmsgstr "<notes/>x y"\n'
+
+	expect(mismatched(selfClosed, naming)).toEqual(['<notes>x</notes> y'])
+})
+
+test('names a translation opening a tag its message carries self closing', () => {
+	const naming = 'msgid "a <br/> b"\nmsgstr ""\n'
+	const opened = 'msgid "a <br/> b"\nmsgstr "a <br> b"\n'
+
+	expect(mismatched(opened, naming)).toEqual(['a <br/> b'])
+})
+
+test('names a translation answering a closing tag with an opening one', () => {
+	const naming = 'msgid "<notes>x</notes> y"\nmsgstr ""\n'
+	const reopened = 'msgid "<notes>x</notes> y"\nmsgstr "<notes>x<notes> y"\n'
+
+	expect(mismatched(reopened, naming)).toEqual(['<notes>x</notes> y'])
+})
+
+test('names a translation closing a tag its message carries self closing', () => {
+	const naming = 'msgid "a <br/> b"\nmsgstr ""\n'
+	const closed = 'msgid "a <br/> b"\nmsgstr "a </br> b"\n'
+
+	expect(mismatched(closed, naming)).toEqual(['a <br/> b'])
+})
+
+test('names a translation dropping a tag whose name carries capitals and digits', () => {
+	const naming = 'msgid "<Link2>x</Link2> y"\nmsgstr ""\n'
+	const dropped = 'msgid "<Link2>x</Link2> y"\nmsgstr "x y"\n'
+
+	expect(mismatched(dropped, naming)).toEqual(['<Link2>x</Link2> y'])
+})
+
+test('names a translation whose plural form drops a tag', () => {
+	const naming = `msgid "<notes>one</notes> post"
+msgid_plural "<notes>many</notes> posts"
+msgstr[0] ""
+msgstr[1] ""
+`
+	const broken = `msgid "<notes>one</notes> post"
+msgid_plural "<notes>many</notes> posts"
+msgstr[0] "<notes>uno</notes> entrada"
+msgstr[1] "<notes>muchas entradas"
+`
+
+	expect(mismatched(broken, naming)).toEqual(['<notes>one</notes> post'])
+})
+
+test('names a translation whose singular form repeats a tag', () => {
+	const naming = `msgid "<notes>one</notes> post"
+msgid_plural "<notes>many</notes> posts"
+msgstr[0] ""
+msgstr[1] ""
+`
+	const broken = `msgid "<notes>one</notes> post"
+msgid_plural "<notes>many</notes> posts"
+msgstr[0] "<notes>uno</notes> <notes>uno</notes>"
+msgstr[1] "<notes>muchas</notes> entradas"
+`
+
+	expect(mismatched(broken, naming)).toEqual(['<notes>one</notes> post'])
+})
+
+test('reads the tags of each plural form against the form it answers', () => {
+	const naming = `msgid "one post"
+msgid_plural "<notes>many</notes> posts"
+msgstr[0] ""
+msgstr[1] ""
+`
+	const answered = `msgid "one post"
+msgid_plural "<notes>many</notes> posts"
+msgstr[0] "una entrada"
+msgstr[1] "<notes>muchas</notes> entradas"
+`
+
+	expect(mismatched(answered, naming)).toEqual([])
+})
+
+test('passes a translation moving a tag its message carries', () => {
+	const naming = 'msgid "<notes>x</notes> <link>y</link>"\nmsgstr ""\n'
+	const moved = 'msgid "<notes>x</notes> <link>y</link>"\nmsgstr "<link>y</link> <notes>x</notes>"\n'
+
+	expect(mismatched(moved, naming)).toEqual([])
+})
+
+test('passes a translation carrying spaces inside a tag', () => {
+	const naming = 'msgid "<notes>x</notes> y"\nmsgstr ""\n'
+	const spaced = 'msgid "<notes>x</notes> y"\nmsgstr "<notes  >x</notes  > y"\n'
+
+	expect(mismatched(spaced, naming)).toEqual([])
+})
+
+test('passes an empty form answering a message carrying tags', () => {
+	const naming = 'msgid "<notes>x</notes> y"\nmsgstr ""\n'
+
+	expect(mismatched(naming, naming)).toEqual([])
+})
+
+test('passes a translation closing a tag before opening it', () => {
+	const naming = 'msgid "<notes>x</notes> y"\nmsgstr ""\n'
+	const closedFirst = 'msgid "<notes>x</notes> y"\nmsgstr "</notes>x<notes> y"\n'
+
+	expect(mismatched(closedFirst, naming)).toEqual([])
+})
+
 test('passes over the metadata entry rather than reading it as a message', () => {
 	const naming = 'msgid ""\nmsgstr ""\n\nmsgid "Older posts"\nmsgstr ""\n'