Finish unfinished French entries that equal their source

After a lupdate refresh, the same-text heuristic fills a new string with
the translation of an existing identical one and marks it unfinished.
In the source-language file that guess is the source text itself, which
is exactly what a mirror run writes, but the script left it alone as
"work in progress": 39 such entries stayed unfinished in qet_fr.ts after
refreshing it on 2026-10-07.

The script now finishes an unfinished translation (or plural with all
forms) that is identical to its source. Unfinished translations with
other text stay untouched. Two fixture messages and a test cover it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

misc/i18n/fixtures/mirror_after.ts

@@ -28,6 +28,19 @@
         <source>Brouillon</source>
         <translation type="unfinished">Brouillon (à revoir)</translation>
     </message>
+    <message>
+        <location filename="../sources/alpha.cpp" line="15"/>
+        <source>Copier</source>
+        <translation>Copier</translation>
+    </message>
+    <message numerus="yes">
+        <location filename="../sources/alpha.cpp" line="16"/>
+        <source>%n page(s)</source>
+        <translation>
+            <numerusform>%n page(s)</numerusform>
+            <numerusform>%n page(s)</numerusform>
+        </translation>
+    </message>
     <message numerus="yes">
         <location filename="../sources/alpha.cpp" line="20"/>
         <source>%n élément(s)</source>

misc/i18n/fixtures/mirror_before.ts

@@ -28,6 +28,19 @@
         <source>Brouillon</source>
         <translation type="unfinished">Brouillon (à revoir)</translation>
     </message>
+    <message>
+        <location filename="../sources/alpha.cpp" line="15"/>
+        <source>Copier</source>
+        <translation type="unfinished">Copier</translation>
+    </message>
+    <message numerus="yes">
+        <location filename="../sources/alpha.cpp" line="16"/>
+        <source>%n page(s)</source>
+        <translation type="unfinished">
+            <numerusform>%n page(s)</numerusform>
+            <numerusform>%n page(s)</numerusform>
+        </translation>
+    </message>
     <message numerus="yes">
         <location filename="../sources/alpha.cpp" line="20"/>
         <source>%n élément(s)</source>

misc/i18n/mirror_source_language.py

@@ -42,7 +42,11 @@ into the translation and the entry is finished. Nothing else changes:
 
   - a translation with text is never touched, whether it is a French
     rendering of an English source, identical to the source, or marked
-    unfinished (a translator's work in progress);
+    unfinished (a translator's work in progress), with one exception:
+    an unfinished translation identical to its source is finished.
+    That is what lupdate's same-text heuristic leaves behind when a new
+    string repeats an existing one, and it is what a mirror run would
+    have written anyway;
   - vanished and obsolete entries are left to lupdate;
   - in a plural message only the empty <numerusform>s are filled;
   - the file stays byte-identical outside the rewritten <translation>
@@ -87,6 +91,7 @@ class SourceError(ValueError):
 class Stats:
     mirrored_messages: int = 0
     mirrored_forms: int = 0
+    finished_identical: int = 0
     unfinished_cleared: int = 0
     kept_translated: int = 0
     kept_identical: int = 0
@@ -94,12 +99,13 @@ class Stats:
     kept_unfinished_with_text: int = 0
 
     def changed(self) -> bool:
-        return self.mirrored_messages > 0
+        return self.mirrored_messages > 0 or self.finished_identical > 0
 
     def summary(self) -> str:
         return (
             f"mirrored {self.mirrored_messages} message(s), "
             f"{self.mirrored_forms} plural form(s), "
+            f"finished {self.finished_identical} identical unfinished, "
             f"cleared {self.unfinished_cleared} unfinished flag(s); kept "
             f"{self.kept_translated} translated, {self.kept_identical} identical, "
             f"{self.kept_vanished} vanished, "
@@ -111,6 +117,18 @@ def _translation_type(attrs: str) -> str:
     return m.group("type") if m else ""
 
 
+def _finish(whole: str, body: str, tm: re.Match, tattrs: str,
+            stats: Stats) -> str:
+    """Drop the unfinished flag of a translation equal to its source."""
+    stats.finished_identical += 1
+    stats.unfinished_cleared += 1
+    start = whole.index(body) + tm.start()
+    old = tm.group(0)
+    new = old.replace(f"<translation{tattrs}>",
+                      f"<translation{TYPE_RE.sub('', tattrs)}>", 1)
+    return whole[:start] + new + whole[start + len(old):]
+
+
 def _mirror_message(match: re.Match, forms: int, stats: Stats) -> str:
     whole = match.group(0)
     attrs, body = match.group("attrs"), match.group("body")
@@ -134,6 +152,8 @@ def _mirror_message(match: re.Match, forms: int, stats: Stats) -> str:
         found = FORM_RE.findall(tbody)
         empty = [f for f in found if f == ""]
         if found and not empty:
+            if ttype == "unfinished" and all(f == source for f in found):
+                return _finish(whole, body, tm, tattrs, stats)
             if ttype == "unfinished":
                 stats.kept_unfinished_with_text += 1
             elif all(f == source for f in found):
@@ -153,6 +173,8 @@ def _mirror_message(match: re.Match, forms: int, stats: Stats) -> str:
             stats.mirrored_forms += forms
     else:
         if tbody != "":
+            if ttype == "unfinished" and tbody == source:
+                return _finish(whole, body, tm, tattrs, stats)
             if ttype == "unfinished":
                 stats.kept_unfinished_with_text += 1
             elif tbody == source:

misc/i18n/test_mirror_source_language.py

@@ -66,6 +66,7 @@ class MirrorText(unittest.TestCase):
         self.assertEqual(out, after)
         self.assertEqual(stats.mirrored_messages, 0)
         self.assertEqual(stats.mirrored_forms, 0)
+        self.assertEqual(stats.finished_identical, 0)
         self.assertEqual(stats.unfinished_cleared, 0)
 
     def test_before_becomes_after(self):
@@ -73,7 +74,8 @@ class MirrorText(unittest.TestCase):
         self.assertEqual(out, read(AFTER))
         self.assertEqual(stats.mirrored_messages, 8)
         self.assertEqual(stats.mirrored_forms, 3)
-        self.assertEqual(stats.unfinished_cleared, 2)
+        self.assertEqual(stats.finished_identical, 2)
+        self.assertEqual(stats.unfinished_cleared, 4)
         self.assertEqual(stats.kept_translated, 1)
         self.assertEqual(stats.kept_identical, 1)
         self.assertEqual(stats.kept_vanished, 2)
@@ -113,6 +115,16 @@ class MirrorText(unittest.TestCase):
             if key[0] == "Beta":
                 self.assertEqual(tr.text, msg.findtext("source"), key)
 
+    def test_unfinished_identical_to_source_is_finished(self):
+        """lupdate's same-text heuristic leaves these behind after a refresh;
+        39 of them appeared in lang/qet_fr.ts on 2026-10-07."""
+        out, _ = m.mirror_text(read(BEFORE))
+        msgs = messages(out)
+        for key in [("Alpha", "Copier"), ("Alpha", "%n page(s)")]:
+            self.assertIsNone(msgs[key].find("translation").get("type"), key)
+        self.assertEqual(msgs[("Alpha", "Brouillon")].find("translation").get("type"),
+                         "unfinished", "a different unfinished text stays unfinished")
+
     def test_multiline_and_spaces_kept(self):
         out, _ = m.mirror_text(read(BEFORE))
         self.assertIn("<translation> Ligne 1\nLigne 2\n</translation>", out)