fix: round-trip the metronome parentheses attribute

src/private/mx/impl/DirectionWriter.cpp

@@ -469,6 +469,11 @@ void DirectionWriter::emitTempo(const api::TempoData &tempo, core::Direction &di
         return;
     }
 
+    if (tempo.isParenthetical != api::Bool::unspecified)
+    {
+        metronome.setParentheses(myConverter.convert(tempo.isParenthetical));
+    }
+
     core::DirectionType dt{};
     dt.setChoice(core::DirectionTypeChoice::metronome(metronome));
     addDirectionType(std::move(dt), direction);

src/private/mx/impl/MetronomeReader.cpp

@@ -30,6 +30,12 @@ api::TempoData MetronomeReader::getTempoData() const
     myOutTempoData = api::TempoData{};
     // the old core's beatUnitPer is the new core's group; the old core's
     // noteRelationNote (metronome-note based) is group2
+    if (myMetronome.parentheses().has_value())
+    {
+        Converter converter;
+        myOutTempoData.isParenthetical = converter.convert(*myMetronome.parentheses());
+    }
+
     using FirstChoice = core::MetronomeChoice::Kind;
     const auto firstChoice = myBeatUnitPerOrNoteRelationNoteChoice.kind();
 

src/private/mxtest/api/MetronomeApiTest.cpp

@@ -201,4 +201,33 @@ TEST(roundTripMetricModulation, MetronomeApi)
 
 T_END
 
+TEST(roundTripParentheses, MetronomeApi)
+{
+    // <metronome parentheses="yes"> must round-trip via TempoData::isParenthetical.
+    ScoreData score;
+    score.ticksPerQuarter = 100;
+    score.parts.emplace_back();
+    auto &part = score.parts.back();
+    part.measures.emplace_back();
+    auto &measure = part.measures.back();
+    measure.staves.emplace_back();
+    auto &staff = measure.staves.back();
+    staff.directions.emplace_back();
+    auto &direction = staff.directions.back();
+    direction.tempos.emplace_back();
+    auto &tempo = direction.tempos.back();
+    tempo.tempoType = TempoType::beatsPerMinute;
+    tempo.isParenthetical = Bool::yes;
+    tempo.beatsPerMinute.durationName = DurationName::quarter;
+    tempo.beatsPerMinute.beatsPerMinute = 100;
+
+    auto actualScoreData = roundTrip(score);
+
+    const auto &actualTempo =
+        actualScoreData.parts.back().measures.back().staves.back().directions.back().tempos.back();
+    CHECK(actualTempo.isParenthetical == Bool::yes);
+}
+
+T_END
+
 #endif

src/private/mxtest/api/roundtrip-baseline.txt

@@ -414,3 +414,8 @@ synthetic/non-arpeggiate.3.1.xml
 ksuite/k001a_Articulations.xml
 musuite/testNoteAttributes2.xml
 musuite/testNoteAttributes2_ref.xml
+
+# Unblocked by wiring TempoData::isParenthetical: the metronome parentheses
+# attribute now round-trips.
+lysuite/ly31c_MetronomeMarks.xml
+musuite/testTempo1.xml