fix: part-group round-trip fidelity, and a classifier category for supported-element drops

audit/classify.py

@@ -24,6 +24,8 @@ class in O(n), fully reorder-invariant. See
     D  enum-bug         text/attr value is a known missing enum member
     E  missing-attribute  a partial feature's attribute was dropped
     F  pipeline-error   LOADFAIL / GETDATAFAIL / CREATEFAIL (no actual produced)
+    G  supported-drop   a dropped element class is marked support="full"/"partial"
+                        (an impl round-trip bug or an api.features.xml overstatement)
     unknown            a FAIL that matched none of the above
 """
 
@@ -56,11 +58,12 @@ class in O(n), fully reorder-invariant. See
     "D": "enum bug",
     "E": "missing attribute/element",
     "F": "pipeline error",
+    "G": "supported-element drop",
     "unknown": "unknown",
 }
 
 # Categories that are actionable feature gaps (ranked in the worklist).
-_ACTIONABLE = frozenset({"B", "D", "E"})
+_ACTIONABLE = frozenset({"B", "D", "E", "G"})
 
 
 # --------------------------------------------------------------------------- #
@@ -375,8 +378,18 @@ def support_of(tag: str) -> str | None:
         ):
             cats.append("E")
 
-    # Primary = first match in priority order; the rest are secondary.
-    primary = next((c for c in ("B", "C", "D", "E") if c in cats), None)
+    # G -- a dropped element class the audit marks support="full"/"partial".
+    # Either a genuine impl round-trip bug or an api.features.xml overstatement;
+    # both need human triage (issue #219). Without this the file falls through to
+    # "unknown", since B requires *every* dropped class to be support="none".
+    supported_missing = sorted(t for t in missing if support_of(t) in ("full", "partial"))
+    if supported_missing:
+        cats.append("G")
+
+    # Primary = first match in priority order; the rest are secondary. G is last
+    # so a precise enum/attribute finding still wins when one applies; otherwise
+    # a dropped supported element is surfaced instead of hidden in "unknown".
+    primary = next((c for c in ("B", "C", "D", "E", "G") if c in cats), None)
     if primary is None:
         warn(f"{entry.rel}: unclassified FAIL (missing={rec['missing_elements']}, "
              f"mismatch={rec['mismatch_type']})")
@@ -388,6 +401,8 @@ def support_of(tag: str) -> str | None:
     # Blocking features: what, if fully supported, would unblock this file.
     if primary == "B":
         rec["blocking_features"] = sorted(missing)
+    elif primary == "G":
+        rec["blocking_features"] = supported_missing
     elif primary in ("D", "E") and div is not None and div.element:
         rec["blocking_features"] = [div.element]
 
@@ -464,7 +479,7 @@ def print_summary(report: dict, out_path: Path) -> None:
     total = report["summary"]["total"]
     print(f"Classified {total} files from {report['dump_dir']}\n")
 
-    for cat in ("A", "B", "C", "D", "E", "F", "unknown"):
+    for cat in ("A", "B", "C", "D", "E", "F", "G", "unknown"):
         n = counts.get(cat, 0)
         if n == 0 and cat == "A":
             continue
@@ -473,7 +488,7 @@ def print_summary(report: dict, out_path: Path) -> None:
 
     ranked = _rank_blocking_features(records)
     if ranked:
-        print("\nTop blocking features (ranked by files unblocked; B+D+E):")
+        print("\nTop blocking features (ranked by files unblocked; B+D+E+G):")
         for feat, files, single in ranked[:15]:
             print(f"  {feat:<24}{files:>4} files   ({single} single-blocker)")
 

audit/tests/test_classify.py

@@ -144,6 +144,35 @@ def test_missing_attribute(self) -> None:
         self.assertEqual(rec["primary_category"], "E")
         self.assertEqual(rec["mismatch_type"], "attribute-count")
 
+    def test_supported_element_drop(self) -> None:
+        # backup is support="full" but vanishes. That is not category B (which
+        # needs *every* drop to be support="none"), so it must surface as G
+        # rather than fall through to "unknown".
+        self._pair(
+            "wild/supdrop.xml",
+            _wrap("<backup>1</backup><note><pitch><step>C</step></pitch></note>"),
+            _wrap("<note><pitch><step>C</step></pitch></note>"),
+        )
+        rec = self._classify()["wild/supdrop.xml"]
+        self.assertEqual(rec["primary_category"], "G")
+        self.assertEqual(rec["missing_elements"], ["backup"])
+        self.assertEqual(rec["blocking_features"], ["backup"])
+        self.assertTrue(rec["is_single_blocker"])
+
+    def test_mixed_supported_and_none_drop_is_g(self) -> None:
+        # A supported drop (backup=full) mixed with an unsupported drop
+        # (credit=none) is G, not B -- and only the supported tag is a blocker.
+        self._pair(
+            "wild/mixed.xml",
+            _wrap("<backup>1</backup><credit>c</credit><note/>"),
+            _wrap("<note/>"),
+        )
+        rec = self._classify()["wild/mixed.xml"]
+        self.assertEqual(rec["primary_category"], "G")
+        self.assertEqual(rec["missing_elements"], ["backup", "credit"])
+        self.assertEqual(rec["blocking_features"], ["backup"])
+        self.assertEqual(rec["secondary_categories"], [])
+
     def test_pipeline_error_with_status(self) -> None:
         self._pair("wild/load.xml", _wrap("<note/>"), None)
         self._status("wild/load.xml", "LOADFAIL")

data/api.features.xml

@@ -752,8 +752,12 @@
     <feature name="part-clef" support="none">
       <notes>for-part / part-clef (4.0) not modeled.</notes>
     </feature>
-    <feature name="part-group" support="full">
-      <notes>api::PartGroupData; ScoreReader/ScoreWriter.</notes>
+    <feature name="part-group" support="partial">
+      <attributes>
+        <attribute name="type" support="yes"/>
+        <attribute name="number" support="yes"/>
+      </attributes>
+      <notes>api::PartGroupData via ScoreReader::startPartGroup/ScoreWriter::makePartGroupStart. Round-trips type, number, group-name, group-abbreviation, group-symbol (-&gt;bracketType), group-barline (-&gt;api::GroupBarline), and group-name-display/group-abbreviation-display as best-effort plain text (-&gt;displayName/displayAbbreviation). Partial because group-time and editorial (footnote/level) are not modeled, and formatting attributes on group-name/group-symbol/group-barline/display names (color, default-x, font-*, etc.) are dropped (value only). A part-group start with no matching stop is dropped by design: api::PartGroupData models a complete start..stop span, and an unmatched start is semantically invalid (a constraint beyond XSD).</notes>
     </feature>
     <feature name="part-list" support="full">
       <notes>Drives ScoreData.parts ordering; ScoreReader/ScoreWriter.</notes>

data/synthetic/accent.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/accidental-mark.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/accidental-mark.3.1.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/accidental-text.3.0.xml

@@ -11,7 +11,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/accidental-text.3.1.xml

@@ -11,7 +11,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/accidental.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/accidental.3.1.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/accordion-registration.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/accordion-registration.3.1.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/arpeggiate.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/arpeggiate.3.1.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/arpeggiate.4.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/arrow-style.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/arrow.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/arrow.3.1.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/arrowhead.3.1.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/articulations.3.1.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/assess.4.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/bar-style.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/barline.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/barline.3.1.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/barre.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/bass-alter.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/bass-separator.4.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/bass-step.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/bass.4.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/beam.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/beam.3.1.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/beat-repeat.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>

data/synthetic/beat-type.3.0.xml

@@ -8,7 +8,7 @@
     <score-part id="id1">
       <part-name>x</part-name>
     </score-part>
-    <part-group type="start">
+    <part-group type="stop">
       <footnote>x</footnote>
       <level>x</level>
     </part-group>