Decode DCS appearance template XML

docs/1c-sql-protocol/research/report-template-codec-program.md

@@ -111,6 +111,11 @@ Read-only diagnostic inventory `CommonTemplate` в `upo_test` уже дал тр
 нужен собственный root-aware classifier и отдельный XML decoder; обратная
 запись по-прежнему запрещена до controlled before/after fixture.
 
+Reader реализован в `plugins/1c/parser/appearance_payload.py`: он возвращает
+контейнер, все верхнеуровневые правила `item(parameter, value)` и точный
+outline XML-тегов. Он не разбирает строковое значение style как произвольный
+формат и всегда сообщает `unsupported_until_reverse_codec_fixture` для write.
+
 ## Ближайшая реализация
 
 Первый кодовый результат — resolver, который умеет различать форму и макет,

plugins/1c/parser/appearance_payload.py

@@ -0,0 +1,61 @@
+"""Read-only decoder for 1C DCS appearance-template payloads.
+
+Appearance templates are a distinct XML family (``AppearanceTemplate``), not
+DataCompositionSchema and not a spreadsheet document.  This decoder returns
+only XML-backed rules and preserves the original carrier for any future
+lossless writer work.
+"""
+
+from __future__ import annotations
+
+import xml.etree.ElementTree as ET
+from collections import Counter
+from typing import Any
+
+from .payload import decode_payload_lossless
+
+
+def _local_name(tag: str) -> str:
+    return tag.rsplit("}", 1)[-1]
+
+
+def _child_text(node: ET.Element, name: str) -> str:
+    child = next((item for item in node if _local_name(item.tag) == name), None)
+    return "".join(child.itertext()).strip() if child is not None else ""
+
+
+def inspect_appearance_payload(data: bytes) -> dict[str, Any]:
+    """Decode a compressed appearance-template carrier without changing it."""
+
+    decoded = decode_payload_lossless(data)
+    payload = bytes(decoded.get("payload") or b"")
+    start = payload.find(b"<?xml")
+    if start < 0:
+        start = payload.find(b"<AppearanceTemplate")
+    end_marker = b"</AppearanceTemplate>"
+    end = payload.find(end_marker, start) if start >= 0 else -1
+    if start < 0 or end < 0:
+        return {
+            "status": "undecodable",
+            "container": {"compression": decoded.get("compression"), "raw_bytes": decoded.get("raw_bytes"), "payload_bytes": decoded.get("payload_bytes")},
+            "diagnostics": {"code": "APPEARANCE_XML_NOT_FOUND"},
+        }
+    xml_bytes = payload[start : end + len(end_marker)]
+    try:
+        root = ET.fromstring(xml_bytes.decode("utf-8-sig"))
+    except (UnicodeDecodeError, ET.ParseError) as exc:
+        return {"status": "undecodable", "diagnostics": {"code": "APPEARANCE_XML_INVALID", "message": str(exc)}}
+    if _local_name(root.tag) != "AppearanceTemplate":
+        return {"status": "unsupported", "diagnostics": {"code": "APPEARANCE_ROOT_NOT_CONFIRMED", "xml_root": _local_name(root.tag)}}
+    items = []
+    for ordinal, item in enumerate((node for node in root if _local_name(node.tag) == "item"), start=1):
+        parameter, value = _child_text(item, "parameter"), _child_text(item, "value")
+        items.append({"ordinal": ordinal, "parameter": parameter, "value": value})
+    tag_counts = Counter(_local_name(node.tag) for node in root.iter())
+    return {
+        "status": "ok",
+        "container": {"compression": decoded.get("compression"), "raw_bytes": decoded.get("raw_bytes"), "payload_bytes": decoded.get("payload_bytes"), "xml_offset": start, "xml_bytes": len(xml_bytes), "xml_root": "AppearanceTemplate"},
+        "items": items,
+        "outline": {"tag_counts": dict(sorted(tag_counts.items(), key=lambda item: item[0].casefold()))},
+        "diagnostics": {"write": "unsupported_until_reverse_codec_fixture"},
+    }

tests/1c/test_payload_codec.py

@@ -38,6 +38,7 @@ from parser.bsl_validation import replace_routine_text, routine_blocks, text_sha
 from parser.form_payload import command_handler_links, data_path_reference_from_node, decode_form_payload, dynamic_list_fields, dynamic_list_settings, embedded_table_addition_row, enrich_form_common_semantic, enrich_item_data_paths, enrich_item_reference_semantics, event_handlers, event_handlers_from_node, form_common_semantic, form_item_coverage_summary, section_record_semantic_properties  # noqa: E402
 from parser.form_xml import decode_form_xml  # noqa: E402
 from parser.scd_payload import compare_scd_semantics, inspect_scd_payload, plan_scd_scalar_patch  # noqa: E402
+from parser.appearance_payload import inspect_appearance_payload  # noqa: E402
 from parser.dbnames import parse_dbnames_bytes, parse_dbnames_version_bytes  # noqa: E402
 sys.path.insert(0, str(ROOT / "plugins" / "1c" / "connector"))
 import adapter_1c_server as adapter_server  # noqa: E402
@@ -252,6 +253,18 @@ def test_scd_payload_decoder_reads_xml_after_platform_prefix() -> None:
     assert result["analysis"]["settings_context"] == {"status": "not_present", "sections": {}}
 
 
+def test_appearance_payload_decoder_reads_xml_rules() -> None:
+    xml = """<?xml version="1.0" encoding="UTF-8"?>
+<AppearanceTemplate><item><parameter>Заголовок</parameter><value>style:Title</value></item><style><name>Title</name></style></AppearanceTemplate>"""
+
+    result = inspect_appearance_payload(compress_payload(b"\x00\x01" + xml.encode("utf-8"), "raw_deflate"))
+
+    assert result["status"] == "ok"
+    assert result["items"] == [{"ordinal": 1, "parameter": "Заголовок", "value": "style:Title"}]
+    assert result["outline"]["tag_counts"] == {"AppearanceTemplate": 1, "item": 1, "name": 1, "parameter": 1, "style": 1, "value": 1}
+    assert result["diagnostics"]["write"] == "unsupported_until_reverse_codec_fixture"
+
+
 def test_scd_scalar_patch_preserves_platform_prefix_and_trailer() -> None:
     xml = """<?xml version="1.0" encoding="UTF-8"?>
 <SchemaFile><dataCompositionSchema>