From 727fcb87a82402a6f1e26ee5d9297381c3ed702b Mon Sep 17 00:00:00 2001
From: JS <kureshii@js-xiaomi.localdomain>
Date: Sun, 18 Oct 2026 21:45:52 +0800
Subject: [PATCH] fix(dis7): restore EntityID alias and legacy flat field names

Fixes #88
---
 opendis/dis7.py               |  1 +
 opendis/record/common.py      | 34 ++++++++++++++++++++++
 tests/test_EntityID_compat.py | 54 +++++++++++++++++++++++++++++++++++
 3 files changed, 89 insertions(+)
 create mode 100644 tests/test_EntityID_compat.py

diff --git a/opendis/dis7.py b/opendis/dis7.py
index 1b0036b..2cf5a15 100644
--- a/opendis/dis7.py
+++ b/opendis/dis7.py
@@ -15,6 +15,7 @@
     DEFireFlags,
     WorldCoordinates,
     EntityIdentifier,
+    EntityID,
     EventIdentifier,
     SimulationAddress,
     BeamAntennaPattern,
diff --git a/opendis/record/common.py b/opendis/record/common.py
index 3f35f87..091e459 100644
--- a/opendis/record/common.py
+++ b/opendis/record/common.py
@@ -23,6 +23,7 @@
     "Vector3Float",
     "WorldCoordinates",
     "EntityIdentifier",
+    "EntityID",
     "EulerAngles",
     "SimulationAddress",
     "EventIdentifier",
@@ -53,6 +54,39 @@ def parse(self, inputStream: DataInputStream) -> None:
         self.simulationAddress.parse(inputStream)
         self.entityNumber = inputStream.read_uint16()
 
+    # Legacy EntityID field names, kept for backwards compatibility with
+    # pre-1.1 code and other open-dis implementations. They delegate to the
+    # fields above and do not change the wire format.
+    @property
+    def siteID(self) -> uint16:
+        return self.simulationAddress.site
+
+    @siteID.setter
+    def siteID(self, value: uint16) -> None:
+        self.simulationAddress.site = value
+
+    @property
+    def applicationID(self) -> uint16:
+        return self.simulationAddress.application
+
+    @applicationID.setter
+    def applicationID(self, value: uint16) -> None:
+        self.simulationAddress.application = value
+
+    @property
+    def entityID(self) -> uint16:
+        return self.entityNumber
+
+    @entityID.setter
+    def entityID(self, value: uint16) -> None:
+        self.entityNumber = value
+
+
+# Legacy name for EntityIdentifier (the standard's own shorthand for the
+# §6.2.28 record is "Entity ID"); kept as an alias for backwards
+# compatibility.
+EntityID = EntityIdentifier
+
 
 class EulerAngles(base.Record):
     """6.2.32 Euler Angles record
diff --git a/tests/test_EntityID_compat.py b/tests/test_EntityID_compat.py
new file mode 100644
index 0000000..ff8cee8
--- /dev/null
+++ b/tests/test_EntityID_compat.py
@@ -0,0 +1,54 @@
+"""Backwards compatibility of the EntityID name and its flat field names.
+
+The type of EntityStatePdu.entityID changed from the flat EntityID class to
+EntityIdentifier (see issue #88). EntityID is an alias of EntityIdentifier
+and the flat field names delegate to it, restoring pre-1.1 code without
+changing the wire format.
+"""
+
+import io
+import os
+import unittest
+
+from opendis.dis7 import EntityID, EntityIdentifier
+from opendis.PduFactory import createPduFromFilePath
+from opendis.stream import DataOutputStream
+
+
+class TestEntityIDCompat(unittest.TestCase):
+
+    def setUp(self):
+        testdir = os.path.dirname(os.path.abspath(__file__))
+        os.chdir(testdir)
+
+    def test_alias_identity(self):
+        self.assertIs(EntityID, EntityIdentifier)
+
+    def test_flat_fields_write_through(self):
+        entityID = EntityID()
+        entityID.siteID = 17
+        entityID.applicationID = 23
+        entityID.entityID = 42
+        self.assertEqual(17, entityID.simulationAddress.site)
+        self.assertEqual(23, entityID.simulationAddress.application)
+        self.assertEqual(42, entityID.entityNumber)
+
+    def test_wire_format_unchanged(self):
+        entityID = EntityID()
+        entityID.siteID = 17
+        entityID.applicationID = 23
+        entityID.entityID = 42
+        buffer = io.BytesIO()
+        entityID.serialize(DataOutputStream(buffer))
+        # site 17, application 23, entity number 42, as three big-endian u16
+        self.assertEqual(b"\x00\x11\x00\x17\x00\x2a", buffer.getvalue())
+
+    def test_flat_reads_on_parsed_pdu(self):
+        pdu = createPduFromFilePath("EntityStatePdu-26.raw")
+        self.assertEqual(42, pdu.entityID.siteID)
+        self.assertEqual(4, pdu.entityID.applicationID)
+        self.assertEqual(26, pdu.entityID.entityID)
+
+
+if __name__ == "__main__":
+    unittest.main()