fix: mini compression issues

application/api/answer/services/compression/service.py

@@ -77,8 +77,11 @@ class CompressionService:
             # Get queries to compress
             queries_to_compress = queries[: compress_up_to_index + 1]
 
-            # Check if there are existing compressions
-            existing_compressions = conversation.get("compression_metadata", {}).get(
+            # Check if there are existing compressions. ``compression_metadata``
+            # is a nullable JSONB column, so a never-compressed conversation
+            # reads back as None; ``get(key, {})`` would return that None (the
+            # default only applies to absent keys), so coalesce with ``or {}``.
+            existing_compressions = (conversation.get("compression_metadata") or {}).get(
                 "compression_points", []
             )
 
@@ -201,7 +204,9 @@ class CompressionService:
             (compressed_summary, recent_messages)
         """
         try:
-            compression_metadata = conversation.get("compression_metadata", {})
+            # ``or {}`` guards against a NULL ``compression_metadata`` column
+            # (reads back as None), which would crash the ``.get`` calls below.
+            compression_metadata = conversation.get("compression_metadata") or {}
 
             if not compression_metadata.get("is_compressed"):
                 logger.debug("No compression metadata found - using full history")

tests/test_compression_service.py

@@ -641,6 +641,45 @@ class TestCompressionService:
         # Should log the error
         assert mock_logger.error.called
 
+    def test_compress_conversation_with_null_compression_metadata(
+        self, compression_service, sample_conversation
+    ):
+        """A never-compressed conversation stores ``compression_metadata`` as
+        SQL NULL, which reads back as ``None``. ``dict.get(key, {})`` returns
+        that ``None`` (the default only applies to *absent* keys), so the
+        chained ``.get("compression_points", [])`` raised ``AttributeError:
+        'NoneType' object has no attribute 'get'`` and aborted compression.
+        It must compress normally instead.
+        """
+        sample_conversation["compression_metadata"] = None
+        compression_service.llm.gen.return_value = "<summary>ok</summary>"
+
+        result = compression_service.compress_conversation(
+            conversation=sample_conversation, compress_up_to_index=1
+        )
+
+        assert result.query_index == 1
+        assert "ok" in result.compressed_summary
+
+    @patch("application.api.answer.services.compression.service.logger")
+    def test_get_compressed_context_with_null_compression_metadata(
+        self, mock_logger, compression_service, sample_conversation
+    ):
+        """The same ``None`` value must not crash ``get_compressed_context``.
+        Before the guard it raised, got swallowed by the except, and logged a
+        spurious error while falling back to full history. It should now take
+        the clean no-compression path: full history, no error logged.
+        """
+        sample_conversation["compression_metadata"] = None
+
+        summary, recent = compression_service.get_compressed_context(
+            sample_conversation
+        )
+
+        assert summary is None
+        assert len(recent) == len(sample_conversation["queries"])
+        assert not mock_logger.error.called
+
 
     def test_compression_points_array_limiting(self, compression_service):
         """Test that only the most recent compression points are kept"""