Raise AttributeError (not ImportError) from ydb.opentelemetry.__getattr__

Module __getattr__ raising ImportError broke hasattr()/getattr(default)
introspection of OtelTracingProvider when OpenTelemetry is absent. Raise
AttributeError instead, keeping the install hint in the message; enable_tracing()
still surfaces its own ImportError guidance.

Author: vgvoleg

tests/tracing/test_observability_enable.py

@@ -535,6 +535,22 @@ def test_disable_is_noop_when_plugin_import_fails(self, monkeypatch):
         # Must not raise — silent fallback is documented behavior.
         otel_disable()
 
+    def test_provider_access_raises_attributeerror_when_plugin_import_fails(self, monkeypatch):
+        import sys
+
+        monkeypatch.setitem(sys.modules, "ydb.opentelemetry.plugin", None)
+
+        import ydb.opentelemetry as otel
+
+        # AttributeError (not ImportError) keeps introspection sane...
+        assert hasattr(otel, "OtelTracingProvider") is False
+        sentinel = object()
+        assert getattr(otel, "OtelTracingProvider", sentinel) is sentinel
+
+        # ...while the install hint still rides along on direct access.
+        with pytest.raises(AttributeError, match="OpenTelemetry"):
+            otel.OtelTracingProvider
+
 
 class TestOtelTracingSpanBridge:
     """Cover the ``TracingSpan`` wrapper directly (no SDK glue)."""

ydb/opentelemetry/__init__.py

@@ -40,14 +40,17 @@ def disable_tracing():
 
 def __getattr__(name):
     # Lazily expose the OTel provider so ``from ydb.opentelemetry import
-    # OtelTracingProvider`` works without importing ``opentelemetry`` at
-    # module load time.
+    # OtelTracingProvider`` works without importing ``opentelemetry`` at module
+    # load time. When OTel is missing, raise AttributeError (not ImportError) so
+    # hasattr()/getattr(..., default) introspection behaves normally; the install
+    # hint rides along in the message, and enable_tracing() keeps its own
+    # ImportError guidance for the primary entrypoint.
     if name == "OtelTracingProvider":
         try:
             from ydb.opentelemetry.plugin import OtelTracingProvider
         except ImportError:
-            raise ImportError(
-                "OpenTelemetry packages are required for tracing support. "
+            raise AttributeError(
+                "OtelTracingProvider requires the OpenTelemetry packages. "
                 "Install them with: pip install ydb[opentelemetry]"
             ) from None
         return OtelTracingProvider