fix(sdk): raise error when named view specifies no instrument name (#2815)

.changelog/5631.fixed

@@ -0,0 +1 @@
+`opentelemetry-sdk`: raise an error when a named `View` is defined without specifying `instrument_name`.

opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/view.py

@@ -68,6 +68,8 @@ class View:
 
         name: This is a metric stream customizing attribute: the name of the
             metric stream. If `None`, the name of the instrument will be used.
+            When `name` is specified, `instrument_name` must also be specified
+            and cannot contain wildcard characters.
 
         description: This is a metric stream customizing attribute: the
             description of the metric stream. If `None`, the description of the instrument will
@@ -119,9 +121,15 @@ def __init__(
             # pylint: disable=broad-exception-raised
             raise Exception(f"Some instrument selection criteria must be provided for View {name}")
 
-        if name is not None and instrument_name is not None and any(c in instrument_name for c in "*?["):
-            # pylint: disable=broad-exception-raised
-            raise Exception(f"View {name} declared with wildcard characters in instrument_name")
+        if name is not None:
+            if instrument_name is None:
+                # pylint: disable=broad-exception-raised
+                raise Exception(
+                    f"View {name} specifies a name but no instrument_name, which may select multiple instruments"
+                )
+            if any(c in instrument_name for c in "*?["):
+                # pylint: disable=broad-exception-raised
+                raise Exception(f"View {name} declared with wildcard characters in instrument_name")
 
         # _name, _description, _aggregation, _exemplar_reservoir_factory and
         # _attribute_keys will be accessed when instantiating a _ViewInstrumentMatch.

opentelemetry-sdk/tests/metrics/test_view.py

@@ -6,6 +6,7 @@
 from unittest import TestCase
 from unittest.mock import Mock
 
+from opentelemetry.sdk.metrics import Counter, MeterProvider
 from opentelemetry.sdk.metrics.view import View
 
 
@@ -113,11 +114,88 @@ def test_view_name(self):
             "instrument_[!a-z]",
             "instrument_[abc]",
             "instrument_[",
+            "[ab]",
         ):
             with self.subTest(wildcard_name=wildcard_name):
-                with self.assertRaises(Exception):
+                with self.assertRaisesRegex(
+                    Exception,
+                    r"View name declared with wildcard characters in instrument_name",
+                ):
                     View(name="name", instrument_name=wildcard_name)
 
         view = View(name="name", instrument_name="instrument_name_1")
         self.assertEqual(view._name, "name")
         self.assertEqual(view._instrument_name, "instrument_name_1")
+
+    def test_view_name_without_instrument_name(self):
+        cases = [
+            ("custom_name", {"instrument_type": Mock}),
+            ("custom_name", {"meter_name": "some_meter"}),
+            ("custom_name", {"instrument_unit": "ms"}),
+            ("custom_name", {"meter_version": "1.0.0"}),
+            (
+                "custom_name",
+                {"meter_schema_url": "https://opentelemetry.io/schemas/1.4.0"},
+            ),
+            ("name", {"instrument_type": Counter}),
+            (
+                "custom_name",
+                {
+                    "instrument_type": Counter,
+                    "meter_name": "some_meter",
+                    "instrument_unit": "ms",
+                },
+            ),
+        ]
+        for name, kwargs in cases:
+            with self.subTest(name=name, **kwargs):
+                with self.assertRaisesRegex(
+                    Exception,
+                    rf"View {name} specifies a name but no instrument_name, which may select multiple instruments",
+                ):
+                    View(name=name, **kwargs)
+
+        with self.subTest(case="meter_provider"):
+            with self.assertRaisesRegex(
+                Exception,
+                r"View name specifies a name but no instrument_name, which may select multiple instruments",
+            ):
+                MeterProvider(views=[View(name="name", instrument_type=Counter)])
+
+    def test_unnamed_view_without_instrument_name(self):
+        view = View(instrument_type=Counter)
+        self.assertIsNone(view._name)
+        self.assertIs(view._instrument_type, Counter)
+        self.assertIsNone(view._instrument_name)
+
+        meter_provider = MeterProvider(views=[view])
+        self.assertIsNotNone(meter_provider)
+
+    def test_view_name_with_concrete_instrument_name(self):
+        mock_instrument = Mock()
+        mock_instrument.configure_mock(name="my_counter")
+
+        view = View(name="custom_name", instrument_name="my_counter")
+        self.assertEqual(view._name, "custom_name")
+        self.assertEqual(view._instrument_name, "my_counter")
+        self.assertTrue(view._match(mock_instrument))
+
+        other_instrument = Mock()
+        other_instrument.configure_mock(name="other_counter")
+        self.assertFalse(view._match(other_instrument))
+
+        view_with_type = View(
+            name="custom_name",
+            instrument_name="my_counter",
+            instrument_type=Mock,
+        )
+        self.assertTrue(view_with_type._match(mock_instrument))
+
+        view_with_counter = View(
+            name="custom_name",
+            instrument_name="my_counter",
+            instrument_type=Counter,
+        )
+        self.assertEqual(view_with_counter._name, "custom_name")
+        self.assertEqual(view_with_counter._instrument_name, "my_counter")
+        self.assertIs(view_with_counter._instrument_type, Counter)