changefeedccl: reject updated option when using Avro's key_only e…

…nvelope

Before this change, we would accept the `WITH updated` option when using Avro's
`WITH envelope=key_only` option but would never actually output any updated
fields. This commit properly rejects the config, which doesn't make any sense.

Release note (backwards-incompatible change): The combination of
CHANGEFEED's format=experimental_avro, envelope=key_only, and updated
is now rejected. This is because the use of key_only prevents any
rows with updated fields from being emitted, so the updated option
is meaningless.

pkg/ccl/changefeedccl/encoder.go

@@ -303,6 +303,10 @@ func newConfluentAvroEncoder(opts map[string]string) (*confluentAvroEncoder, err
 			optEnvelope, opts[optEnvelope], optFormat, optFormatAvro)
 	}
 	_, e.updatedField = opts[optUpdatedTimestamps]
+	if e.updatedField && e.keyOnly {
+		return nil, errors.Errorf(`%s is only usable with %s=%s`,
+			optUpdatedTimestamps, optEnvelope, optEnvelopeWrapped)
+	}
 	_, e.beforeField = opts[optDiff]
 	if e.beforeField && e.keyOnly {
 		return nil, errors.Errorf(`%s is only usable with %s=%s`,

pkg/ccl/changefeedccl/encoder_test.go

@@ -124,15 +124,13 @@ func TestEncoders(t *testing.T) {
 			resolved: `{"resolved":{"string":"1.0000000002"}}`,
 		},
 		`format=experimental_avro,envelope=key_only,updated`: {
-			insert:   `{"a":{"long":1}}->`,
-			delete:   `{"a":{"long":1}}->`,
-			resolved: `{"resolved":{"string":"1.0000000002"}}`,
+			err: `updated is only usable with envelope=wrapped`,
 		},
 		`format=experimental_avro,envelope=key_only,diff`: {
 			err: `diff is only usable with envelope=wrapped`,
 		},
 		`format=experimental_avro,envelope=key_only,updated,diff`: {
-			err: `diff is only usable with envelope=wrapped`,
+			err: `updated is only usable with envelope=wrapped`,
 		},
 		`format=experimental_avro,envelope=row`: {
 			err: `envelope=row is not supported with format=experimental_avro`,