crosslink and be more strict with nil/empty

Signed-off-by: Juraci Paixão Kröhling <[email protected]>

config/go.mod

@@ -58,5 +58,12 @@ require (
 	google.golang.org/protobuf v1.36.5 // indirect
 )
 
-// remove after v0.59.0 of autoprop
 replace go.opentelemetry.io/contrib/propagators/autoprop => ../propagators/autoprop
+
+replace go.opentelemetry.io/contrib/propagators/jaeger => ../propagators/jaeger
+
+replace go.opentelemetry.io/contrib/propagators/b3 => ../propagators/b3
+
+replace go.opentelemetry.io/contrib/propagators/aws => ../propagators/aws
+
+replace go.opentelemetry.io/contrib/propagators/ot => ../propagators/ot

config/v0.3.0/propagation.go

@@ -4,20 +4,37 @@
 package config // import "go.opentelemetry.io/contrib/config/v0.3.0"
 
 import (
+	"errors"
+
 	"go.opentelemetry.io/contrib/propagators/autoprop"
 	"go.opentelemetry.io/otel/propagation"
 )
 
+var (
+	errInvalidPropagatorEmpty = errors.New("invalid propagator name: empty")
+	errInvalidPropagatorNil   = errors.New("invalid propagator name: nil")
+)
+
 func propagator(cfg configOptions) (propagation.TextMapPropagator, error) {
 	if cfg.opentelemetryConfig.Propagator == nil {
 		return autoprop.NewTextMapPropagator(), nil
 	}
 
-	names := make([]string, 0, len(cfg.opentelemetryConfig.Propagator.Composite))
+	n := len(cfg.opentelemetryConfig.Propagator.Composite)
+	if n == 0 {
+		return autoprop.NewTextMapPropagator(), nil
+	}
+
+	names := make([]string, 0, n)
 	for _, name := range cfg.opentelemetryConfig.Propagator.Composite {
-		if name != nil && *name != "" {
-			names = append(names, *name)
+		if name == nil {
+			return nil, errInvalidPropagatorNil
 		}
+		if *name == "" {
+			return nil, errInvalidPropagatorEmpty
+		}
+
+		names = append(names, *name)
 	}
 
 	return autoprop.TextMapPropagator(names...)

config/v0.3.0/propagation_test.go

@@ -150,8 +150,8 @@ func TestPropagator(t *testing.T) {
 					},
 				},
 			},
-			want:    propagation.TraceContext{},
-			wantErr: false,
+			want:    nil,
+			wantErr: true,
 		},
 		{
 			name: "unsupported propagator",