fix regression in plugin generation

private/buf/bufgen/bufgen.go

@@ -26,6 +26,7 @@ import (
 	"github.com/bufbuild/buf/private/bufpkg/bufimage"
 	"github.com/bufbuild/buf/private/bufpkg/bufmodule/bufmoduleref"
 	"github.com/bufbuild/buf/private/bufpkg/bufplugin/bufpluginref"
+	"github.com/bufbuild/buf/private/bufpkg/bufremoteplugin"
 	"github.com/bufbuild/buf/private/pkg/app"
 	"github.com/bufbuild/buf/private/pkg/command"
 	"github.com/bufbuild/buf/private/pkg/connectclient"
@@ -219,7 +220,13 @@ func (p *PluginConfig) GetRemoteHostname() string {
 	if reference, err := bufpluginref.PluginReferenceForString(p.Plugin, 0); err == nil {
 		return reference.Remote()
 	}
-	return p.Remote
+	if p.Remote == "" {
+		return ""
+	}
+	if remote, _, _, _, err := bufremoteplugin.ParsePluginVersionPath(p.Remote); err == nil {
+		return remote
+	}
+	return ""
 }
 
 // ManagedConfig is the managed mode configuration.

private/buf/bufgen/bufgen_test.go

@@ -0,0 +1,32 @@
+// Copyright 2020-2022 Buf Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package bufgen
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPluginConfig_GetRemoteHostname(t *testing.T) {
+	assertPluginConfigRemoteHostname := func(config *PluginConfig, expected string) {
+		t.Helper()
+		assert.Equal(t, config.GetRemoteHostname(), expected)
+	}
+	assertPluginConfigRemoteHostname(&PluginConfig{Plugin: "buf.build/protocolbuffers/go:v1.28.1"}, "buf.build")
+	assertPluginConfigRemoteHostname(&PluginConfig{Plugin: "buf.build/protocolbuffers/go"}, "buf.build")
+	assertPluginConfigRemoteHostname(&PluginConfig{Remote: "buf.build/protocolbuffers/plugins/go:v1.28.1-1"}, "buf.build")
+	assertPluginConfigRemoteHostname(&PluginConfig{Remote: "buf.build/protocolbuffers/plugins/go"}, "buf.build")
+}