Add test and fix a few things

Still not sure on source, will consult later.

private/bufpkg/bufplugin/bufplugin.go

@@ -76,6 +76,8 @@ func PluginToProtoPluginRegistryType(plugin Plugin) registryv1alpha1.PluginRegis
 			registryType = registryv1alpha1.PluginRegistryType_PLUGIN_REGISTRY_TYPE_MAVEN
 		} else if plugin.Registry().Swift != nil {
 			registryType = registryv1alpha1.PluginRegistryType_PLUGIN_REGISTRY_TYPE_SWIFT
+		} else if plugin.Registry().Python != nil {
+			registryType = registryv1alpha1.PluginRegistryType_PLUGIN_REGISTRY_TYPE_PYTHON
 		}
 	}
 	return registryType

private/bufpkg/bufplugin/bufpluginconfig/bufpluginconfig.go

@@ -487,9 +487,9 @@ type ExternalPythonRegistryConfig struct {
 type ExternalPythonRegistryDependencyConfig struct {
 	// Source is the URL of the Python package.
 	Source string `json:"source,omitempty" yaml:"source,omitempty"`
-	// Package is the name of the Swift package.
+	// Package is the name of the Python package.
 	Package string `json:"package,omitempty" yaml:"package,omitempty"`
-	// Version is the version of the Swift package.
+	// Version is the version of the Python package.
 	Version string `json:"version,omitempty" yaml:"version,omitempty"`
 }
 

private/bufpkg/bufplugin/bufpluginconfig/bufpluginconfig_test.go

@@ -296,6 +296,37 @@ func TestParsePluginConfigSwiftYAML(t *testing.T) {
 	)
 }
 
+func TestParsePluginConfigPythonYAML(t *testing.T) {
+	t.Parallel()
+	pluginConfig, err := ParseConfig(filepath.Join("testdata", "success", "python", "buf.plugin.yaml"))
+	require.NoError(t, err)
+	pluginIdentity, err := bufpluginref.PluginIdentityForString("buf.build/protocolbuffers/python")
+	require.NoError(t, err)
+	require.Equal(
+		t,
+		&Config{
+			Name:            pluginIdentity,
+			PluginVersion:   "v24.0",
+			SourceURL:       "https://github.com/protocolbuffers/protobuf",
+			Description:     "Base types for Python. Generates message and enum types.",
+			OutputLanguages: []string{"python"},
+			Registry: &RegistryConfig{
+				Python: &PythonRegistryConfig{
+					Dependencies: []PythonRegistryDependencyConfig{
+						{
+							Package: "google-protobuf",
+							Version: "v24.0",
+						},
+					},
+				},
+			},
+			SPDXLicenseID: "BSD-3-Clause",
+			LicenseURL:    "https://github.com/protocolbuffers/protobuf/blob/v24.0/LICENSE",
+		},
+		pluginConfig,
+	)
+}
+
 func TestParsePluginConfigOptionsYAML(t *testing.T) {
 	t.Parallel()
 	pluginConfig, err := ParseConfig(filepath.Join("testdata", "success", "options", "buf.plugin.yaml"))

private/bufpkg/bufplugin/bufpluginconfig/config.go

@@ -98,6 +98,7 @@ func newRegistryConfig(externalRegistryConfig ExternalRegistryConfig) (*Registry
 		isNPMEmpty,
 		isMavenEmpty,
 		isSwiftEmpty,
+		isPythonEmpty,
 	} {
 		if !isEmpty {
 			registryCount++
@@ -350,17 +351,17 @@ func newPythonRegistryConfig(externalPythonRegistryConfig *ExternalPythonRegistr
 }
 
 func pythonExternalDependencyToDependencyConfig(externalDep ExternalPythonRegistryDependencyConfig) (PythonRegistryDependencyConfig, error) {
-	if externalDep.Source == "" {
-		return PythonRegistryDependencyConfig{}, errors.New("python runtime dependency requires a non-empty source")
-	}
+	// TODO: not sure on source, is this required?
+	// if externalDep.Source == "" {
+	// 	return PythonRegistryDependencyConfig{}, errors.New("python runtime dependency requires a non-empty source")
+	// }
 	if externalDep.Package == "" {
 		return PythonRegistryDependencyConfig{}, errors.New("python runtime dependency requires a non-empty package name")
 	}
 	if externalDep.Version == "" {
 		return PythonRegistryDependencyConfig{}, errors.New("python runtime dependency requires a non-empty version name")
 	}
-	// Swift SemVers are typically not prefixed with a "v". The Golang semver library requires a "v" prefix.
-	if !semver.IsValid(fmt.Sprintf("v%s", externalDep.Version)) {
+	if !semver.IsValid(externalDep.Version) {
 		return PythonRegistryDependencyConfig{}, fmt.Errorf("python runtime dependency %s:%s does not have a valid semantic version", externalDep.Package, externalDep.Version)
 	}
 	return PythonRegistryDependencyConfig{

private/bufpkg/bufplugin/bufpluginconfig/testdata/success/python/buf.plugin.yaml

@@ -0,0 +1,14 @@
+version: v1
+name: buf.build/protocolbuffers/python
+plugin_version: v24.0
+source_url: https://github.com/protocolbuffers/protobuf
+description: Base types for Python. Generates message and enum types.
+output_languages:
+  - python
+registry:
+  python:
+    deps:
+      - package: 'google-protobuf'
+        version: 'v24.0'
+spdx_license_id: BSD-3-Clause
+license_url: https://github.com/protocolbuffers/protobuf/blob/v24.0/LICENSE