Fix ProtobufBundle.MinVersion (#228)

Fixes #227

Signed-off-by: Cody Soyland <[email protected]>

pkg/bundle/bundle.go

@@ -313,13 +313,18 @@ func (b *ProtobufBundle) Timestamps() ([][]byte, error) {
 	return signedTimestamps, nil
 }
 
-func (b *ProtobufBundle) MinVersion(version string) bool {
-	mediaTypeParts := strings.Split(b.Bundle.MediaType, "version=")
-	if len(mediaTypeParts) < 2 {
+// MinVersion returns true if the bundle version is greater than or equal to the expected version.
+func (b *ProtobufBundle) MinVersion(expectVersion string) bool {
+	version, err := getBundleVersion(b.Bundle.MediaType)
+	if err != nil {
 		return false
 	}
 
-	return semver.Compare("v"+mediaTypeParts[1], "v"+version) >= 0
+	if !strings.HasPrefix(expectVersion, "v") {
+		expectVersion = "v" + expectVersion
+	}
+
+	return semver.Compare(version, expectVersion) >= 0
 }
 
 func parseEnvelope(input *protodsse.Envelope) (*Envelope, error) {

pkg/bundle/bundle_test.go

@@ -106,6 +106,39 @@ func Test_getBundleVersion(t *testing.T) {
 	}
 }
 
+func TestMinVersion(t *testing.T) {
+	t.Parallel()
+	for _, tc := range []struct {
+		name            string
+		mediaType       string
+		expectedVersion string
+		ret             bool
+	}{
+		{"old-format", "application/vnd.dev.sigstore.bundle+json;version=0.1", "v0.1", true},
+		{"old-format-unexpected", "application/vnd.dev.sigstore.bundle+json;version=0.1", "v0.2", false},
+		{"old-format-without-v", "application/vnd.dev.sigstore.bundle+json;version=0.1", "0.1", true},
+		{"new-format", "application/vnd.dev.sigstore.bundle.v0.3+json", "v0.1", true},
+		{"new-format-exact", "application/vnd.dev.sigstore.bundle.v0.3+json", "v0.3", true},
+		{"new-format-unexpected", "application/vnd.dev.sigstore.bundle.v0.2+json", "v0.3", false},
+		{"new-format-without-v", "application/vnd.dev.sigstore.bundle.v0.3+json", "0.3", true},
+		{"new-format-without-v-unexpected", "application/vnd.dev.sigstore.bundle.v0.2+json", "0.3", false},
+		{"blank", "", "", false},
+		{"invalid", "garbage", "v0.1", false},
+	} {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			b := &ProtobufBundle{Bundle: &protobundle.Bundle{
+				MediaType: tc.mediaType,
+			}}
+			ret := b.MinVersion(tc.expectedVersion)
+			if tc.ret != ret {
+				t.Fatalf("expected %v, got %v", tc.ret, ret)
+			}
+		})
+	}
+}
+
 func TestMediaTypeString(t *testing.T) {
 	t.Parallel()
 	for _, tc := range []struct {