Fix the version parsing in ChecksumFileEntry.init() so that plugins whose name contain v's can `packer init` (#10760)

* fix
* test

packer/plugin-getter/plugins.go

@@ -305,12 +305,12 @@ func (e ChecksumFileEntry) Arch() string        { return e.arch }
 //
 func (e *ChecksumFileEntry) init(req *Requirement) (err error) {
 	filename := e.Filename
-	res := strings.TrimLeft(filename, req.FilenamePrefix())
+	res := strings.TrimPrefix(filename, req.FilenamePrefix())
 	// res now looks like v0.2.12_x5.0_freebsd_amd64.zip
 
 	e.ext = filepath.Ext(res)
 
-	res = strings.TrimRight(res, e.ext)
+	res = strings.TrimSuffix(res, e.ext)
 	// res now looks like v0.2.12_x5.0_freebsd_amd64
 
 	parts := strings.Split(res, "_")
@@ -326,7 +326,7 @@ func (e *ChecksumFileEntry) init(req *Requirement) (err error) {
 
 func (e *ChecksumFileEntry) validate(expectedVersion string, installOpts BinaryInstallationOptions) error {
 	if e.binVersion != expectedVersion {
-		return fmt.Errorf("wrong version, expected %s ", expectedVersion)
+		return fmt.Errorf("wrong version: '%s' does not match expected %s ", e.binVersion, expectedVersion)
 	}
 	if e.os != installOpts.OS || e.arch != installOpts.ARCH {
 		return fmt.Errorf("wrong system, expected %s_%s ", installOpts.OS, installOpts.ARCH)

packer/plugin-getter/plugins_test.go

@@ -27,6 +27,32 @@ var (
 	pluginFolderWrongChecksums = filepath.Join("testdata", "wrong_checksums")
 )
 
+func TestChecksumFileEntry_init(t *testing.T) {
+	expectedVersion := "v0.3.0"
+	req := &Requirement{
+		Identifier: &addrs.Plugin{
+			Hostname:  "github.com",
+			Namespace: "ddelnano",
+			Type:      "xenserver",
+		},
+	}
+
+	checkSum := &ChecksumFileEntry{
+		Filename: fmt.Sprintf("packer-plugin-xenserver_%s_x5.0_darwin_amd64.zip", expectedVersion),
+		Checksum: "0f5969b069b9c0a58f2d5786c422341c70dfe17bd68f896fcbd46677e8c913f1",
+	}
+
+	err := checkSum.init(req)
+
+	if err != nil {
+		t.Fatalf("ChecksumFileEntry.init failure: %v", err)
+	}
+
+	if checkSum.binVersion != expectedVersion {
+		t.Errorf("failed to parse ChecksumFileEntry properly expected version '%s' but found '%s'", expectedVersion, checkSum.binVersion)
+	}
+}
+
 func TestPlugin_ListInstallations(t *testing.T) {
 
 	type fields struct {