fix subcmd/update

Author: utahta

subcmd/command.go

@@ -4,11 +4,17 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 
+	"github.com/blang/semver"
 	"github.com/pkg/errors"
 )
 
-var Version string
+var (
+	Version string
+
+	reVersion = regexp.MustCompile(`\d+\.\d+\.\d+`)
+)
 
 type (
 	// Command sub command interface
@@ -81,3 +87,11 @@ PYTHONBREW_VERSION_LIB=%s
 	fp.WriteString(env)
 	return nil
 }
+
+func semverVersion() semver.Version {
+	v := Version
+	if loc := reVersion.FindStringIndex(v); loc != nil && loc[0] > 0 {
+		v = v[loc[0]:]
+	}
+	return semver.MustParse(v)
+}

subcmd/update.go

@@ -3,7 +3,6 @@ package subcmd
 import (
 	"flag"
 
-	"github.com/blang/semver"
 	"github.com/pkg/errors"
 	"github.com/rhysd/go-github-selfupdate/selfupdate"
 	"github.com/utahta/pythonbrew/flagset"
@@ -56,7 +55,7 @@ func (c *Update) Run(args []string) error {
 		return nil
 	}
 
-	previous := semver.MustParse(Version)
+	previous := semverVersion()
 	latest, err := selfupdate.UpdateSelf(previous, "utahta/pythonbrew")
 	if err != nil {
 		return errors.Wrap(err, tag)