Add a config migration function

main.go

@@ -2,13 +2,18 @@ package main
 
 import (
 	"fmt"
+	"io/ioutil"
 	"os"
+	"path"
 	"strings"
 
 	"github.com/github/gh-cli/command"
+	"github.com/mitchellh/go-homedir"
 )
 
 func main() {
+	migrateConfig()
+
 	if cmd, err := command.RootCmd.ExecuteC(); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		_, isFlagError := err.(command.FlagError)
@@ -18,3 +23,42 @@ func main() {
 		os.Exit(1)
 	}
 }
+
+// if ~/.config/gh is a file, convert it to a directory and place the file
+// into ~/.config/gh/config.yml
+func migrateConfig() {
+	p, _ := homedir.Expand("~/.config/gh")
+	fi, err := os.Stat(p)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "migration error: failed to stat %s", p)
+		return
+	}
+	if fi.Mode().IsDir() {
+		return
+	}
+
+	content, err := ioutil.ReadFile(p)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "migration error: failed to read config at %s", p)
+		return
+	}
+
+	err = os.Remove(p)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "migration error: failed to remove %s", p)
+		return
+	}
+
+	err = os.MkdirAll(p, 0771)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "migration error: failed to mkdir %s", p)
+		return
+	}
+
+	newPath := path.Join(p, "config.yml")
+	err = ioutil.WriteFile(newPath, []byte(content), 0771)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "migration error: failed write to new config path %s", newPath)
+		return
+	}
+}