1 files changed, 80 insertions, 0 deletions
diff --git a/cmd/git-sw/main.go b/cmd/git-sw/main.go
new file mode 100644
index 0000000..5c098a1
--- /dev/null
+++ b/cmd/git-sw/main.go
@@ -0,0 +1,80 @@
+package main
+
+import (
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+	"unicode"
+)
+
+func main() {
+	gitArgs := []string{"switch"}
+	if requiresDetachFlag(os.Args) {
+		gitArgs = append(gitArgs, "--detach")
+	}
+	firstPositionalArg := true
+	for i, argv := range os.Args {
+		if i == 0 {
+			continue // argv[0] is a program name.
+		}
+		if firstPositionalArg && !strings.HasPrefix(argv, "-") {
+			if isInt(argv) {
+				argv = "feature/" + argv
+			}
+			firstPositionalArg = false
+		}
+		gitArgs = append(gitArgs, argv)
+	}
+
+	cmd := exec.Command("git", gitArgs...)
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	err := cmd.Run()
+	if err != nil {
+		switch err.(type) {
+		case *exec.ExitError:
+			// Do nothing here because Git has already reported the error.
+		default:
+			log.Fatal(err)
+		}
+	}
+
+	os.Exit(cmd.ProcessState.ExitCode())
+}
+
+func requiresDetachFlag(argv []string) bool {
+	argc := len(argv)
+	if argc == 1 {
+		return false
+	}
+	firstArg := argv[1]
+
+	// Example: origin/main, upstream/develop
+	if strings.HasPrefix(firstArg, "origin/") || strings.HasPrefix(firstArg, "upstream/") {
+		return true
+	}
+
+	// Example: 1234, cafebabe
+	if len(firstArg) >= 4 {
+		for _, c := range firstArg {
+			if !unicode.Is(unicode.ASCII_Hex_Digit, c) {
+				return false
+			}
+		}
+		return true
+	}
+
+	return false
+}
+
+func isInt(s string) bool {
+	for _, c := range s {
+		if !unicode.IsDigit(c) {
+			return false
+		}
+	}
+	return true
+}