v3 branch: runtime error

[cukesheep]

I clone the code of branch v3 and build it.
When i ran the realize run command.There is a runtime error:

panic: runtime error: index out of range [0] with length 0

goroutine 1 [running]:
main.run(0xc000172160)
        E:/realize/realize/main.go:65 +0xeef
github.com/urfave/cli.HandleAction({0xb30680?, 0xc05150?}, 0x3?)
        C:/Users/lottu/go/pkg/mod/github.com/urfave/cli@v1.22.14/app.go:524 +0x50
github.com/urfave/cli.Command.Run({{0xbbca69, 0x3}, {0x0, 0x0}, {0xc0000899f0, 0x1, 0x1}, {0x0, 0x0}, {0x0, ...}, ...}, ...)
        C:/Users/lottu/go/pkg/mod/github.com/urfave/cli@v1.22.14/command.go:175 +0x67b
github.com/urfave/cli.(*App).Run(0xc00011e1c0, {0xc0000a03a0, 0x2, 0x2})
        C:/Users/lottu/go/pkg/mod/github.com/urfave/cli@v1.22.14/app.go:277 +0xb87
main.main()
        E:/realize/realize/main.go:54 +0x73f