The app panics while parsing args

[olebedev]

The content of the main file:

func main() {
	swarm := &swarmdb.App{}
	app := cli.App("swarm", "0.1.0.draft")
	app.Command("init", "Initialize a new databse", func(cmd *cli.Cmd) {
		r := cmd.StringArg("REPLICA", "default", "replica UUID")
		cmd.Action = func() {
			err := swarm.Init(r)
			if err != nil {
				swarm.Logger.WithError(err).Error("initialize a new database")
				os.Exit(1)
			}
		}
	})

	app.Run(os.Args)
}

I ran the tool with swarm init test and have got a panic:

panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x40dd1e6]

goroutine 1 [running]:
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*step).run(0xc420010ab0, 0x429a760, 0x447e640)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/flow.go:29 +0x146
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*step).run(0xc420010ba0, 0x429a760, 0x447e640)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/flow.go:21 +0x12e
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*step).run(0xc420010e70, 0x429a760, 0x447e640)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/flow.go:21 +0x12e
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*step).callDo.func1(0xc420010ea0, 0x0, 0x0)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/flow.go:42 +0x4c
panic(0x429a760, 0x447e640)
	/usr/local/Cellar/go/1.9.2/libexec/src/runtime/panic.go:491 +0x283
github.com/olebedev/swarmdb/vendor/github.com/apex/log.(*Logger).log(0x0, 0x3, 0xc4200aa310, 0x42e6f4c, 0x19)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/apex/log/logger.go:142 +0x26
github.com/olebedev/swarmdb/vendor/github.com/apex/log.(*Entry).Error(0xc4200aa310, 0x42e6f4c, 0x19)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/apex/log/entry.go:96 +0x50
main.main.func1.1()
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/cmd/swarm/main.go:31 +0xc0
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*step).callDo(0xc420010ea0, 0x0, 0x0)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/flow.go:45 +0x70
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*step).run(0xc420010ea0, 0x0, 0x0)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/flow.go:17 +0xb3
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*step).run(0xc420010e40, 0x0, 0x0)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/flow.go:21 +0x12e
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*step).run(0xc420010b70, 0x0, 0x0)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/flow.go:21 +0x12e
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*step).run(0xc420051ee0, 0x0, 0x0)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/flow.go:21 +0x12e
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*Cmd).parse(0xc4200b2200, 0xc4200100e0, 0x1, 0x1, 0xc420051ee0, 0xc420010b70, 0xc420010ba0, 0xc42006e168, 0xc42006e120)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/commands.go:473 +0x529
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*Cmd).parse(0xc4200b2100, 0xc4200100d0, 0x2, 0x2, 0xc420051ee0, 0xc420051ee0, 0xc420010ab0, 0xc4200b2101, 0xc420010ab0)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/commands.go:487 +0x7ad
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*Cli).parse(0xc420051f60, 0xc4200100d0, 0x2, 0x2, 0xc420051ee0, 0xc420051ee0, 0xc420010ab0, 0x1, 0x1)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/cli.go:73 +0x102
github.com/olebedev/swarmdb/vendor/github.com/jawher/mow%2ecli.(*Cli).Run(0xc420051f60, 0xc4200100c0, 0x3, 0x3, 0x18, 0xc4200426c0)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/jawher/mow.cli/cli.go:102 +0x134
main.main()
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/cmd/swarm/main.go:37 +0x20b

Why this could happened?

Thanks

[jawher]

Hi,

The panic trace points to a panic raised in:

github.com/olebedev/swarmdb/vendor/github.com/apex/log.(*Logger).log(0x0, 0x3, 0xc4200aa310, 0x42e6f4c, 0x19)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/apex/log/logger.go:142 +0x26
github.com/olebedev/swarmdb/vendor/github.com/apex/log.(*Entry).Error(0xc4200aa310, 0x42e6f4c, 0x19)
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/vendor/github.com/apex/log/entry.go:96 +0x50
main.main.func1.1()
	/usr/local/Cellar/go/workspace/src/github.com/olebedev/swarmdb/cmd/swarm/main.go:31 +0xc0

I couldn't look further into this since swarmdb is apparently a private repo.

As far as I can tell, the issue is not in mow.cli but further down the chain.
The following code works flawlessly:

func main() {
	app := cli.App("swarm", "0.1.0.draft")
	app.Command("init", "Initialize a new databse", func(cmd *cli.Cmd) {
		r := cmd.StringArg("REPLICA", "default", "replica UUID")
		cmd.Action = func() {
			fmt.Printf("r=%s\n", *r)
		}
	})

	app.Run(os.Args)
}

[olebedev]

Oh, sorry it's my bad 🙂

I am closing this. Thank you.