cmd/devp2p: Bootnodes are not populated when using crawl subcommand

[ryanschneider]

If I run:

go build ./cmd/devp2p && ./devp2p discv5 crawl /tmp/nodes.json
INFO [01-30|15:50:42.862] New local node record                    seq=1,706,658,642,861 id=66355c79f58631fc ip=127.0.0.1 udp=57825 tcp=0
no input nodes to start crawling

However, the readme seems to indicate that it should work w/ an empty nodeset.

I traced the issue down to this block:

https://github.com/ethereum/go-ethereum/blame/eaac53ec383342fa6ef9c333659d40f7c5dac108/cmd/devp2p/discv4cmd.go#L271

	if commandHasFlag(ctx, bootnodesFlag) {
		bn, err := parseBootnodes(ctx)
		if err != nil {
			exit(err)
		}
		cfg.Bootnodes = bn
	}

The issue is that parseBootnodes is only called if --bootnodes flag is set, but that's also where the standard bootnodes are parsed. Removing the if commandHasFlag check "fixes" the issue and allows me to start crawling, but I'm not sure if that breaks some other command. I see this changed was introduced some time ago in #20094 so it seems like it's been in this state for quite awhile, so I'm not sure how actively maintained/used this tool is.

[fjl]

The tool is actively maintained! The behavior looks like a bug in CLI parsing logic. The crawl command accepts the --bootnodes flag, so it should be detected.