ipfswatch doesn't fail nicely when a broken link is found

[stkw0]

Checklist

• This is a bug report, not a question. Ask questions on discuss.ipfs.io.
• I have searched on the issue tracker for my bug.
• I am running the latest kubo version or have an issue updating.

Installation method

built from source

Version

Kubo version: 0.21.0
Repo version: 14
System version: amd64/linux
Golang version: go1.20.5

Config

{
  "API": {
    "HTTPHeaders": {}
  },
  "Addresses": {
    "API": "/ip4/127.0.0.1/tcp/5001",
    "Announce": [],
    "AppendAnnounce": [],
    "Gateway": "/ip4/127.0.0.1/tcp/8080",
    "NoAnnounce": [],
    "Swarm": [
      "/ip4/0.0.0.0/tcp/4001",
      "/ip6/::/tcp/4001",
      "/ip4/0.0.0.0/udp/4001/quic",
      "/ip4/0.0.0.0/udp/4001/quic-v1",
      "/ip4/0.0.0.0/udp/4001/quic-v1/webtransport",
      "/ip6/::/udp/4001/quic",
      "/ip6/::/udp/4001/quic-v1",
      "/ip6/::/udp/4001/quic-v1/webtransport"
    ]
  },
  "AutoNAT": {},
  "Bootstrap": [
    "/dnsaddr/bootstrap.libp2p.io/p2p/QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN",
    "/dnsaddr/bootstrap.libp2p.io/p2p/QmQCU2EcMqAqQPR2i9bChDtGNJchTbq5TbXJJ16u19uLTa",
    "/dnsaddr/bootstrap.libp2p.io/p2p/QmbLHAnMoJPWSCR5Zhtx6BHJX9KiKNN6tpvbUcqanj75Nb",
    "/dnsaddr/bootstrap.libp2p.io/p2p/QmcZf59bWwK5XFi76CZX8cbJ4BhTzzA3gU1ZjYZcYW3dwt",
    "/ip4/104.131.131.82/tcp/4001/p2p/QmaCpDMGvV2BGHeYERUEnRQAwe3N8SzbUtfsmvsqQLuvuJ",
    "/ip4/104.131.131.82/udp/4001/quic/p2p/QmaCpDMGvV2BGHeYERUEnRQAwe3N8SzbUtfsmvsqQLuvuJ"
  ],
  "DNS": {
    "Resolvers": {}
  },
  "Datastore": {
    "BloomFilterSize": 0,
    "GCPeriod": "1h",
    "HashOnRead": false,
    "Spec": {
      "mounts": [
        {
          "child": {
            "path": "blocks",
            "shardFunc": "/repo/flatfs/shard/v1/next-to-last/2",
            "sync": true,
            "type": "flatfs"
          },
          "mountpoint": "/blocks",
          "prefix": "flatfs.datastore",
          "type": "measure"
        },
        {
          "child": {
            "compression": "none",
            "path": "datastore",
            "type": "levelds"
          },
          "mountpoint": "/",
          "prefix": "leveldb.datastore",
          "type": "measure"
        }
      ],
      "type": "mount"
    },
    "StorageGCWatermark": 90,
    "StorageMax": "10GB"
  },
  "Discovery": {
    "MDNS": {
      "Enabled": true
    }
  },
  "Experimental": {
    "AcceleratedDHTClient": false,
    "FilestoreEnabled": false,
    "GraphsyncEnabled": false,
    "Libp2pStreamMounting": false,
    "OptimisticProvide": false,
    "OptimisticProvideJobsPoolSize": 0,
    "P2pHttpProxy": false,
    "StrategicProviding": false,
    "UrlstoreEnabled": false
  },
  "Gateway": {
    "APICommands": [],
    "HTTPHeaders": {
      "Access-Control-Allow-Headers": [
        "X-Requested-With",
        "Range",
        "User-Agent"
      ],
      "Access-Control-Allow-Methods": [
        "GET"
      ],
      "Access-Control-Allow-Origin": [
        "*"
      ]
    },
    "NoDNSLink": false,
    "NoFetch": false,
    "PathPrefixes": [],
    "PublicGateways": null,
    "RootRedirect": ""
  },
  "Identity": {
    "PeerID": "12D3KooWGxkgeytLT2tb5A2EmbZuXsmbE2PgnSPYv8R38dicUTV2"
  },
  "Internal": {},
  "Ipns": {
    "RecordLifetime": "",
    "RepublishPeriod": "",
    "ResolveCacheSize": 128
  },
  "Migration": {
    "DownloadSources": [],
    "Keep": ""
  },
  "Mounts": {
    "FuseAllowOther": false,
    "IPFS": "/ipfs",
    "IPNS": "/ipns"
  },
  "Peering": {
    "Peers": null
  },
  "Pinning": {
    "RemoteServices": {}
  },
  "Plugins": {
    "Plugins": null
  },
  "Provider": {
    "Strategy": ""
  },
  "Pubsub": {
    "DisableSigning": false,
    "Router": ""
  },
  "Reprovider": {},
  "Routing": {
    "Methods": null,
    "Routers": null
  },
  "Swarm": {
    "AddrFilters": null,
    "ConnMgr": {},
    "DisableBandwidthMetrics": false,
    "DisableNatPortMap": false,
    "RelayClient": {},
    "RelayService": {},
    "ResourceMgr": {
      "Limits": {}
    },
    "Transports": {
      "Multiplexers": {},
      "Network": {},
      "Security": {}
    }
  }
}

Description

Running ipfswatch breaks when a broken link is found instead of failing nicely. The error message is the next:

2023/07/13 15:19:03 running IPFSWatch on '.' using repo at '/home/stkw0/.ipfs'...
2023/07/13 15:19:03 .
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x558041f36fa8]

goroutine 1 [running]:
main.IsDirectory({0xc000638230?, 0xc00061e858?})
/var/tmp/portage/net-p2p/kubo-0.21.0/work/cmd/ipfswatch/main.go:202 +0x28
main.addTree.func1({0xc000638230, 0xb}, {0xc00061e820?, 0x0?}, {0x0?, 0x0?})
/var/tmp/portage/net-p2p/kubo-0.21.0/work/cmd/ipfswatch/main.go:178 +0x7a
path/filepath.walk({0xc000638230, 0xb}, {0x558042954038, 0xc00061e820}, 0xc000929c18)
/usr/lib/go/src/path/filepath/path.go:480 +0x116
path/filepath.walk({0x558042443350, 0x1}, {0x558042954038, 0xc00061e4e0}, 0xc000929c18)
/usr/lib/go/src/path/filepath/path.go:504 +0x26f
path/filepath.Walk({0x558042443350, 0x1}, 0xc000929c18)
/usr/lib/go/src/path/filepath/path.go:571 +0x6c
main.addTree(0xc0001be5d0?, {0x558042443350?, 0xc000929e40?})
/var/tmp/portage/net-p2p/kubo-0.21.0/work/cmd/ipfswatch/main.go:173 +0x45
main.run({0xc0001be5d0, 0x12}, {0x558042443350, 0x1})
/var/tmp/portage/net-p2p/kubo-0.21.0/work/cmd/ipfswatch/main.go:69 +0x1dc
main.main()
/var/tmp/portage/net-p2p/kubo-0.21.0/work/cmd/ipfswatch/main.go:49 +0xd5

To reproduce this create a broken link (ln -s non_existing_path broken_link) and then run ipfswatch.