type mismatch panic on ipfs add

[whyrusleeping]

Verision
./ipfs version --all
go-ipfs version: 0.4.14-dev-eca0486e1
Repo version: 6
System version: amd64/linux
Golang version: go1.9.4

Output

IPFS_PATH="/data/ipfsrepo"  IPFS_FD_MAX="4096" ./ipfs add --progress --local --nocopy --fscache --quieter --recursive mirror/
 
 849.23 GB / 849.35 GB [==========================================================================================================================================]  99.99% 0s
panic: interface conversion: interface {} is cmdkit.Error, not *coreunix.AddedObject

goroutine 70 [running]:
github.com/ipfs/go-ipfs/core/commands.glob..func7.2(0xc42001a3c0)
        /home/alvaro/gocode/src/github.com/ipfs/go-ipfs/core/commands/add.go:405 +0xa60
created by github.com/ipfs/go-ipfs/core/commands.glob..func7.3
        /home/alvaro/gocode/src/github.com/ipfs/go-ipfs/core/commands/add.go:467 +0xc7

[whyrusleeping]

reported in #3885

[Stebalien]

Effectively, ipfs/go-ipfs-cmds#62. We shouldn't be using the same logic for errors and values.

[rngkll]

Let us know if you need help reproducing the issue, are running the command daily.

We will like to help on fixing this.

[whyrusleeping]

@rngkll I've got a patch that fixes the issue (linked above your comment on github). We're working on determining if its the 'right' fix, or just a hack that works for now that we may regret later. Its an issue in our newly refactored command RPC library.