dep init fails if a required package is checked out in GOPATH with a version not in origin

[spenczar]

At least, I think that's what's happening here.

This is with dep version 3ef7bf8.

In a project which uses github.com/golang/protobuf, I ran dep init. It errored with this message:

safe write of manifest and lock: error while writing out vendor tree: error while exporting github.com/golang/protobuf: fatal: failed to unpack tree object 32d172e1d23fd527e941c717dee7555aa5948b38
: exit status 128

I ran cd $GOPATH/src/github.com/golang/protobuf, and checked, and yes - I am checked out to that commit:

-> % git rev-parse HEAD
32d172e1d23fd527e941c717dee7555aa5948b38

This happens to be the SHA of the head commit of a branch I was working on, https://github.com/spenczar/protobuf/tree/codegen_convention. It's not yet in the upstream repo.

I ran git checkout master in $GOPATH/src/github.com/golang/protobuf, returned to the original project, ran dep init, and then everything was fine again.

I didn't expect that the state of packages in GOPATH would have an impact on how dep init works (I figured it would treat remotes as the authorities), so I'm making a bug report.

[sdboyer]

Thanks for the clear issue - we've got #216 open on this topic already, so closing 😄

We opted for this as an initial approach because it was the one most in line with vanilla Go users - that their GOPATH is the source of truth.

The WIP spec for the new behavior is in (the document linked from) #277.