Am 12.02.2014 21:20, schrieb Jacob Carlborg:

On 2014-02-12 14:01, Sönke Ludwig wrote:

DUB supports two kinds of schemata for selecting package versions:

  1. SemVer based version identifiers (e.g. ">=1.0.0")
  2. Selection of a specific branch HEAD using the "~" prefix (e.g.

The rationale for supporting the latter is improving the situation for
library developers. In particular it allows library developers to have
their library checked out locally and be able to make and commit
changes to the library while testing those changes in the context of a
separate application package. Usually this would require making a new
version tag for each change, which is not really practical. By
referencing a certain branch of the library instead, this isn't
necessary and development can happen nicely without unnecessary
overhead. So far, so good.

However, all this has some unfortunate side effects. First, due to
laziness or missing awareness many packages in the registry have no
version tags at all, and, partially because of that, many public
packages reference their dependencies by branch instead of by version.
What this means is that any change on a branch of such a package can
break an unknown amount of external code with no possibility for
external packages to at least stay at a particular working commit.

The second issue is that this is prone to introducing version
conflicts. If some library A correctly references library B by version
(say >=1.0.3) and now the developer wants to develop library B in
the context of some application A. To do so, application A, which also
uses library A, references library B as ~master and the developer
checks out the git repository of B and calls dub add-local on it.
But now there is a conflict that generally cannot be easily or
unambiguously resolved. Should the branch or the version constraint
have precedence? Should this work for just ~master or any branch?
What happens with >=1.0.0 vs. a ~2.0.x branch? There are arguments
for and against either way - but no solution we encountered so far was

What finally occurred to us was the following simple, radical solution:

  1. Deprecate ~branch style dependencies and at some point finally
    completely remove support for them
  2. From now on, accept only packages for the registry if they contain
    at least a single version tag


I knew you would be happy to hear that ;)

Yeah, what was missing so far was really just a better alternative. It
took quite a while to switch to a different mindset to get to this
alternative solution.

  1. To still properly support development, allow the developer to
    override locally that a branch should be used for certain packages
    instead of the tagged version that would usually be used (either
    system globally for all projects, or on a per project basis)

Obligatory quote: Destroy!

Personally I would just allow to specify a git repository. A couple of
options would be good like, hash, branch and so on.

Or a path to a cloned git repository where the developer can check out
and branch/revision that fits?