Release not found when fetching dependencies

[porras]

When running shards on an application that depends on f/completion, I get this error:

Updating https://github.com/f/completion.git
git command failed: git log -n 1 4b30b526bed90f010ff9bad1f52df27dfe2a3bef ()

4b30b526bed90f010ff9bad1f52df27dfe2a3bef is the commit that got locked in my shard.lock when I first installed f/completion maybe one month ago, and in effect, it doesn't exist in the repo (but has existed at some point). Has there been any kind of rebase or amend?