"tagfish update" does not pick the latest tag

[mdub]

I tried using "tagfish update, to update from version 0.9.1 of my image to 0.9.2, but it reverted to 0.8.10!

-  registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.9.1 \
+  registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.8.10 \

registry.cowbell.realestate.com.au has recently been upgrade to (a derivative of) the registry:2.3.0 image ... perhaps this broke the "find latest" logic?

Indeed, tagfish tags --latest also seem confused:

$ tagfish tags --latest registry.cowbell.realestate.com.au/cowbell/rea-shipper
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.8.10
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.8.11
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.8.12
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.8.13
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.8.14
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.8.15
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.8.9
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.9.0
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.9.1
registry.cowbell.realestate.com.au/cowbell/rea-shipper:0.9.2

[diist]

The following images are identical, but tagfish thinks they are not:

~/code/buildkite/buildkite-agent-test  test-consolidate 14:28:15
$ docker pull registry.cowbell.realestate.com.au/cowbell/ubuntu-ruby2.3:201605020617
201605020617: Pulling from cowbell/ubuntu-ruby2.3
Digest: sha256:75b08b423670baec92a880075e4043ba26990260c47bb4735d4f054cecd45d3d
Status: Image is up to date for registry.cowbell.realestate.com.au/cowbell/ubuntu-ruby2.3:201605020617

~/code/buildkite/buildkite-agent-test  test-consolidate 14:28:39
$ docker pull registry.cowbell.realestate.com.au/cowbell/ubuntu-ruby2.3:latest
latest: Pulling from cowbell/ubuntu-ruby2.3
Digest: sha256:75b08b423670baec92a880075e4043ba26990260c47bb4735d4f054cecd45d3d
Status: Downloaded newer image for registry.cowbell.realestate.com.au/cowbell/ubuntu-ruby2.3:latest

Here I'm getting tagfish to print out the shas it's getting for those tags:

201605020617:
sha256:71091f9438eed3140f72bace117c2d38cb265f1c22ed22a1d497397ad66002b6

latest:
sha256:feba60db9be8d698c2ae5c608ad02f573fa04d3a9e7d1a981964f1ccc704f732

Not only they are different but they have nothing to do with the shas returned by docker pull

[diist]

The sha returned in the header when hitting the API directly is different than the sha returned by docker pull

curl -I -u user:pass https://registry.cowbell.realestate.com.au/v2/cowbell/ubuntu-ruby2.3/manifests/201605020617
Docker-Content-Digest: sha256:71091f9438eed3140f72bace117c2d38cb265f1c22ed22a1d497397ad66002b6

[diist]

The bug was "re-introduced" here: 5388b29#diff-c928b154ed02c70a8663cdf5104d6c75L34