Docker Manifest generation is incorrect for Redeploy Disabled repositories.

When a docker image is pushed into a Repository that has Redeploy Disabled, even if it is a valid new tag, the Manifest is generated as V1 instead of V2 and causes deprecation warnings.

Reproduce

Create a new docker image. The following is enough for a Dockerfile:

FROM alpine

RUN echo "Hello World" > hello.txt

Build and tag the image:

docker build -t nexus/hello-test:1 .

Login as necessary and then push the image:

docker push nexus/hello-test:1

No warnings should be displayed and a manifest will be created in Nexus with type:

application/vnd.docker.distribution.manifest.v2+json

Tag a new version:

docker tag nexus/hello-test:1 nexus/hello-test:2

Push this version:

docker push nexus/hello-test:2

The following Warning will be shown:

[DEPRECATION NOTICE] registry v2 schema1 support will be removed in an upcoming release. Please contact admins of the 192.168.1.121:9001 registry NOW to avoid future disruption.

The newly generated manifest will incorrectly have a type of:

application/vnd.docker.distribution.manifest.v1+prettyjws

This is now subject to deprecation and there is no reason that it should be a V1 manifest.

If the repository is set to Allow Redeploy, this does not occur and the v2 manifest is generated correctly.