Do not pretend to build Python 2 docker images

we are not actually building these anymore so we should not try to build
everything twice.

Author: saraedum

.ci/push-dockerhub.sh

@@ -26,4 +26,8 @@ if [ -z "$DOCKER_USER" -o -z "$SECRET_DOCKER_PASS" ]; then
 else
   cat "$SECRET_DOCKER_PASS" | docker login -u $DOCKER_USER --password-stdin
   docker push ${DOCKER_NAMESPACE:-sagemath}/$1:$DOCKER_TAG
+
+  # For historic reasons, we also provide a -py3 tag. It's identical to the non-py3 tag.
+  docker tag ${DOCKER_NAMESPACE:-sagemath}/$1:$DOCKER_TAG ${DOCKER_NAMESPACE:-sagemath}/$1:$DOCKER_TAG-py3
+  docker push ${DOCKER_NAMESPACE:-sagemath}/$1:$DOCKER_TAG-py3
 fi

.gitlab-ci.yml

@@ -193,43 +193,3 @@ push-dockerhub-dev:
   script:
     - . .ci/pull-gitlab.sh sagemath-dev
     - sh .ci/push-dockerhub.sh sagemath-dev
-
-.py3:
-  variables:
-    WITH_PYTHON: 3
-    DEFAULT_ARTIFACT_BASE: sagemath/sagemath-dev:develop-py3
-
-build-from-latest-py3:
-  extends:
-    - build-from-latest
-    - .py3
-
-build-from-clean-py3:
-  extends:
-    - build-from-clean
-    - .py3
-
-test-dev-py3:
-  extends:
-    - test-dev
-    - .py3
-
-test-cli-py3:
-  extends:
-    - test-cli
-    - .py3
-
-test-jupyter-py3:
-  extends:
-    - test-jupyter
-    - .py3
-
-push-dockerhub-py3:
-  extends:
-    - push-dockerhub
-    - .py3
-
-push-dockerhub-dev-py3:
-  extends:
-    - push-dockerhub-dev
-    - .py3

docker/README.md

@@ -1,12 +1,12 @@
-[![License: GPL v3](https://img.shields.io/badge/License-GPL%20v3-blue.svg)](https://github.com/sagemath/sage/COPYING.txt) [![Maintained](https://img.shields.io/maintenance/yes/2020.svg)](https://github.com/sagemath/sage/commits/master)
+[![License: GPL v3](https://img.shields.io/badge/License-GPL%20v3-blue.svg)](https://github.com/sagemath/sage/COPYING.txt)
 
 # Supported tags
 
 * `latest` — the stable `master` branch [![GitHub last commit (branch)](https://img.shields.io/github/last-commit/sagemath/sage/master.svg)](https://github.com/sagemath/sage/commits/master) [![GitLab CI](https://gitlab.com/sagemath/sage/badges/master/pipeline.svg)](https://gitlab.com/sagemath/sage/commits/master)
 * `x.x` — all stable releases of Sage are tagged with their version number.
 * `x.x.{beta,rc}x` - betas and release candidates of Sage as [tagged in our git repository](https://github.com/sagemath/sage/tags).
 * `develop` — the current development version of Sage which gets merged into the `master` branch when a new version of Sage is released [![GitHub last commit (branch)](https://img.shields.io/github/last-commit/sagemath/sage/develop.svg)](https://github.com/sagemath/sage/commits/develop) [![GitLab CI](https://gitlab.com/sagemath/sage/badges/develop/pipeline.svg)](https://gitlab.com/sagemath/sage/commits/develop)
-* all the above tags can be complemented by `-py3` for Python 3 based images
+* `-py3` - in the past, we distinguished Python 2 and Python 3 builds. Now, since 9.1, we only provide Python 3 based images so the `-py3` suffix is only there for historic reasons.
 
 # What is SageMath