add check that latest tag is truly a later version

.github/workflows/latest-release-tag.yml

@@ -4,16 +4,90 @@ on:
     types: [published] # This makes it run only when a new released is published
 
 jobs:
-  run:
+  latest-release:
     name: Add/update tag to new release
     runs-on: ubuntu-latest
 
     steps:
     - name: Checkout repository
       uses: actions/checkout@v2
 
+    - name: Check for latest tag
+      id: latest-tag
+      run: |
+        LATEST_TAG=$(git show-ref --tags -d | grep latest^{} | sed 's/refs\/tags\/latest^{}//') || echo 'not found'
+
+        # if 'latest' tag doesn't exist, then set this commit to latest
+        if [[ -z "$LATEST_TAG" ]]
+        then
+          # move on to next task
+          echo "there are no latest tags yet, so I'm going to start by tagging this sha as the latest"
+          exit 0
+        fi
+
+        TAGS=$(git show-ref --tags -d | grep $LATEST_TAG)
+
+        ## get all tags that use the same sha as the latest tag
+        IFS=$'\n'
+        LATEST_TAGS=($TAGS)
+
+        ## loop over those tags and only take action on the one that isn't tagged 'latest'
+        ## that one will have the version number tag
+        for (( i=0; i<${#LATEST_TAGS[@]}; i++ ))
+        do
+          if [[ ${LATEST_TAGS[$i]} != *"latest"* ]]
+          then
+            ## extract just the version from this tag
+            LATEST_RC_TAG=$(echo "${LATEST_TAGS[$i]}" | sed -e 's,.* refs/tags/,,' -e 's/rc//')
+            echo "The current release with the latest tag is version ${LATEST_RC_TAG}"
+
+            ## remove the sha from the latest tag and split into an array- split at the dot
+            IFS=$'.'
+            LATEST_RC_TAG_SPLIT=(${LATEST_RC_TAG})
+
+            ## remove the 'rc' from the current tag if it exists and split into an array at the dot
+            THIS_TAG=($(echo ${{ github.event.release.tag_name }} | sed 's/rc//'))  || echo 'not found'
+
+            # no tag name exists, then exit and don't move on
+            if [[ -z "$THIS_TAG" ]]
+            then
+              echo "no tag was passed in with this action. Not tagging anything"
+              echo "::set-env name=skip_tag::true"
+              exit 0
+            fi
+
+            ## at this point the array should have length of three. If it doesn't, don't tag it, as it's clearly not a version tag.
+            if [[ ${#THIS_TAG[@]} != 3 ]]
+            then
+              echo "This tag does not contain a semantic version number. Skipping."
+              echo "::set-env name=skip_tag::true"
+              exit 0
+            fi
+
+            for (( j=0; j<${#THIS_TAG[@]}; j++ ))
+            do
+              ## if this value is greater than the latest release, then tag it, if it's lower, then stop, if it's
+              ## the same then move on to the next index
+              if [[ ${THIS_TAG[$j]} -gt ${LATEST_RC_TAG_SPLIT[$j]} ]]
+              then
+                echo "This release tag ${{ github.event.release.tag_name }} is the latest. Tagging it"
+                # move on to next task
+                exit 0
+              elif [[ ${THIS_TAG[$j]} -lt ${LATEST_RC_TAG_SPLIT[$j]} ]]
+              then
+                break
+              fi
+            done
+          fi
+        done
+
+        echo "This release tag ${{ github.event.release.tag_name }} is not the latest. Not tagging."
+        # if you've gotten this far, then we don't want to run any tags in the next step
+        echo "::set-env name=skip_tag::true"
+
     - name: Run latest-tag
       uses: EndBug/latest-tag@latest
+      if: (! env.skip_tag )
       with:
         description: Superset latest release
         tag-name: latest

RELEASING/README.md

@@ -135,8 +135,6 @@ Commit the change with the version number, then git tag the version with the rel
     git push upstream ${SUPERSET_VERSION_RC}
 ```
 
-At this point, a git action will run that will automatically tag this release as `latest` so that the most recent release can be referenced simply by this tag instead of looking up the version number.
-
 ## Preparing the release candidate
 
 The first step of preparing an Apache Release is packaging a release candidate
@@ -323,6 +321,8 @@ tag corresponding with the new version. Go to https://github.com/apache/incubato
 click the 3-dot icon and select `Create Release`, paste the content of the ANNOUNCE thread in the
 release notes, and publish the new release.
 
+At this point, a GitHub action will run that will check whether this release's version number is higher than the current 'latest' release. If that condition is true, this release sha will automatically be tagged as `latest` so that the most recent release can be referenced simply by using the 'latest' tag instead of looking up the version number. The existing version number tag will still exist, and can also be used for reference.
+
 ## Post release
 
 #### Refresh documentation website