Delete the cached archive to force a redownload:

rm -rf ~/.helm/cache/archive/cp-helm-charts-0.1.0.tgz 

Do an explicit repo update

helm repo update

Do a debug/dry-run install to force a download:

helm install --debug --dry-run confluent/cp-helm-charts > /dev/null

Look at the specific file in the .tgz archive where I want to see the fix:

tar xfO ~/.helm/cache/archive/cp-helm-charts-0.1.0.tgz cp-helm-charts/charts/cp-kafka/templates/statefulset.yaml | grep -n -C10 volumes:

Compare to the latest version on github, which was modified 8 days ago: https://github.com/confluentinc/cp-helm-charts/blob/master/charts/cp-kafka/templates/statefulset.yaml#L140

The github version has - name: datadir-0. The version Helm pulls just has - name: datadir without the trailing -0.

Why does the .tgz file that Helm pulls not have the latest fix in the master branch version on github? How do I fix this?

FYI, my relevant environment information:

helm version
Client: &version.Version{SemVer:"v2.12.2", GitCommit:"7d2b0c73d734f6586ed222a567c5d103fed435be", GitTreeState:"clean"}
Server: &version.Version{SemVer:"v2.12.2", GitCommit:"7d2b0c73d734f6586ed222a567c5d103fed435be", GitTreeState:"clean"}

helm repo list
NAME        URL                                             
stable      https://kubernetes-charts.storage.googleapis.com
local       http://127.0.0.1:8879/charts                    
confluent   https://confluentinc.github.io/cp-helm-charts/