Bug: dependent chart secrets keys deleted on helm upgrade

[migmartri]

After executing helm upgrade, the keys contained in the dependent MariaDB chart k8s secret file get removed.

To reproduce:

Install for example this Wordpress Chart

You will get two secret files with two keys each.

$ kubectl describe secrets muddled-mink-mariadb muddled-mink-wordpress 
Name:           muddled-mink-mariadb
Namespace:      chart-test
Labels:         app=muddled-mink-mariadb
                chart=mariadb-0.3.0
                heritage=Tiller
                release=muddled-mink
Annotations:    <none>

Type:   Opaque

Data
====
mariadb-password:       0 bytes
mariadb-root-password:  0 bytes


Name:           muddled-mink-wordpress
Namespace:      chart-test
Labels:         app=muddled-mink-wordpress
                chart=wordpress-0.3.0
                heritage=Tiller
                release=muddled-mink
Annotations:    <none>

Type:   Opaque

Data
====
smtp-password:          0 bytes
wordpress-password:     7 bytes

Run an upgrade

helm upgrade muddled-mink .

• Two keys from the MariaDB secret file have being removed.
• One key from the Wordpress file was removed too.

kubectl describe secrets muddled-mink-mariadb muddled-mink-wordpress 
Name:           muddled-mink-mariadb
Namespace:      chart-test
Labels:         app=muddled-mink-mariadb
                chart=mariadb-0.3.0
                heritage=Tiller
                release=muddled-mink
Annotations:    <none>

Type:   Opaque

Data
====


Name:           muddled-mink-wordpress
Namespace:      chart-test
Labels:         app=muddled-mink-wordpress
                chart=wordpress-0.3.0
                heritage=Tiller
                release=muddled-mink
Annotations:    <none>

Type:   Opaque

Data
====
wordpress-password:     7 bytes

And this is the error if you try to re-create the MariaDB pod.

Error syncing pod, skipping: failed to "StartContainer" for "muddled-mink-mariadb" with RunContainerError: "GenerateRunContainerOptions: Couldn't find key mariadb-root-password in Secret default/muddled-mink-mariadb"

I am not sure if this behavior affect other entities like ConfigMaps.