portainer: Update the Stack is broken

Description

Can’t update any stack on 1.15.3. Have to use CLI on host machine

Steps to reproduce the issue:

1. Put any update stack configuration on existing stack
2. press “Update the stack”
3. JS errors in console, stack is not getting updated:

Error: null is not an object (evaluating 'a.length')
removeInvalidEnvVars@https://portainer.teklog.me/js/app.3f88755d.js:46:23448
deployStack@https://portainer.teklog.me/js/app.3f88755d.js:45:10057

Technical details:

• Portainer version: 1.15.3
• Target Docker version (the host/cluster you manage): Docker version 17.09.0-ce, build afdb6d4
• Platform (windows/linux): linux
• Command used to start Portainer (docker run -p 9000:9000 portainer/portainer):

sudo docker service create --name portainer --replicas=1 --constraint 'node.role == manager' --constraint 'node.hostname == m1' --mount type=bind,src=//var/run/docker.sock,dst=/var/run/docker.sock --mount type=bind,src=//var/volumes/portainer,dst=/data --network=proxy --label com.df.distribute=true --label com.df.notify=true --label com.df.port=9000 --label com.df.serviceDomain=<domain name here> --label com.df.servicePath=/ portainer/portainer -H unix:///var/run/docker.sock

• Target Swarm version (if applicable): 1.32
• Browser: Chrome / Safari