Docker: remove a setting when using multiple YAML files - docker

Question

Using Docker Swarm, I keep all my "overrides" in a single yml file like so:
docker stack -c base.yml -c overrides.yml deploy myStack
If my base.yml file defines these deploy limits for serviceA:
serviceA:
. . .
deploy:
resources:
limits: {memory: 1024M}
reservations: {memory: 1024M}
I can easily override in overrides.yml:
serviceA:
deploy:
resources:
limits: {memory: 2048M}
reservations: {memory: 2048M}
This way, my base.yml can change as new versions of the product are released, but any overrides are easily transported from the old to the new version. However, what if I want to REMOVE or delete something defined in base.yml? If I want to keep the reservation, but remove the limits definition by using a second yml file. Is there any way to do this? Currently, I am on yaml version 3.6.
These two options do not work. This (is not parseable):
serviceA:
deploy:
resources:
limits: {memory: }
reservations: {memory: 2048M}
and this (uses the default defined in base.yml):
serviceA:
deploy:
resources:
reservations: {memory: 2048M}

Answer 1

When using multiple docker-compose files, the latter ones get merged into the former ones. That means: You cannot remove definitions, just modify existing ones or add new ones (see https://github.com/docker/compose/issues/3729). A PR to allow that was created and closed without ever being merged.
So all that leaves you with is to remove the limits definition from your base.yml and only have it in your overrides.yml.

Answer 2

fjc provided the actual answer to my question. For the specific case I was interested in, I learned that if you 'override' and set the memory limit to zero (0), that is equivalent to not having set it at all. Not a general workaround, but at least a workaround for this specific case. For instance:
serviceA:
deploy:
resources:
limits: { cpus: '0', memory: '0' }
would effectively not limit either the number of cpus or memory.