Implement sparse keyword for containers.list()

[inknos]

@jwhonce I need your guidance here. I made this pr mirroring what the docker behaviour is but this is a change for us. what's your opinion? this is a slowdown, would you rather see sparse=True by default to keep the behavior consistent with the current one?

[openshift-ci]

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[jwhonce]

@inknos We could do something crazy like default to True for libpod and False when compatible is True. Is that too odd for developers? It doesn't break current libpod scripts and it will work as expected for docker scripts.

The other option is to wait for podman 6 and announce it as a breaking change.

[inknos]

We could do something crazy like default to True for libpod and False when compatible is True. Is that too odd for developers? It doesn't break current libpod scripts and it will work as expected for docker scripts.

Right, I am in for the oddness, as it's not odd at all.

(I'll put it down for future-me, who will forget about it)

Having sparse=True has two big benefits. First, not breaking anything, second, it's faster and generally a safer call (especially for scripting). Furthermore, splitting the podman/docker's behaviours is just a developer's decision. We sacrifice 1-1 compatibility for consistency, faster list calls, and fewer failures by retrievals of statuses for hanging containers. In my opinion, giving the option to sparse=False is the best.

The other option is to wait for podman 6 and announce it as a breaking change.

We can always do this if we get a push from the community to unify the behaviours. Then we only need to flip the default.

[inknos]

Fixes: #459
Fixes: #446

[Copilot]

Pull Request Overview

This PR implements a new "sparse" option for containers.list() to better mirror Docker behavior and introduces a "compatible" flag to control the endpoint selection in both list and reload methods. Key changes include:

• Adding new unit tests for container reloads and sparse listing behavior under both libpod and Docker compatibility modes.
• Modifying the reload method in the resource manager to accept additional keyword arguments.
• Updating the containers_manager get and list methods to support the "compatible" flag and adjust the "sparse" default behavior accordingly.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
podman/tests/unit/test_domainmanager.py	Adds tests to verify container reload endpoint resolution with options.
podman/tests/unit/test_containersmanager.py	Introduces tests for sparse listing under various compatibility scenarios.
podman/domain/manager.py	Updates the reload method to accept keyword arguments (including compatible).
podman/domain/containers_manager.py	Adjusts get and list methods to use the "compatible" flag and apply sparse reloads based on mode.

[jwhonce]

LGTM

@Edward5hen Please review and add the "slash lgtm" command in a comment if you agree with the change. TIA