Background (Required)

We need a spike to investigate all the commands that this feature will impact and check what changes will be needed in the code. __ 

Previous work for multiple sources:  https://github.com/argoproj/argo-cd/blob/master/docs/proposals/multiple-sources-for-applications.md

• Users should be able to specify multiple sources to add services to the application via the CLI. Argo CD should compile all the sources and reconcile each source individually for creating the application.
• The cli would need to support adding a list of resources instead of just one while creating the application. values field should allow referencing value files from other sources. 
• Upstream issue: https://github.com/argoproj/argo-cd/issues/12318

The argocd CLI that will be affected are:

argocd app create - allow multi source repos to be created
argocd app edit - allow repo to be added, modified, and deleted
argocd app get - make sure that all the sources are outputted
argocd app diff - make sure that the sources are compared
argocd app patch - ditto
argocd app resources
set/unset/sync/rollback - make sure they work

See https://argo-cd.readthedocs.io/en/release-1.8/user-guide/commands/argocd_app/ for full list of commands and check that all commands work as expected (even ones that did not have changes just in case)

Out of scope

Implementation of the feature, writing the proposal

Approach (Required)

• Go through all the commands in https://argo-cd.readthedocs.io/en/stable/user-guide/commands/argocd_app/ and check which ones would be impacted by multiple sources CLI changes. Come up with examples for each.
• Look at the code for the argocd CLI and check what changes are needed code-wise and investigate if there might be anything that blocks work/needs discussion in the community/affects the scope of the feature. Also check for anything the code touches that we aren't thinking of that might require additional changes. 

Dependencies

NA

Acceptance Criteria (Mandatory)

• Spike is thoroughly investigated and a proposal is ready to be put together upstream. 
• We have a list of all commands we plan to make changes to and examples for each. 

Done Checklist

• Acceptance criteria are met