Question - Base-branch render fails when upstream repo renames a Helm chart path before the PR merges

[dvtsten]

We use argocd-diff-preview in a pattern where application teams maintain their Argo CD Application manifests in a central GitOps repo, and their Helm charts in their own repos. When a team renames their Helm chart directory in their own repo and updates the path: in the Application manifest in the same workflow, argocd-diff-preview fails rendering the base-branch (before) state.

    sources:
    - repoURL: https://git-server/repo.git
      targetRevision: main
    - path: helm
    + path: deployment/helm

The base-branch Application still points to path: helm, but by the time argocd-diff-preview runs, the upstream repo has already renamed helm/ → deployment/helm/ on that branch. The tool tries to render the before state by fetching helm/ from upstream — which no longer exists — and fails:

❌ Application failed with error: failed to get manifests for application my-app [b|clusters/my-cluster/apps/my-app.yaml]: ArgoCD API error (code 2): helm: app path does not exist

The after-state render succeeds. The before-state failure is structural: the upstream repo has moved on, and there is no version of the before state that can be rendered against the current upstream branch.

Is there a supported way to handle this today? If not, would you consider a flag (e.g. --ignore-base-render-errors) or per-Application annotation support to allow the render to continue when only base-branch applications fail, rather than aborting the entire run? There's still value to be had in getting the rendered output, as we use argocd-diff-preview output to then pass on to kubeconform and other linting tools.

[dag-andersen]

Hi @dvtsten
Thank you for the question! Nice to hear that you use it together with kubeconform.

Before we decide whether this needs a new flag, could you share a bit more about how you run argocd-diff-preview?

Specifically:

1. Could you share the pipeline step or command that runs the tool, including the arguments and environment variables you pass?
2. Is argocd-diff-preview running from the central GitOps repo where the Argo CD Application manifests live, or from the application teams' Helm chart repositories?
3. In this example, which repo is passed via --repo or REPO?

That detail matters because the expected setup is a bit different depending on whether the PR is in the GitOps repo or in the resource/chart repo. Once I can see how the pipeline is wired, I can better tell whether this is an unsupported edge case or if there is a configuration/workflow adjustment that would avoid the base render failure 🚀