Old sync config stops working

[dgageot]

I had this sync config working with skaffold beta8:

apiVersion: skaffold/v1beta8
kind: Config
build:
  artifacts:
  - image: myimage
    sync:
      public/*: /app/public

It stopped working with v0.31.0. Looks like when I change a file under public, it's synced to /app/public/public/.

To fix it, I changed the skaffold.yaml to:

apiVersion: skaffold/v1beta11
kind: Config
build:
  artifacts:
  - image: myimage
    sync:
      manual:
      - src: public/*
        dest: /app

Can we do something to fix the backward compatibility?

ping @corneliusweig @balopat

[corneliusweig]

The root cause of this issue is that the former default for sync was to flatten nested directories at the destination, e.g. for public/*: /app/public:

public/a -> /app/public/a

or when using double-star public/**: /app/public:

public/A/B/c -> /app/public/c
public/A/b -> /app/public/b
public/a -> /app/public/a

The latter behavior was a bit surprising for most users.

---

We do give a warning about this breaking change when encountering a double-star pattern. However, I was not aware, that this could also break single-star patterns. I think I can provide a fix for single-star patterns, because they should be reproducible with the new config.
On the other hand, double-star patterns cannot be ported correctly and that was a deliberate break of the existing API.