feat(sync): deprecate sync.useCache and flip its default value (#150)

internal/myks/application.go

@@ -109,6 +109,10 @@ func (a *Application) Init() error {
 	a.includeNamespace = applicationData.Render.IncludeNamespace
 	a.yttPkgDirs = applicationData.YttPkg.Dirs
 
+	if a.useCache {
+		log.Warn().Msg(".sync.useCache is deprecated and will be removed in a future release. Please use 'lazy' flag in vendir config instead.")
+	}
+
 	return nil
 }
 

internal/myks/assets/data-schema.ytt.yaml

@@ -112,12 +112,9 @@ render:
   includeNamespace: false
 #! Configuration options for the sync step.
 sync:
-  #! If true, the sync step is performed only if the vendir.yaml file is changed after the previous sync.
-  #! Decision whether to sync or not is done on a per-directory basis. This allows to completely skip running
-  #! `vendir sync` for directories that are not changed.
-  #! /!\ Be careful when using this option with dynamic versions (e.g. `latest`, or a branch name).
-  #!     If the upstream is updated, but the vendir config is not changed, the sync step will not be performed.
-  useCache: true
+  #! DEPRECATED: use `lazy` flag of vendir instead.
+  #! See https://github.com/carvel-dev/carvel/blob/develop/proposals/vendir/001-lazy-synching-on-stable-config/
+  useCache: false
 #! Myks configuration and runtime data.
 #! Default values for these options are set by myks.
 myks: