Support globs in custom/buildpacks builder deps

[dgageot]

Fixes #3826

Signed-off-by: David Gageot david@gageot.net

[codecov]

Codecov Report

Merging #3878 into master will decrease coverage by 0.03%.
The diff coverage is 73.91%.

Impacted Files	Coverage Δ
pkg/skaffold/build/custom/dependencies.go	76.47% <100%> (-6.87%)	⬇️
pkg/skaffold/build/buildpacks/dependencies.go	100% <100%> (ø)	⬆️
pkg/skaffold/build/list/list.go	71.42% <71.42%> (ø)
pkg/skaffold/docker/dependencies.go	72.91% <0%> (-2.09%)	⬇️
...affold/kubernetes/portforward/kubectl_forwarder.go	68.29% <0%> (+2.43%)	⬆️

[briandealwis]

I'm a bit leery of using docker glob semantics for a non-docker builder (viz the docker.WalkWorkspace's use of docker's NewFilePattern).

More broadly, I'm a bit concerned about the different globbing matchers in use. We have our own util.ExpandPathsGlob() and we also pull in github.com/bmatcuk/doublestar for globs elsewhere.

I don't know how these different globs are different. It might make sense to use specific styles (e.g., docker-style for the docker builder), though that can also be confusing.

[briandealwis]

Could we get invert this dependency? It really just uses docker's fileutils.NewPatternMatcher() to process the excludes globs and then does a normal godirwalk.Walk()

[dgageot]

I was trying to make it work and then I definitely was planning on improving the codebase. We have too many functions where we walk the workspace.