When “cipd ensure” removes a package, it leaves the entire directory structure behind.

mark@mela zsh% cipd -version
Package name: infra/tools/cipd/mac-amd64
Instance ID:  d03de55ea4a0716c9b4bed4dd6a252d29b4631c8
mark@mela zsh% cat cipd.ensure 
@Subdir ${os}-${arch}
fuchsia/clang/${os}-${arch} latest
mark@mela zsh% cipd ensure -ensure-file cipd.ensure -root . -log-level error
mark@mela zsh% find mac-amd64 -type l | wc -l
     802
mark@mela zsh% find mac-amd64 -type d | wc -l
      64
mark@mela zsh% cat /dev/null > cipd.ensure
mark@mela zsh% cipd ensure -ensure-file cipd.ensure -root . -log-level error
mark@mela zsh% find mac-amd64 -type f | wc -l
       0
mark@mela zsh% find mac-amd64 -type d | wc -l
      64

Note that all of the symbolic links are gone, but the entire directory structure is still there.

In bug 789364 comment 2, Vadim said:

> "ensure" is named this way since it ensures the local state matches whatever is in
> .ensure file. If it starts leaving stuff behind, it is no longer "ensure", but
> something else...

which leads me to believe that the directory detritus is unintentional.