After some thought, I have to say that forcing a local strategy for
copy_file/copy_directory is inappropriate. The point of a sandbox is to
catch hermeticity bugs; disabling the sandbox may be useful for
performance, but it's up to the user to do it if they trust us - and
they can do it via flag. The default should be paranoia and safety.
And on the subject of strategies - using a genrule to create an empty
directory fails in environments where genrules run remote by default
(and thus, copy_directory tests fail). We could, of course, set local=1,
but that disables the sandbox and causes scary warnings. Instead, add a
proper empty_directory rule to test with.
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