imports: wait for fastWalk workers to finish before returning

In some cases walkFn is being called after the fastWalk function has
returned. This often happens when an error was encountered early on in
scanning directories with many entries.

It is caused by fastWalk not waiting for its workers to complete their
work. A sync.WaitGroup is used to wait for all workers to finish when
the function returns.

Updates golang/go#16399

Change-Id: I695d30c18e4878b789520b9d8a650f9688d896ac
Run-TryBot: Brad Fitzpatrick <>
TryBot-Result: Gobot Gobot <>
Reviewed-by: Brad Fitzpatrick <>
1 file changed