Support for accept a diff via stdin

Review Request #937 — Created July 30, 2009 and discarded — Latest diff uploaded


Review Board SVN (deprecated)


I've had a few cases where it's more convenient to just build the diff myself based on just a select number of
files, or perhaps cleanup through another script. Seemed simple enough to support piping into postreview.

Been using this patch against an older version for a few months, but it would be easier to just have it included upstream.
Used it to create this review.