patch: handle 0 context lines (diff.unified=0) when parsing patches Previously, if there were no context lines, we would just keep updating the ranges and the hunk, but not actually storing the hunk (just overwriting it each time). Thus a diff like this: $ hg diff --config diff.unified=0 diff --git a/bar b/bar --- a/bar +++ b/bar @@ -1,0 +2,1 @@ 1 +change1 @@ -3,0 +5,1 @@ 3 +change2 would come out of the parser like this (change1 is lost): bar: @@ -3,0 +5,1 @@ 3 +change2 This had some really weird side effects for things like commit --interactive, split, etc. Differential Revision: https://phab.mercurial-scm.org/D5743