repack: document --unpack-unreachable option

This was added back in 7e52f56 (gc: do not explode objects which will be immediately pruned, 2012-04-07), but not documented at the time, since it was an internal detail between git-gc and git-repack. However, as people with complicated setups may want to effectively reimplement the steps of git-gc themselves, it is nice for us to document these interfaces. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Jun 13, 2016 at 00:33 UTC 6a7bcb54714c55234a292047ea6bb657bd5ab1b5
1 file changed +6
Documentation/git-repack.txt
+6
@@ -128,6 +128,12 @@ other objects in that pack they already have locally.
128 with `-b` or `repack.writeBitmaps`, as it ensures that the
129 bitmapped packfile has the necessary objects.
130
131 +--unpack-unreachable=<when>::
132 + When loosening unreachable objects, do not bother loosening any
133 + objects older than `<when>`. This can be used to optimize out
134 + the write of any objects that would be immediately pruned by
135 + a follow-up `git prune`.
136 +
137 Configuration
138 -------------
139