[PATCH 6/13] Change gitk so that it uses --topo-order rather than --merge-order

[Jon Seymour <jon.seymour@gmail.com>]

This change is made so that gitk --all produces the same result for
every user irrespective of whether git-rev-parse --all produces
the same result for every user. By using --topo-order rather than
--merge-order this can be guaranteed and the existing (non-timestamp dependent)
behaviour of --merge-order can be maintained.

Signed-off-by: Jon Seymour <jon.seymour@gmail.com>
---
Paul, could you review this patch and if you agree, ack it.

The rationale for changing gitk to use --topo-order is that git-rev-list will
produce the same order for --topo-order irrespective of the order of the
start list, whereas git-rev-list --merge-order produces an order that is deliberately
sensitive to the order of the start list.

Linus wants gitk --all to behave the same way, irrespective of what order
git-rev-parse --all produces its output. I want --merge-order to keep its
existing behaviour, so we agreed on this compromise whereby gitk uses
--topo-order rather than --merge-order by default.

My understanding of your code is that you only expect a minimal topological ordering
guarantee and the ordering produced by --topo-order should be sufficient
for your needs - that is, you don't rely on the other aspect of the
--merge-order invariant.

I'll leave it to you and Linus to decide how you want to manage the merge between
your HEAD and Linus'.
---

 gitk |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

19c9032b06b370511ef1091434df0d1d644fee06
diff --git a/gitk b/gitk
--- a/gitk
+++ b/gitk
@@ -37,7 +37,7 @@ proc getcommits {rargs} {
 	set parsed_args $rargs
     }
     if [catch {
-	set commfd [open "|git-rev-list --header --merge-order $parsed_args" r]
+	set commfd [open "|git-rev-list --header --topo-order $parsed_args" r]
     } err] {
 	puts stderr "Error executing git-rev-list: $err"
 	exit 1
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