From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <junkio@cox.net>
Subject: "git-diff-tree -R A B == git-diff-tree B A"?
Date: Fri, 20 May 2005 07:56:08 -0700
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I was preparing a set of tests for diff family because I wanted
to have something that catches screwups I am going to inflict
upon them during the coming couple of days.  One of the tests
accidentally found out that the above is not true in the current
implementation.  Just an excerpt of relevant lines [*1*]:

$ git-diff-tree -r $tree_B $tree_A

+100644 blob 7e426fb079479fd67f6d81f984e4ec649a44bc25 AN
+100644 blob 68a6d8b91da11045cf4aa3a5ab9f2a781c701249 DF/DF
-100644 blob 71420ab81e254145d26d6fc0cddee64c1acd4787 DF
-100644 blob 3c4d8de5fbad08572bab8e10eef8dbb264cf0231 DM

$ git-diff-tree -R $tree_A $tree_B

+100644 blob 7e426fb079479fd67f6d81f984e4ec649a44bc25 AN
-100644 blob 71420ab81e254145d26d6fc0cddee64c1acd4787 DF
+100644 blob 68a6d8b91da11045cf4aa3a5ab9f2a781c701249 DF/DF
-100644 blob 3c4d8de5fbad08572bab8e10eef8dbb264cf0231 DM

I personally don't care about the difference of the order these
are output, but it affects the stability of the test, and also
is inconsistent --- everybody else sorts the entries in the
cache order.

Although I do not see practical problems in this inconsistency,
I am asking you just in case if you care about it.  If there is
a downstream consumer that relies on the ordering of the entries
this may cause problems (diff-helper is OK).

[Footnote]
*1* The trees are taken from t1000-read-tree-m-3way.sh test.