diff-tree: update stale in-code comments

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Junio C Hamano committed Jun 2, 2017 at 11:34 UTC 8ba74bfd7c7e11454a15ed6360777e702c438846
1 file changed +5 -3
builtin/diff-tree.c
+5 -3
@@ -127,9 +127,11 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
127 }
128
129 /*
130 - * NOTE! We expect "a ^b" to be equal to "a..b", so we
131 - * reverse the order of the objects if the second one
132 - * is marked UNINTERESTING.
130 + * NOTE! We expect "a..b" to expand to "^a b" but it is
131 + * perfectly valid for revision range parser to yield "b ^a",
132 + * which means the same thing. If we get the latter, i.e. the
133 + * second one is marked UNINTERESTING, we recover the original
134 + * order the user gave, i.e. "a..b", by swapping the trees.
135 */
136 nr_sha1 = opt->pending.nr;
137 switch (nr_sha1) {