[TopGit RFC/PATCH v3 11/12] tg-patch: use ui diff when pager is active

[Bert Wesarg <bert.wesarg@googlemail.com>]

diff-tree should be used to generate patches meant for submission
(or non-human consumption). But for pure human inspection some 'eye-candy'
effects could take considerations. Like color, renames, mnemonicprefix,
or noprefix. External diff driver or word-diff. All these are in effect
by using the diff command, when configured in your git config file.
diff-tree does not honor these configure options but its possible to give
them as command line options too. Selecting the plumbing or ui diff driver
is best done automatically, in my opinion. And an active pager is my best
bet that a human will consume the output.

Signed-off-by: Bert Wesarg <bert.wesarg@googlemail.com>

---

I will probably add an overwrite command switch (to enable ui mode even
without an active pager shortly. Because I sometimes pipe the output for
inspection into my editor.

 tg-patch.sh |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/tg-patch.sh b/tg-patch.sh
index 9def6e5..dcce672 100644
--- a/tg-patch.sh
+++ b/tg-patch.sh
@@ -70,7 +70,12 @@ t_tree=$(pretty_tree "$name" $head_from)
 if [ $b_tree = $t_tree ]; then
 	echo "No changes."
 else
-	git diff-tree -p --stat $b_tree $t_tree
+	# use the ui diff command when the pager is active
+	diff_command=diff
+	[ "x$GIT_PAGER_IN_USE" = "x1" ] ||
+		diff_command=diff-tree
+
+	git $diff_command -p --stat $b_tree $t_tree
 fi
 
 echo '-- '
-- 
1.7.3.1.1069.g89486