precheck: Improve rebase detection

REBASE_HEAD will sometimes be left behind in .git after an interactive
rebase concludes (if the last step completed was a squash or edit, for
instance).  Likewise, it may be missing _during_ a rebase, such as when
paused on a break command.

Instead, use the presence of the rebase-merge or rebase-apply
directories as the "rebase in progress" signal.  Note still that
rebase-apply will exist during git-am as well.

These two directories are utilized by the two rebase implementation
backends, so we shouldn't normally expect to see them both at the same
time.

Signed-off-by: Matt Hunter <m@lfurio.us>

1 files changed, 6 insertions, 2 deletions

diff --git a/git-precheck b/git-precheck
index ddea769..2547563 100755
--- a/git-precheck
+++ b/git-precheck
@@ -65,13 +65,17 @@ if ! [ "$(git rev-parse --is-inside-work-tree 2>/dev/null)" = "true" ]; then
 fi
 
 check MERGE_HEAD merge
-check REBASE_HEAD rebase
 check REVERT_HEAD revert
 check CHERRY_PICK_HEAD cherry-pick
 check BISECT_EXPECTED_REV bisect
 
+if [ -e "$(git rev-parse --git-path rebase-merge 2>/dev/null)" ]; then
+    [ -z "$quiet" ] && printf '\e[0;31mrebase in progress\e[0m\n'
+    exit 3
+fi
+
 if [ -e "$(git rev-parse --git-path rebase-apply 2>/dev/null)" ]; then
-    [ -z "$quiet" ] && printf '\e[0;31mrebase-apply (am) found\e[0m\n'
+    [ -z "$quiet" ] && printf '\e[0;31mrebase/am in progress\e[0m\n'
     exit 3
 fi