bisect: remove "checkout_done" variable used when checking merge bases

Using return values from the following functions:

- check_merge_bases
- check_good_are_ancestors_of_bad

seems simpler.

While at it, let's add some comments to better document the above
functions.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-bisect.sh b/git-bisect.sh
index 69a9a565e0fe655cf09fad8ac693d896ef5d288a..79de7017e88b746971f5a730b8615290bba2890d 100755 (executable)
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -384,6 +384,17 @@ We continue anyway.
 EOF
 }
 
+#
+# "check_merge_bases" checks that merge bases are not "bad".
+#
+# - If one is "good", that's good, we have nothing to do.
+# - If one is "bad", it means the user assumed something wrong
+# and we must exit.
+# - If one is "skipped", we can't know but we should warn.
+# - If we don't know, we should check it out and ask the user to test.
+#
+# In the last case we will return 1, and otherwise 0.
+#
 check_merge_bases() {
        _bad="$1"
        _good="$2"
@@ -398,12 +409,20 @@ check_merge_bases() {
                        handle_skipped_merge_base "$_mb" "$_bad" "$_good"
                else
                        bisect_checkout "$_mb" "a merge base must be tested"
-                       checkout_done=1
-                       return
+                       return 1
                fi
        done
+       return 0
 }
 
+#
+# "check_good_are_ancestors_of_bad" checks that all "good" revs are
+# ancestor of the "bad" rev.
+#
+# If that's not the case, we need to check the merge bases.
+# If a merge base must be tested by the user we return 1 and
+# otherwise 0.
+#
 check_good_are_ancestors_of_bad() {
        test -f "$GIT_DIR/BISECT_ANCESTORS_OK" &&
                return
@@ -417,11 +436,13 @@ check_good_are_ancestors_of_bad() {
 
        _side=$(git rev-list $_good ^$_bad)
        if test -n "$_side"; then
+               # Return if a checkout was done
                check_merge_bases "$_bad" "$_good" "$_skip" || return
-               test "$checkout_done" -eq "1" && return
        fi
 
        : > "$GIT_DIR/BISECT_ANCESTORS_OK"
+
+       return 0
 }
 
 bisect_next() {
@@ -437,8 +458,9 @@ bisect_next() {
                "refs/bisect/skip-*" | tr '\012' ' ') &&
 
        # Maybe some merge bases must be tested first
-       check_good_are_ancestors_of_bad "$bad" "$good" "$skip" || exit
-       test "$checkout_done" -eq "1" && checkout_done='' && return
+       check_good_are_ancestors_of_bad "$bad" "$good" "$skip"
+       # Return now if a checkout has already been done
+       test "$?" -eq "1" && return
 
        # Get bisection information
        BISECT_OPT=''