git-bisect visualize: work in non-windowed environments better

This teaches "git bisect visualize" to be more useful in non-windowed
environments.

 (1) When no option is given, and $DISPLAY is set, it continues to
     spawn gitk as before;

 (2) When no option is given, and $DISPLAY is unset, "git log" is run
     to show the range of commits between the bad one and the good ones;

 (3) If only "-flag" options are given, "git log <options>" is run.
     E.g. "git bisect visualize --stat"

 (4) Otherwise, all of the given options are taken as the initial part
     of the command line and the commit range expression is given to
     that command.  E.g. "git bisect visualize tig" will run "tig"
     history viewer to show between the bad one and the good ones.

As "visualize" is a bit too long to type, we also give it a shorter
synonym "view".

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

1 files changed, 17 insertions, 2 deletions

diff --git a/git-bisect.sh b/git-bisect.sh
index 7a6521ec3..538524989 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -324,8 +324,23 @@ bisect_next() {
 
 bisect_visualize() {
 	bisect_next_check fail
+
+	if test $# = 0
+	then
+		case "${DISPLAY+set}" in
+		'')	set git log ;;
+		set)	set gitk ;;
+		esac
+	else
+		case "$1" in
+		git*|tig) ;;
+		-*)	set git log "$@" ;;
+		*)	set git "$@" ;;
+		esac
+	fi
+
 	not=$(git for-each-ref --format='%(refname)' "refs/bisect/good-*")
-	eval gitk refs/bisect/bad --not $not -- $(cat "$GIT_DIR/BISECT_NAMES")
+	eval '"$@"' refs/bisect/bad --not $not -- $(cat "$GIT_DIR/BISECT_NAMES")
 }
 
 bisect_reset() {
@@ -449,7 +464,7 @@ case "$#" in
     next)
         # Not sure we want "next" at the UI level anymore.
         bisect_next "$@" ;;
-    visualize)
+    visualize|view)
 	bisect_visualize "$@" ;;
     reset)
         bisect_reset "$@" ;;