bash-prompt.sh: show where rebase is at when stopped

When a rebase stops (e.g. interrupted by a merge conflict), it could
be useful to know how far a rebase has progressed and how many
commits in total this rebase will apply. Teach the __git_ps1()
command to display the number of commits so far applied and the
total number of commits to be applied, like this:

  ((3ec0a6a...)|REBASE 2/5)

In the example above the rebase has stopped at the second commit due to
a merge conflict and there are a total number of five commits to be
applied by this rebase.

This information can be already obtained from the following files which are
being generated during the rebase:

    GIT_DIR/.git/rebase-merge/msgnum (git-rebase--merge.sh)
    GIT_DIR/.git/rebase-merge/end    (git-rebase--merge.sh)
    GIT_DIR/.git/rebase-apply/next   (git-am.sh)
    GIT_DIR/.git/rebase-apply/last   (git-am.sh)

but "rebase -i" does not leave necessary clues.

Implement this feature by doing these three things:

  1) Modify git-rebase--interactive.sh to also create

	GIT_DIR/.git/rebase-merge/msgnum
	GIT_DIR/.git/rebase-merge/end

     files for the number of commits so far applied and the total
     number of commits to be applied.

  2) Modify git-prompt.sh to read and display info from the above
     files.

  3) Update test t9903-bash-prompt.sh to reflect changes introduced
     by this patch.

Signed-off-by: Zoltan Klinger <zoltan.klinger@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-prompt.sh

@@ -263,14 +263,21 @@ __git_ps1 ()
 	else
 		local r=""
 		local b=""
+		local step=""
+		local total=""
+		if [ -d "$g/rebase-merge" ]; then
+			b="$(cat "$g/rebase-merge/head-name")"
+			step=$(cat "$g/rebase-merge/msgnum")
+			total=$(cat "$g/rebase-merge/end")
 			if [ -f "$g/rebase-merge/interactive" ]; then
 				r="|REBASE-i"
-			b="$(cat "$g/rebase-merge/head-name")"
+			else
-		elif [ -d "$g/rebase-merge" ]; then
 				r="|REBASE-m"
-			b="$(cat "$g/rebase-merge/head-name")"
+			fi
 		else
 			if [ -d "$g/rebase-apply" ]; then
+				step=$(cat "$g/rebase-apply/next")
+				total=$(cat "$g/rebase-apply/last")
 				if [ -f "$g/rebase-apply/rebasing" ]; then
 					r="|REBASE"
 				elif [ -f "$g/rebase-apply/applying" ]; then
@@ -308,6 +315,10 @@ __git_ps1 ()
 			}
 		fi
 
+		if [ -n "$step" ] && [ -n "$total" ]; then
+			r="$r $step/$total"
+		fi
+
 		local w=""
 		local i=""
 		local s=""

git-rebase--interactive.sh

@@ -57,6 +57,9 @@ rewritten="$state_dir"/rewritten
 
 dropped="$state_dir"/dropped
 
+end="$state_dir"/end
+msgnum="$state_dir"/msgnum
+
 # A script to set the GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
 # GIT_AUTHOR_DATE that will be used for the commit that is currently
 # being rebased.
@@ -109,7 +112,9 @@ mark_action_done () {
 	sed -e 1d < "$todo" >> "$todo".new
 	mv -f "$todo".new "$todo"
 	new_count=$(git stripspace --strip-comments <"$done" | wc -l)
+	echo $new_count >"$msgnum"
 	total=$(($new_count + $(git stripspace --strip-comments <"$todo" | wc -l)))
+	echo $total >"$end"
 	if test "$last_count" != "$new_count"
 	then
 		last_count=$new_count

t/t9903-bash-prompt.sh

@@ -28,6 +28,10 @@ test_expect_success 'setup for prompt tests' '
 	git checkout -b b2 master &&
 	echo 0 > file &&
 	git commit -m "second b2" file &&
+	echo 00 > file &&
+	git commit -m "another b2" file &&
+	echo 000 > file &&
+	git commit -m "yet another b2" file &&
 	git checkout master
 '
 
@@ -243,10 +247,12 @@ test_expect_success 'prompt - inside bare repository' '
 '
 
 test_expect_success 'prompt - interactive rebase' '
-	printf " (b1|REBASE-i)" > expected
+	printf " (b1|REBASE-i 2/3)" > expected
 	echo "#!$SHELL_PATH" >fake_editor.sh &&
 	cat >>fake_editor.sh <<\EOF &&
-echo "edit $(git log -1 --format="%h")" > "$1"
+echo "exec echo" > "$1"
+echo "edit $(git log -1 --format="%h")" >> "$1"
+echo "exec echo" >> "$1"
 EOF
 	test_when_finished "rm -f fake_editor.sh" &&
 	chmod a+x fake_editor.sh &&
@@ -260,7 +266,7 @@ EOF
 '
 
 test_expect_success 'prompt - rebase merge' '
-	printf " (b2|REBASE-m)" > expected &&
+	printf " (b2|REBASE-m 1/3)" > expected &&
 	git checkout b2 &&
 	test_when_finished "git checkout master" &&
 	test_must_fail git rebase --merge b1 b2 &&
@@ -270,7 +276,7 @@ test_expect_success 'prompt - rebase merge' '
 '
 
 test_expect_success 'prompt - rebase' '
-	printf " ((t2)|REBASE)" > expected &&
+	printf " ((t2)|REBASE 1/3)" > expected &&
 	git checkout b2 &&
 	test_when_finished "git checkout master" &&
 	test_must_fail git rebase b1 b2 &&