Merge branch 'mm/rebase-i-post-rewrite-exec' into maint

"git rebase -i" fired post-rewrite hook when it shouldn't (namely,
when it was told to stop sequencing with 'exec' insn).

* mm/rebase-i-post-rewrite-exec:
  t5407: use <<- to align the expected output
  rebase -i: fix post-rewrite hook with failed exec command
  rebase -i: demonstrate incorrect behavior of post-rewrite

git-rebase--interactive.sh

@@ -502,7 +502,7 @@ do_pick () {
 }
 
 do_next () {
-	rm -f "$msg" "$author_script" "$amend" || exit
+	rm -f "$msg" "$author_script" "$amend" "$state_dir"/stopped-sha || exit
 	read -r command sha1 rest < "$todo"
 	case "$command" in
 	"$comment_char"*|''|noop)
@@ -592,9 +592,6 @@ do_next () {
 		read -r command rest < "$todo"
 		mark_action_done
 		printf 'Executing: %s\n' "$rest"
-		# "exec" command doesn't take a sha1 in the todo-list.
-		# => can't just use $sha1 here.
-		git rev-parse --verify HEAD > "$state_dir"/stopped-sha
 		${SHELL:-@SHELL_PATH@} -c "$rest" # Actual execution
 		status=$?
 		# Run in subshell because require_clean_work_tree can die.
@@ -890,7 +887,10 @@ first and then run 'git rebase --continue' again."
 		fi
 	fi
 
-	record_in_rewritten "$(cat "$state_dir"/stopped-sha)"
+	if test -r "$state_dir"/stopped-sha
+	then
+		record_in_rewritten "$(cat "$state_dir"/stopped-sha)"
+	fi
 
 	require_clean_work_tree "rebase"
 	do_rest