[PATCH] revision: parse "git log -<count>" more carefully

This mistyped command line simply ignores "master" and ends up
showing two commits from the current HEAD:

    $ git log -2master

because we feed "2master" to atoi() without making sure that the
whole string is parsed as an integer.

Use the strtol_i() helper function instead.

Signed-off-by: Junio C Hamano <redacted>
---

 * We may want to wage a war on atoi(), which we sort-of did back
   when strtol_i() and strtoul_ui() helpers were introduced.  Also I
   suspect that many call sites of strtol() and strtoul() may become
   simpler if they are updated to use these helper functions.  Hint,
   hint...

 revision.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/revision.c b/revision.c
index 71e2337..f6a1088 100644
--- a/revision.c
+++ b/revision.c

@@ -1648,8 +1648,10 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->skip_count = atoi(optarg);
 		return argcount;
 	} else if ((*arg == '-') && isdigit(arg[1])) {
-	/* accept -<digit>, like traditional "head" */
-		revs->max_count = atoi(arg + 1);
+		/* accept -<digit>, like traditional "head" */
+		if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
+		    revs->max_count < 0)
+			die("'%s': not a non-negative integer", arg + 1);
 		revs->no_walk = 0;
 	} else if (!strcmp(arg, "-n")) {
 		if (argc <= 1)