Merge branch 'kh/column-reject-negative-padding'

"git column" has been taught to reject negative padding value, as
it would lead to nonsense behaviour including division by zero.

* kh/column-reject-negative-padding:
  column: guard against negative padding
  column: disallow negative padding

Author: gitster

builtin/column.c

@@ -45,6 +45,8 @@ int cmd_column(int argc, const char **argv, const char *prefix)
 	memset(&copts, 0, sizeof(copts));
 	copts.padding = 1;
 	argc = parse_options(argc, argv, prefix, options, builtin_column_usage, 0);
+	if (copts.padding < 0)
+		die(_("%s must be non-negative"), "--padding");
 	if (argc)
 		usage_with_options(builtin_column_usage, options);
 	if (real_command || command) {

column.c

@@ -182,6 +182,8 @@ void print_columns(const struct string_list *list, unsigned int colopts,
 {
 	struct column_options nopts;
 
+	if (opts && (0 > opts->padding))
+		BUG("padding must be non-negative");
 	if (!list->nr)
 		return;
 	assert((colopts & COL_ENABLE_MASK) != COL_AUTO);
@@ -361,6 +363,8 @@ int run_column_filter(int colopts, const struct column_options *opts)
 {
 	struct strvec *argv;
 
+	if (opts && (0 > opts->padding))
+		BUG("padding must be non-negative");
 	if (fd_out != -1)
 		return -1;
 

t/t9002-column.sh

@@ -196,4 +196,15 @@ EOF
 	test_cmp expected actual
 '
 
+test_expect_success 'padding must be non-negative' '
+	cat >input <<\EOF &&
+1 2 3 4 5 6
+EOF
+	cat >expected <<\EOF &&
+fatal: --padding must be non-negative
+EOF
+	test_must_fail git column --mode=column --padding=-1 <input >actual 2>&1 &&
+	test_cmp expected actual
+'
+
 test_done