fix: consider padding pattern in sprintf-arguments-mismatch (#1575)

Fixes #1574

Signed-off-by: Anders Eknert <anders@styra.com>

Author: anderseknert

bundle/regal/rules/bugs/sprintf-arguments-mismatch/sprintf_arguments_mismatch.rego

@@ -37,7 +37,9 @@ report contains violation if {
 
 	values_in_arr := count(fn.args[1].value)
 	str_no_escape := replace(format_term.value, "%%", "") # don't include '%%' as it's used to "escape" %
-	values_in_str := strings.count(str_no_escape, "%") - _repeated_explicit_argument_indexes(str_no_escape)
+	num_patterns := strings.count(str_no_escape, "%")
+	num_paddings := strings.count(str_no_escape, "%-*s") # these require 2 arguments to be provided
+	values_in_str := (num_patterns + num_paddings) - _repeated_explicit_argument_indexes(str_no_escape)
 
 	values_in_str != values_in_arr
 

bundle/regal/rules/bugs/sprintf-arguments-mismatch/sprintf_arguments_mismatch_test.rego

@@ -157,3 +157,36 @@ test_success_escaped_verbs_are_ignored if {
 
 	r == set()
 }
+
+# verify fix for https://github.com/styrainc/regal/issues/1574
+test_fail_padding_not_accounted_for if {
+	r := rule.report with input as ast.policy(`x := sprintf("%-*s", ["foo"])`)
+
+	r == {{
+		"category": "bugs",
+		"description": "Mismatch in `sprintf` arguments count",
+		"level": "error",
+		"location": {
+			"col": 14,
+			"end": {
+				"col": 29,
+				"row": 3,
+			},
+			"file": "policy.rego",
+			"row": 3,
+			"text": "x := sprintf(\"%-*s\", [\"foo\"])",
+		},
+		"related_resources": [{
+			"description": "documentation",
+			"ref": config.docs.resolve_url("$baseUrl/$category/sprintf-arguments-mismatch", "bugs"),
+		}],
+		"title": "sprintf-arguments-mismatch",
+	}}
+}
+
+# verify fix for https://github.com/styrainc/regal/issues/1574
+test_success_padding_accounted_for if {
+	r := rule.report with input as ast.policy(`x := sprintf("%-*s", [2, "foo"])`)
+
+	r == set()
+}