fix(stdlib): check length boundary for lower bound of substring (#4593)

influxdata · Mar 24, 2022 · 7213ec1 · 7213ec1
1 parent 30cb3a7
commit 7213ec1
Show file tree

Hide file tree

Showing 3 changed files with 5 additions and 4 deletions.
diff --git a/libflux/go/libflux/buildinfo.gen.go b/libflux/go/libflux/buildinfo.gen.go
@@ -330,7 +330,7 @@ var sourceHashes = map[string]string{
 	"stdlib/sql/sql.flux":                                                                         "b1d5ed22a2db2046b98d8fb43b8b84e32a613681943260b8990564f12998c7a6",
 	"stdlib/sql/sql_test.flux":                                                                    "a19a2a8d6b75d777e6568768529b811766a2d04ff79fc66c1da4e2babf14a841",
 	"stdlib/strings/strings.flux":                                                                 "101e223716ce769f51d8592d94f752dfe4a05e666f6acb8d333fabb4fb79b253",
-	"stdlib/strings/strings_test.flux":                                                            "e9cf434cf36a6301e3169289050dae2fcf48190e8ff0f7d501431fb79d08851e",
+	"stdlib/strings/strings_test.flux":                                                            "38bfdd79945c5371441c09a59528482a46731762b4ea33b933360fbce6ef4d0a",
 	"stdlib/system/system.flux":                                                                   "cb8b11a1be522b20a3988398c01160f36f442ab90b328181c25c237a731f7372",
 	"stdlib/testing/chronograf/aggregate_window_count_test.flux":                                  "d3d61831ff7a5a8c2bbdbfea515a1b2fe3b0fb72ef6e63101e2b6972b3c52816",
 	"stdlib/testing/chronograf/aggregate_window_mean_test.flux":                                   "ec81285a56699a104e13db8dbef4b75a465aaa591357749c17a1ac43329b3a09",

diff --git a/stdlib/strings/strings.go b/stdlib/strings/strings.go
@@ -357,11 +357,12 @@ var substring = values.NewFunction(
 			s := []rune(v)
 			if a < 0 {
 				a = 0
+			} else if a > int64(len(v)) {
+				a = int64(len(v))
 			}
 			if b > int64(len(v)) {
 				b = int64(len(v))
-			}
-			if b < a {
+			} else if b < a {
 				b = a
 			}
 			return values.NewString(string(s[a:b])), nil

diff --git a/stdlib/strings/strings_test.flux b/stdlib/strings/strings_test.flux
@@ -59,7 +59,7 @@ testcase string_substring {
         {start: 11, end: 100, str: "end out of bounds", want: "bounds"},
         {start: 5, end: -1, str: "end <= start", want: ""},
         // note end <= start here because start is past the actual end of the string
-        {start: 12, end: 100, str: "end <= start", want: ""},
+        {start: 30, end: 100, str: "end <= start", want: ""},
     ]
     want = array.from(rows: bounds |> array.map(fn: (x) => ({_value: x.want})))
     got =