fix repeating string to emit an error when the result is too large

Author: itchyny

cli/test.yaml

@@ -2853,7 +2853,7 @@
 
 - name: multiply strings
   args:
-    - '[-1.0, -0.5, 0.0, 0.5, 1.0, 1.5, 3.7, 10, 9444732965739290427392 / 4722366482869645213696, 100000000, infinite, -infinite, nan, -1e300, 1e300][] * "abc"'
+    - '(-1.0, -0.5, 0.0, 0.5, 1.0, 1.5, 3.7, 10, nan) * "abc"'
   input: 'null'
   expected: |
     null
@@ -2864,14 +2864,18 @@
     "abc"
     "abcabcabc"
     "abcabcabcabcabcabcabcabcabcabc"
-    "abcabc"
-    null
-    null
-    null
-    null
-    null
     null
 
+- name: multiply strings error
+  args:
+    - -r
+    - '(infinite, 1e300, 720000000) as $n | try ($n * "abc") catch .'
+  input: 'null'
+  expected: |
+    repeat string result too large: "abc" * 1.7976931348623157e+308
+    repeat string result too large: "abc" * 1e+300
+    repeat string result too large: "abc" * 720000000
+
 - name: multiply empty string
   args:
     - '(-9223372036854775808, -1, 0, 0.001, 0.999, 1, 7, 9223372036854775807) * ""'

error.go

@@ -51,6 +51,15 @@ func (err *arrayIndexTooLargeError) Error() string {
 	return "array index too large: " + Preview(err.v)
 }
 
+type repeatStringTooLargeError struct {
+	s string
+	n float64
+}
+
+func (err *repeatStringTooLargeError) Error() string {
+	return "repeat string result too large: " + Preview(err.s) + " * " + Preview(err.n)
+}
+
 type objectKeyNotStringError struct {
 	v any
 }

operator.go

@@ -433,12 +433,15 @@ func deepMergeObjects(l, r map[string]any) any {
 }
 
 func repeatString(s string, n float64) any {
-	if n < 0.0 || len(s) > 0 && n > float64(0x10000000/len(s)) || math.IsNaN(n) {
+	if n < 0.0 || math.IsNaN(n) {
 		return nil
 	}
 	if s == "" {
 		return ""
 	}
+	if n >= float64(math.MaxInt32/len(s)) {
+		return &repeatStringTooLargeError{s, n}
+	}
 	return strings.Repeat(s, int(n))
 }