fix(NODE-6144): Long.fromString incorrectly coerces valid inputs to L…

…ong.ZERO in special cases (#677)

src/long.ts

@@ -371,26 +371,58 @@ export class Long extends BSONValue {
 
   /**
    * Returns a signed Long representation of the given string, written using radix 10.
+   *
+   * If the input string is empty, this function will throw a BSONError.
+   *
+   * If input string does not have valid signed 64-bit Long representation, this method will return a coerced value:
+   * - inputs that overflow 64-bit signed long will be coerced to Long.MAX_VALUE and Long.MIN_VALUE respectively
+   * - 'NaN' or '+/-Infinity' are coerced to Long.ZERO
+   * - other invalid characters sequences have variable behavior
+   *
    * @param str - The textual representation of the Long
    * @returns The corresponding Long value
    */
   static fromString(str: string): Long;
   /**
-   * Returns a signed Long representation of the given string, written using radix 10.
+   * Returns a signed Long representation of the given string, written using the provided radix.
+   *
+   * If the input string is empty or a provided radix is not within (2-36), this function will throw a BSONError.
+   *
+   * If input parameters do not have valid signed 64-bit Long representation, this method will return a coerced value:
+   * - inputs that overflow 64-bit signed long will be coerced to Long.MAX_VALUE and Long.MIN_VALUE respectively
+   * - if the radix is less than 24, 'NaN' is coerced to Long.ZERO
+   * - if the radix is less than 35, '+/-Infinity' inputs are coerced to Long.ZERO
+   * - other invalid characters sequences have variable behavior
    * @param str - The textual representation of the Long
    * @param radix - The radix in which the text is written (2-36), defaults to 10
    * @returns The corresponding Long value
    */
   static fromString(str: string, radix?: number): Long;
   /**
    * Returns a Long representation of the given string, written using radix 10.
+   *
+   * If the input string is empty, this function will throw a BSONError.
+   *
+   * If input parameters do not have a valid 64-bit Long representation, this method will return a coerced value:
+   * - inputs that overflow 64-bit long will be coerced to max or min (if signed) values
+   * - if the radix is less than 24, 'NaN' is coerced to Long.ZERO
+   * - if the radix is less than 35, '+/-Infinity' inputs are coerced to Long.ZERO
+   * - other invalid characters sequences have variable behavior
    * @param str - The textual representation of the Long
    * @param unsigned - Whether unsigned or not, defaults to signed
    * @returns The corresponding Long value
    */
   static fromString(str: string, unsigned?: boolean): Long;
   /**
    * Returns a Long representation of the given string, written using the specified radix.
+   *
+   * If the input string is empty or a provided radix is not within (2-36), this function will throw a BSONError.
+   *
+   * If input parameters do not have a valid 64-bit Long representation, this method will return a coerced value:
+   * - inputs that overflow 64-bit long will be coerced to max or min (if signed) values
+   * - if the radix is less than 24, 'NaN' is coerced to Long.ZERO
+   * - if the radix is less than 35, '+/-Infinity' inputs are coerced to Long.ZERO
+   * - other invalid characters sequences have variable behavior
    * @param str - The textual representation of the Long
    * @param unsigned - Whether unsigned or not, defaults to signed
    * @param radix - The radix in which the text is written (2-36), defaults to 10
@@ -406,7 +438,11 @@ export class Long extends BSONValue {
       unsigned = !!unsignedOrRadix;
     }
     radix ??= 10;
-    if (str === 'NaN' || str === 'Infinity' || str === '+Infinity' || str === '-Infinity') {
+    if (str === 'NaN' && radix < 24) {
+      // radix does not support n, so coerce to zero
+      return Long.ZERO;
+    } else if ((str === 'Infinity' || str === '+Infinity' || str === '-Infinity') && radix < 35) {
+      // radix does not support y, so coerce to zero
       return Long.ZERO;
     }
     return Long._fromString(str, unsigned, radix);

test/node/long.test.ts

@@ -172,10 +172,14 @@ describe('Long', function () {
       radix: number | undefined,
       expectedStr?: string
     ][] = [
-      ['Infinity', 'Infinity', false, 34, '0'],
-      ['-Infinity', '-Infinity', false, 23, '0'],
-      ['+Infinity', '+Infinity', false, 12, '0'],
-      ['NaN', 'NaN', false, 16, '0']
+      ['radix 36 Infinity', 'Infinity', false, 36],
+      ['radix 36 -Infinity', '-Infinity', false, 36],
+      ['radix 36 +Infinity', '+Infinity', false, 36, 'infinity'],
+      ['radix < 35 Infinity', 'Infinity', false, 34, '0'],
+      ['radix < 35 -Infinity', '-Infinity', false, 23, '0'],
+      ['radix < 35 +Infinity', '+Infinity', false, 12, '0'],
+      ['radix < 24 NaN', 'NaN', false, 16, '0'],
+      ['radix > 24 NaN', 'NaN', false, 25]
     ];
 
     for (const [testName, str, unsigned, radix, expectedStr] of successInputs) {