fix(core): Duration.parse() doesn't parse milliseconds (#25010)

Added millisecond parsing to [Duration](https://github.com/aws/aws-cdk/blob/main/packages/aws-cdk-lib/core/lib/duration.ts).
`Duration.parse('PT0.005S').toMilliseconds()` is now correctly resolved to `5`.

Closes #24971.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/aws-cdk-lib/core/lib/duration.ts

@@ -67,16 +67,18 @@ export class Duration {
    * @returns the parsed `Duration`.
    */
   public static parse(duration: string): Duration {
-    const matches = duration.match(/^P(?:(\d+)D)?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?)?$/);
+    const matches = duration.match(/^P(?:(\d+)D)?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)\.?(\d{1,3})?S)?)?$/);
     if (!matches) {
       throw new Error(`Not a valid ISO duration: ${duration}`);
     }
-    const [, days, hours, minutes, seconds] = matches;
-    if (!days && !hours && !minutes && !seconds) {
+    const [, days, hours, minutes, seconds, milliseconds] = matches;
+    if (!days && !hours && !minutes && !seconds && !milliseconds) {
       throw new Error(`Not a valid ISO duration: ${duration}`);
     }
+    const millis = milliseconds ? milliseconds.padEnd(3, '0') : '';
     return Duration.millis(
-      _toInt(seconds) * TimeUnit.Seconds.inMillis
+      _toInt(millis)
+      + _toInt(seconds) * TimeUnit.Seconds.inMillis
       + (_toInt(minutes) * TimeUnit.Minutes.inMillis)
       + (_toInt(hours) * TimeUnit.Hours.inMillis)
       + (_toInt(days) * TimeUnit.Days.inMillis),
@@ -251,8 +253,8 @@ export class Duration {
       }
     }
 
-    // Remainder in millis
-    if (millis > 0) {
+    // Remainder in millis (keep only above threshold)
+    if (millis > 0.0001) {
       ret.push([millis, TimeUnit.Milliseconds]);
     }
     return ret;

packages/aws-cdk-lib/core/test/duration.test.ts

@@ -98,20 +98,25 @@ describe('duration', () => {
 
     expect(Duration.seconds(65).toIsoString()).toEqual('PT1M5S');
     expect(Duration.seconds(1 + 60 * (1 + 60 * (1 + 24))).toIsoString()).toEqual('P1DT1H1M1S');
+    expect(Duration.millis(1 + (1000 * (1 + 60 * (1 + 60 * (1 + 24))))).toIsoString()).toEqual('P1DT1H1M1.001S');
   });
 
   test('parse', () => {
+    expect(Duration.parse('PT0.000S').toMilliseconds()).toEqual(0);
     expect(Duration.parse('PT0S').toSeconds()).toEqual(0);
     expect(Duration.parse('PT0M').toSeconds()).toEqual(0);
     expect(Duration.parse('PT0H').toSeconds()).toEqual(0);
     expect(Duration.parse('P0D').toSeconds()).toEqual(0);
 
+    expect(Duration.parse('PT0.005S').toMilliseconds()).toEqual(5);
+    expect(Duration.parse('PT0.5S').toMilliseconds()).toEqual(500);
     expect(Duration.parse('PT5S').toSeconds()).toEqual(5);
     expect(Duration.parse('PT5M').toSeconds()).toEqual(300);
     expect(Duration.parse('PT5H').toSeconds()).toEqual(18_000);
     expect(Duration.parse('P5D').toSeconds()).toEqual(432_000);
 
     expect(Duration.parse('P1DT1H1M1S').toSeconds()).toEqual(1 + 60 * (1 + 60 * (1 + 24)));
+    expect(Duration.parse('P1DT1H1M1.001S').toMilliseconds()).toEqual(1 + (1000 * (1 + 60 * (1 + 60 * (1 + 24)))));
   });
 
   test('reject illegal parses', () => {