small fixes

packages/replay/src/replay.ts

@@ -400,7 +400,7 @@ export class ReplayContainer implements ReplayContainerInterface {
     this.recordingMode = 'session';
 
     if (this.session) {
-      this._updateSessionActivity(activityTime);
+      this.session.lastActivity = activityTime;
       this.session.started = activityTime;
       this._maybeSaveSession();
     }
@@ -539,7 +539,7 @@ export class ReplayContainer implements ReplayContainerInterface {
 
   /**
    * Check the state/expiration of the session.
-   * The callback is used when the session is neither paused nor expired.
+   * The callback is called when the session is neither paused nor expired.
    */
   public checkSessionState(onContinue: () => void): void {
     if (!this.session || !this.session.sampled) {
@@ -610,7 +610,7 @@ export class ReplayContainer implements ReplayContainerInterface {
 
     // this method is generally called on page load or manually - in both cases
     // we should treat it as an activity
-    this._updateSessionActivity();
+    this.updateUserActivity();
 
     this.eventBuffer = createEventBuffer({
       useCompression: this._options.useCompression,

packages/replay/src/util/sampleSession.ts

@@ -19,5 +19,5 @@ export function sampleSession({
     return 'session';
   }
 
-  return 'buffer';
+  return errorSampleRate > 0 ? 'buffer' : false;
 }

packages/replay/test/unit/util/sampleSession.test.ts

@@ -0,0 +1,28 @@
+import type { Sampled } from '../../../src/types';
+import { sampleSession } from '../../../src/util/sampleSession';
+
+// Note: We "fix" Math.random() to always return 0.2
+const cases: [number, number, Sampled][] = [
+  [0, 0, false],
+  [-1, -1, false],
+  [1, 0, 'session'],
+  [0, 1, 'buffer'],
+  [0.1, 0.1, 'buffer'],
+  [0.1, 0, false],
+  [0.3, 0.1, 'session'],
+  [0.3, 0, 'session'],
+];
+
+describe('Unit | util | sampleSession', () => {
+  const mockRandom = jest.spyOn(Math, 'random');
+
+  test.each(cases)(
+    'given sessionSampleRate=%p and errorSampleRate=%p, result should be %p',
+    (sessionSampleRate: number, errorSampleRate: number, expectedResult: Sampled) => {
+      mockRandom.mockImplementationOnce(() => 0.2);
+
+      const result = sampleSession({ sessionSampleRate, errorSampleRate });
+      expect(result).toEqual(expectedResult);
+    },
+  );
+});