Re-reviewed A Word by Hitting 'Back' Button on Browser


#1

Using Chrome Browser.

I was doing an infinite review of 122 words in my pool using text-input.

At the end of my review, the blue review button for 122 words popped up again. I ignored it, suspecting it to be a bug and went to my dashboard. True enough, I didn’t have another 122 words to review. To see if I could go back to the screen suggesting I continue reviewing 122 more words, I hit ‘back’ on my browser.

It returned me to the final sentence I had finished reviewing… except it allowed me to review it again (I went from 0% to 25% in my initial review and then re-reviewed it to 50% within a couple of seconds). I input the correct answer, bumping my score up again and it sent me to the next sentence in that previous infinite review session. I imagine I could have re-reviewed that session as many times as I wanted to.

I hit the dashboard button again. I tried to hit ‘back’ to see if I could replicate it… but now the infinite session won’t load (which is a great thing).

But I’m worried this can be exploited. The next time I have an infinite review session, I will see if I can intentionally exploit it to mastery (not for points-sake, but to see if the bug is repeatable).


#2

I reviewed like 360 words today and failed to leave a word to test this review theory on. I’ll keep trying.

But I did verify the exploit exists for new words. I did a new words session using text input with 5 sentences per round.

After learning those 5 words for the first time, I was awarded 40 points as usual (8 pts x 5 words).

I then would click the dashboard button. Once on the dashboard, I hit ‘back’ on my browser. This returned me to that same 5 word learning session but the mastery still only reflected 0%. I completed the session again, returning it to 25% mastery, the session told me I earned 40 points as usual.

However, upon return to the dashboard I was awarded 80 points (16 points x 5), which would reflect as if I had reviewed those words from 25% to 50%.

I repeated the process. Again, it reflected 0% mastery initially but upon return to the dashboard I was awarded another 120 points (24 points x 5).

I repeated the process again and was awarded 160 points (32 points x 5).

Interestingly, every session onward reflected only 20 points (4 points x 5) for those words which is like doing multiple choice on 0% words.

Essentially, within a couple minutes I gathered 400 points. If someone were desperate for points, they would just mine new words until they start yielding low points and move onto the next set of words to repeat the process.


#3

Thanks for the detailed bug report! This is really helpful. Seems like your browser might be caching the page which is why you’re able to see the same sentences when hitting the back button. We’ll have to come up with some way to prevent the caching and/or force new words.

We do restrict the number of points scored for sentences played before they’re ready for review (which is why you’re only getting 4 points per answer regardless of % Mastered). I suppose we could try restricting points/progress for sentences not yet ready for review unless there are no new sentences left, but I’ll have to give it some more thought, and it may not be necessary if we’re able to come up with a different/better fix.

I’ve added this issue to queue. Thanks again!