Duplicates appearing in HN top?
Hi,
I'm noticing duplicates appear on the top list of HN. I've got a screenshot if people need one but thought I'd post this in case someone who can fix this views 'new' postings.
I'm noticing duplicates appear on the top list of HN. I've got a screenshot if people need one but thought I'd post this in case someone who can fix this views 'new' postings.
1. Back out latest release, which contained a bunch of low-level changes, and restart the server.
2. Use the server repl to analyze what's happening. Notice that the problem is duplication in the list of top stories, because its len is 180 and len:dedup of it is 157. Fix the immediate problem with
(zap dedup ranked-stories*)
2. The list of top stories is kept in order by reinserting things into it when they get upvoted. Hypothesis: this code is not recognizing duplicates.
3. Here's the operator that does that:
(def reinsert-sorted (test elt seq)
(if (no seq)
(list elt)
(is elt (car seq))
(reinsert-sorted test elt (cdr seq))
(test elt (car seq))
(cons elt (rem elt seq))
(cons (car seq) (reinsert-sorted test elt (cdr seq)))))
(rem elt seq)
(def testify (x)
(if (isa x 'fn) x [is _ x]))
(def testify (x)
(if (in (type x) 'fn 'table) x [is _ x]))
6. Revert to old definition of testify, test on localhost, commit code, restart server again.
7. Be really thankful that the problem was not some other much more frightening stuff we changed today, like the definition of atomic.