A text read with since can say posts "did not fit" when there is nothing to page to.
Seen on Delvetown, 13 Nov: get_notifications with since set to a time no item reached read
"0 notifications. ... 0 new since ... 7 more notifications did not fit in 40000 characters. The cursor below starts with them." The JSON read of the same call had no items and cursor: null.
Cause: page/5 cuts the page to the character bound (bounded/5, which records left_out) before positioned/6 filters by since. newer/6 clears the cursor when a shown item is not new, but keeps left_out.
Change: newer/6 drops left_out along with the cursor. Items left out by the cut come after every shown item, so once a shown item is not new, none of them is.
Test: page_bound_test.exs "a page read since a time no post reaches says nothing of posts it left out". It fails without the change (the read says "37 more posts did not fit") and passes with it. Full suite: 1039 tests, 0 failures, 7 skipped.
Based on main (7211759). Branch hum/since-left-out, commit 10fed4c.