The previous batch of improvements to this code path in
6562ea94e4 introduced a race bug where:
- You navigate to a narrowed view; Zulip renders cached data from
`all_messages_data` that we know is current, but
`fetch_status.has_found_newest` is initialized to `false`
nonetheless.
- The bottom is visible, triggering the check for whether the view
should be marked as read.
- `fetch_status.has_found_newest` is still `false`, and so we
incorrectly refuse to mark as read.
- We finish fetching data from the server, do the background rerender
for that (with no changes), but that doesn't trigger a re-check for
whether the bottom is visible.
There's several ways to address this, but most correct to me is to not
check fetch_status in this particular code path.
The same reasoning applies to the navigate.js call sites.
I was not able to reproduce obviously badly broken behavior from these
logic bugs, but after the renaming of message_viewport helpers in the
last few commits, it's clear that this logic was trying to check if
we're actually at the start/end of the possibly message feed, not just
the rendered portion, and doing so incorrectly.
Some files already were using `noop` in place of `() => {}`.
It's both clearer what it means and is easier to type.
This updates all test files to fully use `noop`, and
adds a shared import from the test lib file.
Since is_visible was refactored to use a variable, these mocks
are not required.
Also, since is_visible return `false` by default, mocking it
to return false is not required.
This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Tim Abbott
Evy Kassirer
Anders Kaseorg
Aman Agrawal
evykassirer