The previous commit introduced a bug where it was not intuitive
for the user to scroll again.
For the current narrow, new messages were fetched again only when
scrolled to the bottom as usually there are many messages displayed.
However when the edge case mentioned in the previous commit
occured, it was not very obvious that a scroll should be done
or we could already be at the bottom and could not scroll again
to trigger a fetch.
`message_viewport.at_bottom` has a relevant comment explaining
this behaviour.
The previous commit handled the rare race condition. However,
there is a possibility that the rare race condition might occur
again while we are handling the previous condition.
This commit resolves these 2 problems by performing a re-fetch
while also resetting the `expected_max_message_id` and this
approach has two benefits:
1. The reset prevents an infinite loop, if somehow the expected
max message's id gets corrupted resulting in a situation
where the server can never send an id greater than that even
after fetching.
2. Even though we stop after just one re-fetch the race condition
might recursively occur while we handle the previous race
condition. And even though the reset prevents multiple re-fetches,
we don't have the missing message problem.
This is because we treat the next race condition as a new race
condition instead of it being a continuation of the previous.
The `expected_max_message_id` gets updated again, on receiving
a new message. Thus it can again enter the `fetch_status` block
as the reset value is updated again.
If a user sends a message while the latest batch of
messages are being fetched, the new message recieved
from `server_events` gets displayed temporarily out of
order (just after the the current batch of messages)
for the current narrow.
We could just discard the new message events if we havent
recieved the last message i.e. when `found_newest` = False,
since we would recieve them on furthur fetching of that
narrow.
But this would create another bug where the new messages
sent while fetching the last batch of messages would not
get rendered. Because, `found_newest` = True and we would
no longer fetch messages for that narrow, thus the new
messages would not get fetched and are also discarded from
the events codepath.
Thus to resolve both these bugs we use the following approach:
* We do not add the new batch of messages for the current narrow
while `has_found_newest` = False.
* We store the latest message id which should be displayed at the
bottom of the narrow in `fetch_status`.
* Ideally `expected_max_message_id`'s value should be equal to the
last item's id in `MessageListData`.
* So the messages received while `has_found_newest` = False,
will be fetched later and also the `expected_max_message_id`
value gets updated.
* And after fetching the last batch where `has_found_newest` = True,
we would again fetch messages if the `expected_max_message_id` is
greater than the last message's id found on fetching by refusing to
update the server provided `has_found_newest` = True in `fetch_status`.
Another benefit of not discarding the events is that the
message gets processed not rendered i.e. we still get desktop
notifications and unread count updates.
Fixes#14017
This commit makes the `loading_older_messages_indicator` similar
to the `loading_newer_messages_indicator`.
Now all the decisions about whether to show a loading indicator
will be made from the `fetch_status` API. We still hide the
indicators everytime the view is changed, as explained in the
previous commit.
As explained in 67053ff479,
multiple message fetches may be taking place at the same time.
So some other narrows / the home message list's indicator might
get shown for the current narrow.
This commit moves the updation of the indicators display logic
to the `fetch_status` API.
Now the `loading_newer_messages_indicator` gets displayed along
with the `loading_newer` = true updation for that narrow's message
list, i.e. just before we send the API request. But only if the
message list we are fetching matches with our current message list.
The same indicator is hidden similarly, along with the
`loading_older` = false updation for that narrow's message list,
i.e. just after the success response is recieved. But only if
the message list whose data we recieved matches with our current
message list.
Also the indicators are hidden everytime we activate narrow
or deactivate narrow (`home_msg_list`). And on entering
`narrow.activate` we fetch for it's messages so they get
displayed again, if need be.
This is the reason `message_scroll.hide_indicators();` was
moved to a location above `fetch_messages`.
Fixes#15374.
The streams:all advertisement notice in search should only appear
after all results have been fetched to indicate we've gotten to the
beginning of the target feed.
The notice gets hidden at the start of `narrow.activate` and is
shown just after we've fetched an older batch of messages if the
"oldest" message has been found.
Previously it would get displayed after the first fetch which
takes place from `narrow.activate`. Thus we move this logic to
`notifications.hide_or_show_history_limit_message` which gets
called after a successful message fetch.
Since the home message view contains all the messages we are not
required to display this notice. However if it is already shown
we hide it as a part of `handle_post_narrow_deactivate_processes`.
To accomplish this we need to add `has_found_oldest` key to the
`fetch_status` API.
We also removed the `pre_scroll_cont` parameter as this was it's
only use case and is now redundant.
This commit was originally automatically generated using `tools/lint
--only=eslint --fix`. It was then modified by tabbott to contain only
changes to a set of files that are unlikely to result in significant
merge conflicts with any open pull request, excluding about 20 files.
His plan is to merge the remaining changes with more precise care,
potentially involving merging parts of conflicting pull requests
before running the `eslint --fix` operation.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
With webpack, variables declared in each file are already file-local
(Global variables need to be explicitly exported), so these IIFEs are
no longer needed.
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Like the other similar commits, we were doing the same work in all
code paths, just with a much more error-prone approach.
We can also now remove the now-unused finish_initial_narrow function.
Like the other commits in this series, we were already doing this in
all of the callers of load_messages; this centralizes that logic in a
less ad-hoc feeling way.
We no longer use or need the start_initial_narrow function.
Previously, each individual caller of load_messages that passed
num_before > 0 would do its own manual management of fetch_status;
now, we just do it inside load_messages.
This commit prepares the frontend code to be consumed by webpack.
It is a hack: In theory, modules should be declaring and importing the
modules they depend on and the globals they expose directly.
However, that requires significant per-module work, which we don't
really want to block moving our toolchain to webpack on.
So we expose the modules by setting window.varName = varName; as
needed in the js files.
This reverts commit bcdd12773e.
We need to do some improvements in handling FetchStatus for initial
narrows before this will be safe to deploy in production.
If individual messages arrive before we get the latest
messages from the server, they can create gaps in rendering,
and would often be offscreen anyway, so we just ignore them.
Ryan Rehman
Anders Kaseorg
Tim Abbott
Armaan Ahluwalia
Steve Howell