Random jumps on topic load



  • This is frustratingly unpredictable, but from time to time, when clicking a topic title on the main page, the topic will load to the post to be read, then blink out and display a post further up the page (maybe 20 or more posts away). Occasionally, it then blinks out again and redisplays the correct post, but generally it stays in the wrong place.

    It's annoying because it's hard to get back to the relevant post without scrolling until I find it. End doesn't solve it because there may be 50 unread posts.

    A similar bug is when clicking the header from the bottom of a topic page to take me back to the main list. In this case, instead of going to the top, it shows the bottom of the list, then loads more topics.

    I've noticed this on Chrome on both Linux and Windows, and far more frequently on my WP8 phone (IE10).

    I think what's happening in the first case might be:

    1. The user, scrolled to the top of the main topic list, clicks a topic.
    2. Discourse loads the content into the same page.
    3. Discourse registers that the scrollbar is at the top of the page, then loads previous content.
    4. Discourse attempts to scroll to the post you were intending to view.

    Where the result is dependent upon the order that steps 3 and 4 happen.

    I think there might be some race condition, which is handling infinite scroll requests, page content loading and scrolling to posts inconsistently.

    Is anyone else experiencing this, or is it just me on my desktop, a laptop and my mobile‽

    EDIT:
    On a related note, why can't we just use regular page requests when moving between different posts and the main topic list? The site seems very unresponsive while waiting on AJAX request because there's too little feedback. My browser gives me inbuilt feedback on regular page loads. This would also avoid a lot of potential scrolling issues.


  • Banned

    @Keith said:

    far more frequently on my WP8 phone (IE10).

    There are known bugs in IE10 mobile that cause positioning not to work at all. As in, you will always enter at the top of the topic regardless of read position. We're hoping IE11 mobile resolves this, since everything works fine on desktop IE10+IE11.



  • @codinghorror said:

    There are known bugs in IE10 mobile that cause positioning not to work at all.

    Okay. The problem does still occur in Chrome though, just less frequently.


  • Banned

    Do you have any extensions active in Chrome?



  • Nope.

    I've only noticed it happening when there are new posts to read. I can't seem to make it happen by just clicking on a long topic which I've already read. I'll keep trying though 😉

    EDIT:
    It'll be most telling to see if other people have experienced it. Again, I've had it happen on two different computers with different operating systems, so I find it hard to believe I'm the only person affected.



  • It just happened on the thread FAQ Requests.

    I refreshed the front page. Clicked that topic, which was now at the top of the list and had a single outstanding reply. The topic loaded to the new reply, quickly blinked out to white and loaded back in at the very top of the post.

    There were only 14 posts, so it's not specific to long topics.


  • Banned

    I wonder if having the "system alert" header in is affecting this, since that seems to load before the rest of the page. Did you see this happen at all before the "system alert" about the Paula Bean bot was added?



  • It's been happening since I first used the forum. I ignored it as a teething problem at first and because I figured it would be almost impossible to debug. There were so many other issues that it seemed probable that one of the other fixes would indirectly fix this.

    I'll put a reply in here every time it happens with the steps that lead to it.


  • Banned

    I agree, I experience this jumpiness on mobile sometimes, its something about our render pipeline, I am investigating.



  • Just happened again on this topic (very meta).

    This time, I loaded the site, clicked the speech bubble and clicked the outstanding notification (your post, @sam). Your post loaded briefly, blinked out, then I was back at the very top of the topic.



  • Same again on FAQ Requests after a refresh on the main list, then clicking on the topic name. Topic loaded to the new post (with a blue tint), then jumped up to the top.

    Shall I stop reporting these now?



  • I got this with a smooth scrolling extension in chrome; you said you are not running an extension in chrome, but are you running some manufacturer programs that do the same? I know logitech likes to bundle that crap into an always running service for some damn reason - I hate having extra programs in my tray for things like mice mouses common hardware.



  • I do indeed have a Logitech mouse, but there's nothing in the tray and I can't find any processes or services relating to the company.

    Also, the browser definitely doesn't scroll smoothly, it jumps about 5 lines with each scroll click.



  • @DrakeSmith said:

    [s]mice mouses[/s]

    Meese.



  • One last report!

    This link: http://what.thedailywtf.com/t/poll-how-do-you-feel-about-discourse-on-tdwtf/761/99

    Loaded, then jumped me to the position indicated in this screen grab:



  • @Keith said:

    A similar bug is when clicking the header from the bottom of a topic page to take me back to the main list. In this case, instead of going to the top, it shows the bottom of the list, then loads more topics.

    I see this when using the back button to return to the topic list.

    @codinghorror said:

    Did you see this happen at all before the "system alert" about the Paula Bean bot was added?

    Yes, but it seems to be more frequent now. No data to confirm that, though.


  • Banned

    @Keith said:

    A similar bug is when clicking the header from the bottom of a topic page to take me back to the main list. In this case, instead of going to the top, it shows the bottom of the list, then loads more topics.

    I can't quite parse what you mean here, but if you return to a topic list from a topic, we attempt to take you to your last position in that topic list. Here is what I mean.

    1. Open homepage
    2. Scroll down a bit (trigger loading)
    3. Click any random topic
    4. Click the back button

    You should now see the topic you just clicked highlighted in the list and fade. So we also try to preserve position in the list, otherwise we can't highlight and fade your previous place in the topic list.



  • @codinghorror said:

    if you return to a topic list from a topic, we attempt to take you to your last position in that topic list.

    @codinghorror said:

    You should now see the topic you just clicked
    The problem is that the attempt sometimes fails, and what we actually see is not what we should see. Rather, occasionally we are positioned at some apparently random point in the topic list.

    I think what @Keith was saying is that, instead showing the last clicked topic (I'm assuming Keith is fairly up-to-date in his reading, so this is on the first screen-full of topics, and this is what he means by "the top"), it shows the last topic in the list that was loaded, which triggers loading more. I have definitely seen this, but more often I just see some random screen-full of topics. Could be that it's really the same, but most of the time the loading happens too quickly to notice.



  • @HardwareGeek has hit the snail on the head.

    Filed under: 🐌




  • :belt_onion:

    @HardwareGeek said:

    Filed under: Get off my lawn... er, garden!

    Necroed via Suggested Topics.

    Bug Report: Suggested Topics should be renamed Suggested Topics and some random Topics to Necro.


  • SockDev

    How about simply: "Random shit you might care about"


  • Banned

    I know you guys are joking but we started with "the dumbest backfill that can work" (after new, unread, and stuff you own) and I have been consistently surprised how well choosing random non closed topics within the current category works.

    YMMV of course, but random worked better for me than I ever thought possible.


  • SockDev

    You mean it actually was random as opposed to picking any other criteria you could choose from?


  • BINNED

    @codinghorror said:

    YMMV of course, but random worked consistently better for me than I ever thought possible.

    Ok Swampy, we're on to you now, you can come out.



  • @Arantor said:

    Random shit you might care about

    Emphasis on "might."


  • SockDev

    Followed by emphasis on 'random' because it actually is random.



  • @codinghorror, @sam, the problem from the OP is still happening quite regularly. I'm starting to think it's only for me though as nobody else seems to have mentioned it.


    Filed under: Sorry for the on-topic post, it won't happen again.



  • @Keith said:

    I'm starting to think it's only for me though as nobody else seems to have mentioned it.

    It's definitely not just you. It's happening to me, too, on maybe 10% (ass-pull) of topic loads. Annoying as all-get-out.



  • I tend to see it only in mobile view on a mobile device, but I do see it now and again.



  • This only happens to me if I scroll up enough that discourse decides it should load the previous set of comments (which, on a short post, that's not very much scrolling)

    I really don't like that the initial posts aren't loaded (at least progressively) when you jump to a point inside a topic, it's extremely disorienting to jump in to a topic from another link, scroll up to figure wtf people are talking about, and have the forum jitter all over the place.



  • I'm seeing this happen not only on initial load, but when Discurse decides to update something somewhere in the DOM. I may be reading the last, or close to last, post in the topic, when things start jumping around, and all of a sudden I'm looking at post[Math.random()].



  • @HardwareGeek said:

    when Discurse decides to update something somewhere in the DOM

    I've had it jump when loading more posts below, although not normally very far.



  • @Keith said:

    I've had it jump when loading more posts below

    Yeah, that wouldn't surprise me too much, but I've had it jump to post #1, gone back to the bottom, and there were no new posts. I'm not sure what got updated.



  • @codinghorror said:

    1. Open homepage

    1. Scroll down a bit (trigger loading)
    2. Click any random topic
    3. Click the back button
    1. Click the forward button
    2. Click the back button
    3. goto 5

    When I do this, first the old page scrolls, then the new page loads.


  • :belt_onion:



  • Yesterday I was seeing one or two topics — rather long ones, but not the "Likes" thread — where the document "vibrated" up and down by a few pixels for a second or two on load. I don't know if it still doing it; I haven't gotten to those topics yet this morning. Since it just started, I suspect it might have something to do with the new spoiler formatting, but that's just a wild guess.

    Edit: Just did it in Feature Request: Pending responses indicator, and that has no spoilers, so that's not the cause.



  • @fatbull said:

    5. Click the forward button

    1. Click the back button
    2. goto 5

    When I do this, first the old page scrolls, then the new page loads.

    So does here, but I can't tell you about that because the loop has no terminating condition.


    Filed under: i've been doing it for 40 minutes now, somebody help

    (edit: wtf, it not only doesn't quote the numbers, but won't even let you add them yourself the right way?!)



  • @Maciejasjmj said:

    1. Click the forward button

    1. Click the back button
    2. goto 5

    @Maciejasjmj said:

    So does here, but I can't tell you about that because the loop has no terminating condition.

    I tried it, but I got an index out of bounds exception :(.



  • @Keith said:

    I tried it, but I got an index out of bounds exception .

    Thanks Obama@codinghorror!


    Filed under: also: @mentions right next to > work, but don't unroll the list



  • @Keith said:

    This is frustratingly unpredictable, but from time to time, when clicking a topic title on the main page, the topic will load to the post to be read, then blink out and display a post further up the page (maybe 20 or more posts away). Occasionally, it then blinks out again and redisplays the correct post, but generally it stays in the wrong place.

    Bump. I've seen this, or something similar, discussed more recently, but I can't find it, and DiscoSearch found this one. So necro.

    I'm still seeing this, even more frequently than I used to, and I don't see anything here to indicate it's been fixed (or even "fixed"). It's really annoying.

    I also have some new information that might be relevant. It is now fairly consistently jumping backwards by ~50 posts (±~10). @Keith said it used to jump by ~20. @PJH somewhat recently increased the size of the chunk of posts that gets loaded from 20 to 50.

    I think it may have something to do with a new post arriving in another topic (which happens frequently), and Dicsores updating the Suggested Topics at the same time it's trying to load the posts in the current topic. However, that is only a WAG, based in part on something that was said in the other topic I can't find.


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