v20.9.3 hogs system resources #3527

Thanks for the detailed report, but does this happen on any page? If not, please leave a link where it happens.

There have been some changes lately that might cause this, but we had just hoped they wouldn't — #3084

Also, can you try finding which version started causing this? https://addons.mozilla.org/en-US/firefox/addon/refined-github-/versions/

Also, more helpfully, can you try clicking on "Debug script" to see where it stops? This might take a minute to stop, but it will provide information about what's causing it.

Same issue here on ArchLinux, FF 80.0.1 Actually as soon as I interact with the yellow bar, either to disable the addon on the page, stop the script or debug the whole Firefox UI stops responding and only solution is to kill Firefox. I'll have to disable the extension for the time being. I think the issue might have caused by the 20.9.3 update. Before this update everything was working perfectly on my side.

If there's any other way to give helpful information I'd be happy to provide them.

Same here on OSX Catalina, Firefox 81.0b4, Refined Github 20.9.3, on any github repo. I hit debug but no luck, the page just hangs.

Same problem, it only occured on repository page. I'm using version 20.9.3 on Chrome 85.0.4183.83

Looking at the dev console, the problem is because this line of code https://github.com/sindresorhus/refined-github/blob/master/source/features/cleanup-repo-filelist-actions.tsx#L38

refined-github.js:9621 Uncaught TypeError: Cannot read property 'nextSibling' of null

Line 9621 on the packaged(?) script

        Object(select_dom["a"])(".octicon-download", downloadButton).nextSibling.remove();

That would probably explain why this 'hang' happens only on the "Code" tab and doesn't happen on "Issues" or "Pull requests" tabs.

I was looking at the changes that went into this release - it wasn't much but I found #3517 and somehow felt that the observe block and the onetime(init) could be the source of the problem; though I couldn't connect it to the selector-observer and https://bugzil.la/1422522

I just tried to reproduce I did a fresh install (brand new computer) and I am not seeing the issue. Note I am on windows.

@noaione I dont see the error. Do you have some kind of feature preview enabled? Or exact steps you are doing?

@yakov116 in my testing, I created a new Firefox profile to simulate a fresh install. The only extension I installed on the profile was the latest release of refined github. In fact, that was the only thing I did on that profile - my Steps to Reproduce in the description of the bug report describes it.

I opened the new profile, installed the Refined Github extension, and the install opens the Refined Github updates issue with no problem. Then I click on the Code tab on the page and the page almost loads completely before the warning is shown by the browser that the extension is slowing the page down. Then it goes on a resource hog.

@shinenelson can you try to back version to see if that helps?

like user njibhu commented, this started happening after the latest update. I had the extension enabled until then and it was working fine.

and like fregante commented, this was caused due to the change in #3517 with selector-observer which went into this latest release. Though the Firefox bug report that I had linked to in a previous comment ( which was sourceed from 3084 ) was RESOLVED FIXED 2 years ago, the issue could also come back again now.

I understand and would like to attempt to debug it. Are you able to load a previous version of refined-github to see if that fixes the issue

I thought it was obvious from mine as well as njibhu's comments that previous versions would work fine until this latest release. I will still do a test for you on a fresh profile with the last version.

Can you see if it freezes when you go to https://github.com/sindresorhus/refined-github/branches? Select-observer is used there too (and many other pages implemented about a month ago)

Does disabling cleanup-repo-filelist-actions fix it?

Are you able to load a previous version of refined-github to see if that fixes the issue

Yes, it does. I rolled back to extension version 20.8.30 ( of course on a fresh new profile ) and could not reproduce the issue. This is not really a fix or a solution. It is only validating that the latest version is the offending version.

Can you see if it freezes when you go to https://github.com/sindresorhus/refined-github/branches?

No, it does not. As (re-)confirmed with the test with the previous version, the offending feature is in this latest release.

Does disabling cleanup-repo-filelist-actions fix it?

Yes, it does!

thinks to self : " why did you have to disable the whole extension for one offending feature? why didn't you think of disabling the offending feature yourself? " :facepalm:

disabling the cleanup-repo-filelist-actions feature is a good workaround to this current problem rather than having to disable the whole extension. I don't want to miss out on the many features that the extension already provides because of one feature that kind of went rogue.

✅

I'm publishing 20.9.4 for the time being, reverting https://github.com/sindresorhus/refined-github/pull/3517

Can you provide exact URLs where this happen? Does this happen on https://github.com/sindresorhus/refined-github?

Are you guys on Enterprise?

Are you guys on Enterprise?

nope.

btw, I feel like there is an infinite loop somewhere. I'm pretty sure it's not connected to the fact observers' performance are not super.

It happens on https://github.com/tituspijean/docs.contribute for me (and other pages too).

noaione's https://github.com/sindresorhus/refined-github/issues/3527#issuecomment-687079196 indicate that it should be on every page that has the .octicon-download class which would mean <repo-url>/tree/* where the download button that uses https://download-directory.github.io is present.

Are you guys on Enterprise?

not me.

the download button that uses download-directory.github.io is present

That button isn't affected, the selector is very specifically get-repo details which only appears on the root (get-repo being the custom dropdown element with the "clone/download" links)

Aaaaannd I can't reproduce any more. I'm pretty sure it's an interaction with another addon, possibly octotree, because disabling and enabling it made the problem go away for me.

@autra : can you check whether your add-on got updated to v20.9.4? it was published a little earlier reverting #3517.

@autra I have Octotree as well and cannot reproduce (on Chrome 86.0.4240.22, though I believe this doesn't affect Chrome) @fregante I can reproduce it on Firefox 80 with a fresh install

That button isn't affected, the selector is very specifically get-repo details which only appears on the root (get-repo being the custom dropdown element with the "clone/download" links)

@fregante is right. that was the change in #3517. my bad :pray:

so, all the root repository pages then? I think I had it reproduce on josh/selector-observer too during my initial hangs and tests ( before I went hard-core debugging the issue )

The error in https://github.com/sindresorhus/refined-github/issues/3527#issuecomment-687079196 suggests that get-repo details .octicon-download doesn't exist. That's really strange because we don't remove it.

I made it crash by doing this in the console:

1. Remove download icon
2. Rename details tag to whatever
3. Rename it back to details, it immediately hangs

So indeed this loops inside the add function, probably because of the error. This is kinda of a new problem with selector-observer; if that happens every time GitHub changes the DOM we're screwed.

My guess: https://github.com/josh/selector-observer/issues/30

I don't know if this will be of much help

The .octicon-download button is there though.

This is really strange, I can reproduce it when I didn't login into GitHub, but cannot when I logged in (both without setting token, Firefox 80)

@fregante Maybe just

- select('.octicon-download', downloadButton)!.nextSibling!.remove();
+ select('.octicon-download', downloadButton)?.nextSibling!.remove();

Or the good old way:

-    observe('get-repo details', {
+    observe('get-repo details:not(.rgh-cleanup-repo-filelist-actions)', {
        add(downloadButton) {
-            downloadButton.classList.add('tooltipped', 'tooltipped-ne');
+            downloadButton.classList.add('tooltipped', 'tooltipped-ne', 'rgh-cleanup-repo-filelist-actions');

Maybe just

- select('.octicon-download', downloadButton)!.nextSibling!.remove();
+ select('.octicon-download', downloadButton)?.nextSibling!.remove();

That just hides the error, we don't do that. We can however change the original selector to point directly to the SVG, which would fix this specific issue for the time being.

My guess is that we add the classes, triggering a new MutationEvent, but selector-observer doesn't get to deduplicate it because add throws an error.

I tried to only remove the last line (select('.octicon-download', downloadButton)!.nextSibling!.remove()) and it didn't stuck

And when I printed a message in the function:

@autra : can you check whether your add-on got updated to v20.9.4? it was published a little earlier reverting #3517.

I'm still on v20.9.3

@kidonng probably just observe the download button directly:

observe('get-repo details .octicon-download', {............})