4.2.0: Minimal versions and breaking stuff #10047

sledgehammer999 · 2018-12-25T12:10:19Z

@qbittorrent/demigods
This thread will be used to discuss various things about 4.2.0 and list resolutions.

I think 2 agreed upon changes are going to c++14 and dropping Windows Vista and below support.

(can be edited by other team members)

List of resolutions:

Require at least c++14
Drop old migration/upgrade code
Drop Vista and XP support
Drop libtorrent 1.0 support
Raise requirement for libtorrent 1.1 to version 1.1.10
Support RC_1_2
Raise minimum Qt version to 5.9.0

sledgehammer999 · 2018-12-25T12:15:09Z

Qt 5.12 is LTS. We can stick to it in v4.2.x.

@glassez I don't think it is that simple. Ubuntu xenial (16.04) which is used in travis-ci uses Qt 5.5.1
IMO, we should raise the Qt requirement only if we want to make use of newer API.

A bit offtopic: On Windows, qbt with Qt 5.12 crashes sometimes during exit.
I also get 2 qt runtime warnings about requesting the same URL twice and about timers don't support stopping from different threads. Does anyone see any of that?

sledgehammer999 · 2018-12-25T12:16:08Z

I suppose I should add to the list:

Drop RC_1_0 support
Support RC_1_2 when it is released

right?

glassez · 2018-12-25T16:47:34Z

Ubuntu xenial (16.04) which is used in travis-ci uses Qt 5.5.1

Qt 5.5 is 3.5 years old. It's not supported now! Will Travis-CI tell us how to live?..
Even Qt 5.6 LTS is better option ("Since Qt 5.6" is very popular annotation in Qt documentation).

IMO, we should raise the Qt requirement only if we want to make use of newer API.

Personally, I feel uncomfortable without some of the improvements available in the new versions. I'm not calling to blindly jump to the latest Qt, but we should have reasonable progress here.

Drop RC_1_0 support

👍
But it's not enough. We should declare minimal supported version from 1.1.x branch.

Support RC_1_2 when it is released

👍
IMO, "when it is released" is redundant.

sledgehammer999 · 2018-12-25T17:19:22Z

Will Travis-CI tell us how to live?

So you wanna drop Continuous Integration?

We should declare minimal supported version from 1.1.x branch

Yes. We should require the latest release. IIRC 1.1.11

glassez · 2018-12-25T18:13:54Z

So you wanna drop Continuous Integration?

I can't insist on that...
I don't know much about TravisCI, but my quick search shows that other projects use newer Qt versions.

X-Coder264 · 2018-12-25T18:57:12Z

I don't think it is that simple. Ubuntu xenial (16.04) which is used in travis-ci uses Qt 5.5.1

You switched to Ubuntu Bionic (18.04) for Travis-CI two weeks ago. 18.04 comes with Qt 5.9 -> https://packages.ubuntu.com/bionic/libs/qt5-default / https://launchpad.net/ubuntu/bionic/+package/qt5-default

Isn't that available then on Travis too?

sledgehammer999 · 2018-12-25T22:56:26Z

@X-Coder264 nope. Travis-ci recently(less than a month) switched to xenial. I doubt it will also make available bionic.

Question is, is there anything from >5.5.1 that we need to make use of?

X-Coder264 · 2018-12-25T22:58:30Z

Oops, sorry, I must've seen something wrong :(

sledgehammer999 · 2018-12-25T23:01:15Z

If we actually need something from the newer Qt versions, then probably we can find a 3rd party PPA that provides new Qt5 for xenial/travis

X-Coder264 · 2018-12-25T23:05:21Z

@sledgehammer999 Yes, that would definitely be the best solution so that the old Qt version on Travis doesn't hold the project back. Here is for example the PPA for Qt 5.11.2 for Xenial -> https://launchpad.net/~beineri/+archive/ubuntu/opt-qt-5.11.2-xenial

Kolcha · 2018-12-26T07:06:49Z

Why don't build new Qt on Ubuntu xenial yourself? It is pretty easy, and you will get very minimal Qt (which contains only your required stuff). .tar.xz with such "hand-made" Qt will be ~20 MB and ~100MB unpacked, so this is not problem to download it on each build run + it is possible to configure travis to cache it. I can help with it, I did this on my own projects few times. and I pretty good know what qBittorrent uses from Qt, so it will not take a lot of time.

Chocobo1 · 2018-12-26T07:31:48Z

Even Qt 5.6 LTS is better option ("Since Qt 5.6" is very popular annotation in Qt documentation).

Yes, especially Qt 5.6 is LTS, we should at least try moving to it.

If we actually need something from the newer Qt versions, then probably we can find a 3rd party PPA that provides new Qt5 for xenial/travis

Agree.

Why don't build new Qt on Ubuntu xenial yourself?

I think we want as less burden on our shoulder as possible (the script is a bit messy already), I suppose if you create a separate PPA we can use it, or just packages in rpm format so we can fetch & install easily.

Another way of freeing ourselves from TravisCI OS limits is using docker images, but that would require rewriting the script & potentially slower build times, something I would not consider in near future unless necessary.

Kolcha · 2018-12-26T08:05:01Z

the script is a bit messy already

I mean don't build Qt each time on ci service, build it just once on local dev machine and just download it during build (like any other dependency, but manually, using well-known curl or wget, not through apt-get install). I don't think that these 2-3 lines in build script will make it so much complex and unreadable.

I suppose if you create a separate PPA

I'll try, I never did it, but I built deb packages. it will be interesting experience, but can't promise anything.

Chocobo1 · 2018-12-26T12:10:21Z

build it just once on local dev machine and just download it during build

Yes, that is what I meant about the rpm format (or deb), this is totally fine for me.

sledgehammer999 · 2018-12-26T15:19:19Z

Why into all this since there is already a 3rd party PPA for xenial with newer Qt?

PS: This will mean that we also drop ubuntu versions...

Chocobo1 · 2018-12-26T16:04:57Z

Why into all this since there is already a 3rd party PPA for xenial with newer Qt?

Is there one with Qt 5.6? We should have at least one linux CI build matching minimum requirements.

This will mean that we also drop ubuntu versions...

I'm having second thoughts... According to https://wiki.ubuntu.com/Releases , Ubuntu 16.04.5 LTS EOL is April 2021, damn long.

Chocobo1 · 2018-12-26T16:07:14Z

I also get 2 qt runtime warnings about requesting the same URL twice and about timers don't support stopping from different threads. Does anyone see any of that?

I did see the URL warning but not the other, can you file an issue so we can track it?

thalieht · 2018-12-26T16:49:53Z

and about timers don't support stopping from different threads.

That may be related to #10056 (and many other duplicates). I remember in that PR there was some talk about threads. But that can't be related to 5.12 because there are reports for it from a while back, since WebUI disk space was introduced in #8217.

glassez · 2018-12-26T17:03:24Z

PS: This will mean that we also drop ubuntu versions...

IMO, users of distributives that provide outdated and unsupported versions of libraries should be prepared to use outdated applications sooner or later...

glassez · 2019-01-02T05:42:55Z

@sledgehammer999, what is your final decision on minimal supported Qt version?

glassez · 2019-02-19T09:09:38Z

qBittorrent/src/app/application.cpp

Lines 653 to 677 in 78ab0e4

    
           void Application::shutdownCleanup(QSessionManager &manager) 
        
           { 
        
               Q_UNUSED(manager); 
        
               // This is only needed for a special case on Windows XP. 
        
               // (but is called for every Windows version) 
        
               // If a process takes too much time to exit during OS 
        
               // shutdown, the OS presents a dialog to the user. 
        
               // That dialog tells the user that qbt is blocking the 
        
               // shutdown, it shows a progress bar and it offers 
        
               // a "Terminate Now" button for the user. However, 
        
               // after the progress bar has reached 100% another button 
        
               // is offered to the user reading "Cancel". With this the 
        
               // user can cancel the **OS** shutdown. If we don't do 
        
               // the cleanup by handling the commitDataRequest() signal 
        
               // and the user clicks "Cancel", it will result in qbt being 
        
               // killed and the shutdown proceeding instead. Apparently 
        
               // aboutToQuit() is emitted too late in the shutdown process. 
        
               cleanup(); 
        
               // According to the qt docs we shouldn't call quit() inside a slot. 
        
               // aboutToQuit() is never emitted if the user hits "Cancel" in 
        
               // the above dialog. 
        
               QTimer::singleShot(0, qApp, &QCoreApplication::quit); 
        
           }

Is this stuff still needed after removing WinXP support?

sledgehammer999 · 2019-03-03T20:10:15Z

Is this stuff still needed after removing WinXP support?

Probably not.

To all: FYI, Qt version is proposed to be raised to 5.9.0 via PR #10338

glassez · 2019-03-21T08:07:22Z

I would like to be clear with libtorrent-1.2 support. Personally, I'm not suggesting having it as a v4.2.0 release goal, but to stretch its implementation and testing over the entire lifecycle of 4.2 branch (having libtorrent-1.1 as the main one).

sledgehammer999 · 2019-08-15T14:03:24Z

Did any of you guys test your regular qbittorrent profile with libtorrent 1.2.x?
I have build current master against 1.2.x in order to do an alpha release. I eventually run it on my normal profile. Almost everything seemed good (got crashes when quiting).
Then I opened my regular v4.1.7 install which uses libtorrent 1.1.x series. 17 completed torrents started rechecking. Not good. The log shows that the error is:

check resume(): missing or invalid 'file sizes' entry. Checking again...

I don't know if this is a fault of new torrent handling in qbt code or breaking changes in libtorrent.
Currently my torrents are still checking so I can't test further.

sledgehammer999 · 2019-08-15T14:06:35Z

I don't know if this is a fault of new torrent handling in qbt code or breaking changes in libtorrent.

One thing in common of those files: All of them were finished/compled but in the "Queued" status (aka not explicitly paused). I have set my max active uploads to zero so I don't upload anything. All finished torrents are Queued (to be seeded).
PS: I have others completed+paused which were not affected.

xavier2k6 · 2019-08-15T14:15:18Z

@sledgehammer999 I used the 4.2.0 build daily since it's release/last compiled version in #9120
Only switched back to 4.1.7 upon its release to see if silent crash was fixed as per #10581 & remained on that since I read there would be a public beta or alpha releasing soon.
QT 5.13/OpenSSL 1.1.1.c runs without any crashes/issues BTW.

Kolcha · 2019-08-15T14:15:26Z

@sledgehammer999 at least pieces field format changed in .fastresume, libtorrent 1.2 -> libtorrent 1.1 leads to re-hashing...
according to libtorrent docs, this is its change
new libtorrent can read old fastresume data, but saves in new format

Kolcha · 2019-08-15T14:19:05Z

QT 5.13/OpenSSL 1.1.1.c

👍 libtorrent 1.2, "hand-made" build for macOS, also no issues detected. but my seed box still running 4.1.7 with libtorrent 1.1

xavier2k6 · 2019-08-17T11:06:18Z

This should help performance wise if added & turned "ON"
arvidn/libtorrent#3913

sledgehammer999 · 2019-08-24T18:39:13Z

I just released an alpha1 build. It is based on libtorrent 1.1.x just to make sure that at least qbt code is stable. Then later releases will switch libtorrent 1.2.x series.
PS: Lib versions are the same as v4.1.7

glassez · 2019-08-24T19:00:33Z

Lib versions are the same as v4.1.7

👍
It's really good idea to never update all at once. We should release significant application changes with trusted library versions whenever possible. Otherwise it's really hard to catch the bugs.

Chocobo1 · 2019-08-25T15:11:12Z

@sledgehammer999
I tried the alpha build and I'm seeing silent crash events in Windows event viewer. None of them have stacktrace and all of them are 0xc0000005 (Access Violation) errors. The silent crash occurs after I hit exit in qbt.
Also I noticed you built it with Qt 5.13. That version isn't very stable for me, see issue #11117 and I would say you should stick to Qt 5.12.x series (it is LTS!) for stable releases.

~~I also build qbt with Qt 5.13 myself however I have no such crash from it, not sure why there is a problem from your build.~~ I'm seeing it now from my own build... no clue why.

xavier2k6 · 2019-08-25T16:21:29Z

Qt 5.13.0 requires OpenSSL 1.1.1 version on Linux and Windows
see: https://wiki.qt.io/Qt_5.13.0_Known_Issues

crash in 4.2.0 alpha1 issue experienced & logged
#11123

NOTE:

@sledgehammer999 I used the 4.2.0 build daily since it's release/last compiled version in #9120
Only switched back to 4.1.7 upon its release to see if silent crash was fixed as per #10581 & remained on that since I read there would be a public beta or alpha releasing soon.
QT 5.13/OpenSSL 1.1.1.c runs without any crashes/issues BTW.

glassez · 2019-08-25T16:28:21Z

you should stick to Qt 5.12.x series (it is LTS!) for stable releases.

👍

sledgehammer999 · 2019-08-25T18:32:25Z

Maybe on next release, I'll rebuild Qt using the 5.12.x series.

@Chocobo1 I too do get sometimes the crashes. I now have setup WinDbg as just-in-time debugger (or post-mortem debugger) to be used by Windows when it tells me that some program has crashed. Hopefully in the next crash, I'll be able to catch something relevant.

On a possibly related note: With master I always observe this console warning after I quit qbittorrent:

QObject::~QObject: Timers cannot be stopped from another thread

Do you guys know of a way to pinpoint from where this warning is coming? Or possibly how to a breakpoint on that?

Chocobo1 · 2019-08-26T06:38:06Z

Do you guys know of a way to pinpoint from where this warning is coming?

You could try setting QT_MESSAGE_PATTERN mentioned here: https://doc.qt.io/qt-5/debug.html#warning-and-debugging-messages

sledgehammer999 · 2019-08-26T13:46:07Z

@Chocobo1 I managed to catch a backtrace from the crash-on-exit. Here is the gist. (only the 1st thread seemed relevant)

xavier2k6 · 2019-08-26T14:38:04Z

@sledgehammer999 mentioned this in above post...you may have overlooked it...#11123

Chocobo1 · 2019-08-26T15:30:52Z

@Chocobo1 I managed to catch a backtrace from the crash-on-exit. Here is the gist. (only the 1st thread seemed relevant)

Looks similar with xavier2k6 dump. Unfortunately I couldn't make anything useful from it.

sledgehammer999 · 2019-08-26T15:58:07Z

This crash (and the timer warning I mentioned earlier) seems to happen only in master. So maybe just maybe this is related on how we refactored the exit code in master after the drop of the Windows XP-specific code? This is just a hypothesis.

About the timer warning: QObject classes have an internal timer associated with them. And this warning seems to be coming from the destructor of a QObject. So probably we are destroying a QObject (maybe one of our own custom subclass?) from the wrong thread. Related forum answer: https://forum.qt.io/post/271255

sledgehammer999 · 2019-08-28T21:40:16Z

I did a small discovery: The crashes and the timer warning seem to start with Qt 5.12.0+. The warning and the crash doesn't happen if I use Qt 5.11.3.
This is on Windows. On the linux side, I only dabble with debian, which is still at Qt 5.11 and I can't confirm the warning/crashes there.
Unfortunately, a small Qt "hello world" program, doesn't exhibit this behavior, so I can't file a bug report to Qt yet.

xavier2k6 · 2019-09-12T09:35:46Z

QObject::~QObject: Timers cannot be stopped from another thread

@sledgehammer999
Is issue still unresolved/present in Qt 5.13.1?

Use of SIGNALS & SLOT/Converting QTimer to pointer may help resolve issue/debug more.
https://stackoverflow.com/questions/26461887/qt-timers-cannot-be-stopped-from-another-thread
https://stackoverflow.com/questions/53288644/timers-cannot-be-stopped-from-another-thread-qt
therecipe/qt#341
https://www.oipapio.com/question-2554784

Or you have to run the GUI stuff in the main thread/try disabling the WITH_QT option in the make file.
https://discuss.haiku-os.org/t/qt5-error-qobject-timers-cannot-be-stopped-from-another-thread/7102

xavier2k6 · 2019-09-25T21:43:08Z

Latest libraries currently released/available.
Boost 1.71
OpenSSL 1.0.2t/OpenSSL 1.1.0l/OpenSSL 1.1.1d (security fixes)
Qt 5.13.1
Libtorrent 1.1.13/1.2.2

xavier2k6 · 2019-11-19T22:36:50Z

With Vista OS & below being dropped, how long until windows 7 support will be dropped as it's Microsoft support ends January 14th 2020?

Also what is the Minimum Windows 10 supported Build for Qbittorrent? - as some builds are now no longer supported by Microsoft.

sledgehammer999 · 2019-11-21T19:31:40Z

@xavier2k6 as long as msvc compilers still support targeting Windows 7, as long as Qt supports Windows 7, as long as there is significant user base using Windows 7 we won't drop it. Look at Windows XP, we haven't drop it yet. The drop will be with v4.2.0 final.
Why? We don't care about MS EOL dates. The Windows API is pretty stable between versions and it doesn't put undue burden on us to support in the codebase. Hell, we rarely have extra code for specific Windows' versions.

glassez · 2019-12-06T17:28:22Z

Shouldn't minimal supported versions be documented somewhere in project files?

sledgehammer999 added Discussion Project management labels Dec 25, 2018

sledgehammer999 added this to the 4.2.0 milestone Dec 25, 2018

sledgehammer999 mentioned this issue Jan 2, 2019

Drop upgrade code #10066

Merged

glassez mentioned this issue Jan 10, 2019

Drop support of libtorrent < 1.1.10 #10136

Merged

glassez pinned this issue Jan 12, 2019

glassez unpinned this issue Jan 12, 2019

thalieht referenced this issue Aug 25, 2019

Update Changelog

69f665e

xavier2k6 mentioned this issue Sep 25, 2019

Create Alpha/Beta/Release Candidate Labels for qBittorrent Issues Tracker #11220

Closed

xavier2k6 mentioned this issue Oct 27, 2019

Release plan for 4.2.0 final release #11280

Closed

sledgehammer999 closed this as completed Dec 3, 2019

xavier2k6 mentioned this issue May 7, 2020

qbt does not show the exact versions used to compile it #12774

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xavier2k6 mentioned this issue Sep 11, 2020

Drop 32-bit support #12417

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qbittorrent locked and limited conversation to collaborators Feb 25, 2021

4.2.0: Minimal versions and breaking stuff #10047

4.2.0: Minimal versions and breaking stuff #10047

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