st 6. 1. 2021 v 19:10 odesílatel Adam Light <[email protected]> napsal:
> > > On Wed, Jan 6, 2021 at 3:15 AM Volker Hilsheimer <[email protected]> > wrote: > >> >> What can do better to avoid such regressions from making it into a >> release, or preferably into the code, in the first place? Nobody, not even >> the Qt Company management :P *wants* to release crappy quality on time. >> > > For major version releases, many of the regressions are intentional. For > example, going from Qt 4.8 -> 5, it was not until Qt 5.4 or 5.5 that we > could even compile our application on macOS and Windows without disabling > chunks of code due to missing features. Then we had to deal with all of the > subtle changes in how events were handled, some of which caused major > problems in our application. We finally shipped with Qt 5.6. It seems that > the Qt 6 cycle is starting out in a similar fashion, as Qt 6 won't be > feature complete until at least 6.2, so it's unlikely we will even think of > trying Qt 6 until then. Since we are still using 5.12 due to the lack of > LGPL LTS releases, if and when we ultimately move to Qt 6 there will be 2+ > years of changes that may cause problems with our application. That's on > top of any intentional deprecations and changes and figuring out how to get > our application to build with cmake (if that's necessary). > > For minor versions, I think most of the regressions are unintentional, but > it is not uncommon that we report a regression and it is simply ignored or > acknowledged but not fixed. Sometimes we can work around the regression in > our own code or by patching Qt ourselves. > > Here are some lists of issues, most of which we created, that may be > helpful to you in determining where the process broke down. > > Regressions that affected some version of 5.12 which have been fixed in > 5.12: > https://bugreports.qt.io/browse/QTBUG-77281 > https://bugreports.qt.io/browse/QTBUG-77255 > https://bugreports.qt.io/browse/QTBUG-74559 > https://bugreports.qt.io/browse/QTBUG-75825 > > https://bugreports.qt.io/browse/QTBUG-37804 is a regression from Qt > 4.8->5 that wasn't fixed until 5.15, and is still not fixed in 5.12 (as far > as I know). It sat as a P2 or P1 for over 6 years. > > Regressions in 5.12 that have not yet been fixed: > https://bugreports.qt.io/browse/QTBUG-72212 (5.9->5.12, still open) > https://bugreports.qt.io/browse/QTBUG-74530 (5.12.0->5.12.1, still open) > https://bugreports.qt.io/browse/QTBUG-89010 (5.12.9->5.12.10 I believe, > this causes a crash in our own fuzzing tests, so it's not a big deal but > unfortunate to see in a LTS and the change in behavior is undocumented) > https://bugreports.qt.io/browse/QTBUG-59805 (this is due to a macOS 10.11 > change but the Qt change needed to fix the regression and make captions > work as documented with native file dialogs is simple and documented in the > report) > https://bugreports.qt.io/browse/QTBUG-40895 (4.8->5.x regression (mac > only), closed as won't fix, we have no workaround but our customers haven't > complained so it's not too big of a problem for us) > > There are also advantages to LTS releases in that there are often fixes > for issues that appear in new macOS versions. A few examples: > > https://code.qt.io/cgit/qt/qtbase.git/commit/?h=5.12&id=c5d904639dbd690a36306e2b455610029704d821 > > https://code.qt.io/cgit/qt/qtbase.git/commit/?h=5.12&id=4d6832d03f31b513ff2e3517197691bedddaccdf > > https://code.qt.io/cgit/qt/qtbase.git/commit/?h=5.12&id=00326c9dc1ec6c80679347859c2fe01d4837b061 > > As you can see, most of the issues above are macOS specific. If our > application was Windows only, there would probably be much less need for > LTS versions and fewer regressions in Qt that affect our application. > > And you forgot to mention the most important thing, that there will never be 5.x QT usable on M1 macs. It means, that at least one year (depending, when qt-6 will be feature complete), every open source project based on QT will run on an M1 mac in emulation only (which does not work 100% perfectly). Tom -- Tomas Konir Czech Republic
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