[Development] Behavior-changing bugfixes in patch-level releases

[EXT Mitch Curtis]

Hi Arno,

> -----Original Message-----
> From: Development <development-bounces at qt-project.org> On Behalf Of
> Arno Rehn
> Sent: Wednesday, July 12, 2023 3:01 PM
> To: Qt development mailing list <development at qt-project.org>
> Subject: [Development] Behavior-changing bugfixes in patch-level releases
> 
> Hey everyone,
> 
> what is the policy for adding behavior-changing bugfixes to patch-level
> releases? Is this something to expect?
> At the moment we operate under the assumption that bumping the patch-
> level of Qt is pretty much a no-brainer and can be done without having to do
> much in the way of validation.
> 
> If behavior changes in patch-level releases are to be expected, we'll have to be
> more careful with bumping Qt.
> 
> Context: We have been hit by
> https://codereview.qt-project.org/c/qt/qtdeclarative/+/472596 (which is
> even marked as "Important Behavior Change") ending up only in 6.5.1.
> It was quite the headache figuring out that 6.5.0 -> 6.5.1 has broken part of
> our ListViews.

I'm sorry to hear that.

As the developer who approved the change, I've left my thoughts here:

https://bugreports.qt.io/browse/QTBUG-114166?focusedId=734562&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-734562

In summary, I believe the official branch policy was followed here.

I'm not sure if your use case is the same as the snippet in the bug report, so it would be useful if you could share it so that we can see if there's a legitimate usage that we've broken. That's not to say that it's good to introduce regressions, of course, but often it's hard to know how users are using APIs and we often only find out after the change has been merged, because auto tests can't cover every use case for the same reason.

> Regards,
> Arno
> 
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