Possibility of backporting Qt bug fixes

One of my applications (Sailfin) is freezing due a deadlock within Qt caused by QTBUG-76157. This has been fixed with a patch in several Qt versions above 5.12.5. I’ve modified and applied this patch to the Jolla branch of Qt myself. This solves the freezing for my application and somehow I managed to do apply this patch to a core system component without soft bricking my phone :slight_smile:

Anyhow, are there any chances that such bug fixes from the upstream Qt repository could be backported to the Jolla branch? I’ve heard rumours about it not being possible due to licensing issues with the newer Qt versions and the fact that OpenSSL 1.1 on the Jolla branch has been implemented in a different way than in the upstream Qt versions supports this rumour.

A Qt upgrade to a Qt version that fixes this and other bugs, such as 5.12.5, would be even better, but I’ve seen people asking about it since I started using Sailfish OS. I expect the answer to that request to be the same as the answer given to all the people who’ve requested it before me.

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Indeed, patches are protected by the same licenses as the code itself and newer Qt licensing seems to be an issue with Jolla.

Depending on the size of the patch and your willingness to rewrite it, you can submit a PR to sailfishos/qtbase. I’ve done it already, for instance : [qtbase] Fix QDateTime::toString() timezone info. Contributes to JB#5… · sailfishos/qtbase@74afde0 · GitHub

That’s a boring situation :-/

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I’d be willing to rewrite it. I had to rewrite it for the patch anyway, since quite a bit has changed between Qt 5.6 and Qt 5.12 in qtnetwork. However, the patch is not trivial and I have seen the actual changes that Qt made. The patch that I would write would be influenced by that code, even if I would not look at Qt’s newer code from now on. I’m not sure if that’s allowed by the licence and copyright law. Neither do I know what Jolla’s policies are on this matter.

Alternatively, I could wait 70 years or so for the copyright on the source code to expire :wink:

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Well, as far as I understand the full topic, ideas cannot be copyrighted (at least in Europe). It’s their implementations that are (there is no software patents but there are copyrights on written productions). I don’t see any issue in reading a copyrighted code, understanding it’s intent and reimplementing it, as long as there will be no copy-pasting in the process. Well, that’s my personal interpretation. I guess layers may diverge on the matter.

As far as I know, Jolla sailors may not complain on your PR as long as there is no copy-pasting (copying by hand can be considered as a bad implementation of copy-pasting in that regard).

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