Dive download crash - Qt model issues

[Linus Torvalds]

On Sat, Jun 24, 2017 at 10:54 AM, Thiago Macieira <thiago at macieira.org> wrote:
>
> Qt has release mode, debug mode and the "-developer-mode" switch. Be careful
> not to confuse the latter two: developer mode is debug mode but enables a few
> extra things so Qt's own unit tests can run, like exporting some functions so
> they can be called from the tests. Another consequence is that it compiles
> with -Werror and compiles each header individually, so the build time
> increases and you're more likely to get build failures.
>
> Unless you're developing Qt itself like me, you don't want that option. Debug
> mode is fine for debugging into Qt itself and enables Q_ASSERT.

The problem is that I have to build my own Qt library for the
bluetooth debugging, but I do *not* want to install it over the system
binaries (or, in fact, install it at all).

The solution to that problem is "--developer-build".  That actually
does exactly the right thing from a "build one single app against the
special Qt tree that has a couple of experimental patches"
perspective.

However, that solution is somewhat annoying, exactly because of things
like "-Werror" (which trigger errors that are compiler version
dependent, and in particular triggers errors in things like QtWebKit
that most Qt people don't seem to test because they prefer the
currently broken alternatives).

Honestly, I'd probably prefer a non-debug developer mode, but the
extra debug printouts it also seems to cause were actually super
helpful for getting BLE going.

The extra Q_ASSERT's? Yeah, not so much.

              Linus