[Do Not Merge] break < Qt5.6 compatibility for addAction to test Travis #15320

This reverts commit 3e21b690d1aedb73a7dc2bc5d2ff1b011b52d927 from #14979.

#15308 should catch this

#15308 was only about boost. I have no opinion what our minimum supported version for qt should be.

Anyway, this should fail because xenial has qt5.5

Yeah I have a follow-up which should cover qt 5.4 - will have that up later today.

Incidentally, a good way to run these checks without a PR is to set up the repo on your personal travis account: https://travis-ci.org/sjors/bitcoin. e.g. https://travis-ci.org/Empact/bitcoin

The Trusty build passed though.

I'm confused; #15308 switched Trusty (not Xenial) to NO_DEPENDS=1 which means it uses the package manager version QT, which should be 5.2:

<img width="492" alt="schermafbeelding 2019-02-02 om 08 30 04" src="https://user-images.githubusercontent.com/10217/52161395-c3af4580-26c4-11e9-88ab-54840497935c.png">

So the Trusty build should have failed, but didn't.

I realized I could have run it on my own repo about two seconds after making the PR :-)

See the --with-gui=no ;)

https://github.com/bitcoin/bitcoin/blob/b3a715301a0fd972fb2f3bd36e2680b3cdbbab26/.travis.yml#L112

@MarcoFalke aha, so we're installing QT just for shits & giggles on that machine? :-)

For now, yes

#14998 has fixes for a few QT 5.2 issues, for example the current failure is fixed by 352f36e01c8b392ee785bfb356e71488858e5da8

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Conflicts

No conflicts as of last run.

@MarcoFalke when I enable GUI build on Trusty the compile fails as expected. Would that be safe to enable for Travis? No need to run the tests.

Ah wait, it's more confusing actually :-)

When I enable GUI build, Travis blows up on a different error than the one I deliberately introduced. Namely the error @Empact fixes in 352f36e01c8b392ee785bfb356e71488858e5da8 (no PR).

So in order to enable the GUI build like I did in 573d5af we'd have to add 352f36e01c8b392ee785bfb356e71488858e5da8 as well, otherwise all builds will fail.

<img width="1049" alt="schermafbeelding 2019-02-10 om 20 06 20" src="https://user-images.githubusercontent.com/10217/52538234-63796d00-2d70-11e9-84a7-92240c561899.png">

I cherry-picked 352f36e to see if Travis Trusty now fails with the error I expect.

That didn't seem to help much (log):

<img width="1083" alt="schermafbeelding 2019-02-11 om 13 13 16" src="https://user-images.githubusercontent.com/10217/52562454-db8e7400-2dfe-11e9-961d-b70f906dbcb8.png">

Meanwhile Xenial uses QT 5.5 and does correctly break (log) on the addAction stuff.

The minimum QT version was bumped to 5.5.1 in #15393, so I dropped the check for QT 5.4 and 5.2 from this PR. If all goes well only the QT 5.5.1 Xenial Travis job (8) should fail, and then I'll close this.

@Sjors It failed

@MarcoFalke so did job 9 due to a timeout. Restarted, but I'm optimistic :-)

<img width="1109" alt="schermafbeelding 2019-02-22 om 10 05 08" src="https://user-images.githubusercontent.com/10217/53231497-5a9a6c80-3689-11e9-854a-58452a64ec55.png">