Comment 5 for bug 1827288

The version number in the debian/changelog of the git branch is wrong; this needs to be a non-native package using the upstream tarball from sourceforge.

+ libjack-jackd2-dev | libjack-dev,
+ php7.2-cli | php5-cli,
+ cairo-static | libcairo2-dev,

why are you using alternative build-dependencies for a new, Ubuntu-only package? You should only list whichever of these build dependencies you actually expect to be used (and there is no cairo-static package in Ubuntu anywhere, so that is definitely wrong).

Please use php-cli, not phpN.M-cli, as the build-dependency.

+Provides:
+ lv2-plugin,
+ ladspa-plugin,

Why are these Provides: attached to the lsp-plugins package, when there are separate lsp-plugins-ladspa and lsp-plugins-lv2 packages? The Provides look like they belong on the latter packages.

+Package: lsp-plugins-common
+Architecture: any
+Provides: lsp-plugins-standalone

Something is definitely wrong here given that you also have a binary package named lsp-plugins-standalone which depends on lsp-plugins-common. In fact, lsp-plugins-standalone appears to be an empty package; so you should not list this binary package at all in debian/control.

+FLAGS=-O3 -pipe -ffast-math -mtune=generic -msse -msse2 -mfpmath=sse -fPIC -DPIC -fvisibility=hidden -Wno-unused-result

How have you arrived at these flags? Compiler flags should a) inherit from dpkg-buildflags by default (You are completely overriding them), and b) document the reasons for any divergence from the distro defaults.

But actually, it seems that the only thing you're doing is setting these flags in a make variable called 'dpkg_buildflags', so in fact this has no effect at all.

Not that you could tell by looking at the build log, which does not show the compiler commands being invoked. This is significant for debuggability of builds in launchpad. Please figure out how to make this upstream's build system appropriately verbose.

+override_dh_auto_test:
+ #Tests only work manually, ok to override per http://manpages.ubuntu.com/manpages/disco/en/man1/dh_auto_test.1.html
+

what are these tests, and why do they only work manually? It's /allowed/ to override tests, but the goal should be to run them.