One more: If I have multiple modules, are multithreaded builds enabled by default? I always thought so, because the tasks interleave during build. But now Ive tried org.gradle.parallel=true, and get 30% speedup, is this parallel a different thing?

No, Gradle will not run builds of multiple modules in parallel by default, you have to specify org.gradle.parallel=true explicitly

Thats weird, so Ive been modularized for few months for nothing? lol, However the build speed did improve even withouth the flag

not being in parallel doesn't mean it doesn't have advantages compile avoidance ( if you don't use kotlin ) build cache ...

true, but why would you not want parallel builds if you already have the separation

because Gradle cannot assume your modules are independant

how would they not be independant? they are modules = independant, no?

even thought they could have made it a default on Gradle 5.0

huhm compile avoidance doesnt work if I use kotlin?

you can add sourceSets or resources from other modules ( which is kind of stupid )

oh, yea thats silly

and no, compile avoidance doesn't work YET with Kotlin

Im always strugging with gradle flags, as to what actuallydoes something

I would say kotlin.incremental is true be default, but I don't remember from which version

okay so now in kotlin if I change something in base module, every other module that includes base will be recompiled?

yes

but, if I change feature1, then feature 2 (they are totally unrelated) doesnt get recompiled, right?

in java if the change you made on base is only an implementation detail no other module would recompile

okay so basically my

implementation

includes do nothing for now?

¿?

to get compilation avoidance I thought

implementation

including of modules is necessary

implementation does not propagate the dependency, so it helps too

what about that caching please?

Implementation/api != compile avoidance

any good articles on this subject? Given: a few base modules plus feature modules on the top, all kotlin. How to speed this shit up? (I've checked the corresponding section on developer.android)

not sure about feature/base module, because it’s one more level of dependencies on top usual Gradle modules. In general to speedup you should have more independent modules (maybe even not related on feature/base, just module with minimum dependencies, to make it recompilation recompile only modules that depend on it) But it’s pretty wide topic, I would recommend first check you build scan to understand what is slow. Also as starting point check this webinar from Gradle team https://gradle.com/blog/improving-android-and-java-build-performance/

@gildor what do you mean another level of modules, its the usual diamon :base -> :feature(s) -> :app

I mean there are usual Gradle modules (projects) but when someone talks about base/feature modules in domain of Android it probably about instant app/app bundle dynamic modules which is additional feature where module dependencies are inverted (feature has base module in dependencies and base has list of dynamic features, and base module is your application for app bundle) And I just don't know how this works in terms of Gradle compilation

oh, well I see people use base/core + features terminology as well in regular multimodule

Yes, but it’s very confusing to use base/feature for usual gradle modules, because base and feature is even Gradle plugin name for app bundle/instan app modiles, that my point. Core is fine, at least it’s clear that core is root of other module and doesn’t have dependencies to other core modules