make: handle disabled default modules before dependencies

[kaspar030]

Contribution description

Currently, default modules can be disabled by adding the name to DISABLE_MODULE.
Unfortunately, this gets parsed after resolving the dependencies.

This makes it impossible to disable e.g., stdio_uart and implicitly periph/uart. The dependency parsing would select periph/uart (as it is dependend on stdio_uart), but later stdio_uart would be dropped, leaking the dependency.

This PR moves DISABLE_MODULE before dependency resolution.

Testing procedure

Correct compilation of all applications should suffice.

Issues/PRs references

#10741

[basilfx]

Maybe I'm using/understanding it wrong, but it isn't working for me.

I have a board that includes stdio_rtt in its Makefile.dep. Now I want to compile it with stdio_rtt disabled (and default to stdio_uart since it's the default).

I run DISABLE_MODULE=stdio_rtt BOARD=basilfx-taster make -j8 and I get this error:

DISABLE_MODULE="stdio_uart" BOARD=basilfx-taster make -j8
Required modules were disabled using DISABLE_MODULE: stdio_uart

EXPECT ERRORS!

examples/gnrc_knx_taster/../../Makefile.include:737: examples/gnrc_knx_taster/bin/basilfx-taster/stdio_uart.a
examples/gnrc_knx_taster/../../Makefile.include:739: *** BASELIBS value changed.  Stop.

[kaspar030]

Maybe I'm using/understanding it wrong, but it isn't working for me.

Unfortunately, despite it's naming, DISABLE_MODULE only works for DEFAULT_MODULES.

This PR is the first, there are more to come that together will allow disabling stdio_uart...

[cgundogan]

Sensible change. ACK

[cladmi]

The only definitions of DEFAULT_MODULE were in makefiles/defaultmodules.inc.mk and one in cpu/msp430_common/Makefile.include for some reason, so has no bad impact now when looking at which modules are inside.

However, I do not really understood the issue that it will solve. The values in DEFAULT_MODULE are rather generic mechanisms that are included in a normal firmware, and modules you are supposed to find there.

I also mix a bit the order with depends on is dependent on so cannot really see the goal right now.

If A depends on B, you disable B, but still request A. I would maybe expect it to fail, not silently add B because it is a dependency. I do not think that you should able to say add and remove something at the same time.
Even more right now when it is for generic things like there is in the DEFAULT_MODULE list.

But we may indeed be missing a mechanism for your need.