add_dependencies early in build (IDFGH-13540) (PACMAN-981)

[malachib]

Answers checklist.

• [X] I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• [X] I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• [X] I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

I am working on a yaml generator. Its purpose is to work around the lack of local components ability to specify their own idf_component.yml.

It is working pretty well, but runs too late in the process. Although it runs before the components themselves are compiled, it runs after the component manager evaluates idf_component.yml.

It's very useful to run in the context of ESP-IDF build so that things like EXTRA_COMPONENT_DIRS is available.

Is there a way to add_dependencies such that my custom target is picked up by idf build early on, before managed components are evaluated?

[kumekay]

Hello @malachib, to help us better understand the problem, could you please elaborate why is it important in your case to add dependencies before idf_component.yml is processed and why is it too late otherwise? Maybe you have an example?

[malachib]

@kumekay Yes, gladly

Consider 3 components:

1. main component, primary firmware itself
2. lib1 component, consumed directly by main, a git submodule within main
3. lib2 component, consumed directly by lib1, a git submodule within lib1

As it stands, idf.py offers lib1 and lib2 no provision for an idf_component.yml. Only main has that option. I have a mechanism to scan lib1 and lib2 to populate idf_component.yml in main.

This is working. However, it happens too late in the build process for idf.py managed component mechanism to notice.

I can brute force it with execute_process but that bypasses the whole nice CMake target/dependency chain and additionally might exclude me from picking up things like EXTRA_COMPONENTS_DIR