pw_build: pw_facade require_link_deps arg
- Make the pw_build_LINK_DEPS check in pw_assert a generic feature in
pw_facade.
- Use "impl" instead of "deps" for the pw_assert dependencies and
restructure the impl / backend split.
Change-Id: I75c0f7e67b3b97bfe333760897223ab4601649c0
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/43980
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Ewout van Bekkum <ewout@google.com>
Reviewed-by: Armando Montanez <amontanez@google.com>
diff --git a/pw_build/docs.rst b/pw_build/docs.rst
index ad43bff..a5d38da 100644
--- a/pw_build/docs.rst
+++ b/pw_build/docs.rst
@@ -125,6 +125,14 @@
public = [ "public/pw_foo/foo.h" ]
}
+Low-level facades like ``pw_assert`` cannot express all of their dependencies
+due to the potential for dependency cycles. Facades with this issue may require
+backends to place their implementations in a separate build target to be listed
+in ``pw_build_LINK_DEPS`` (see :ref:`module-pw_build-link-deps`). The
+``require_link_deps`` variable in ``pw_facade`` asserts that all specified build
+targets are present in ``pw_build_LINK_DEPS`` if the facade's backend variable
+is set.
+
.. _module-pw_build-python-action:
pw_python_action