Copy of libraries via Android.mk

[Tiago Vieira]

Hi

I've been struggling for sometime with copies of unnecessary libraries into the build when I don't need them.

I have within vendor/<company>/libs the file Android.mk and library.so.

The Android.mk is defined like:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_PREBUILT_LIBS := superlibrary.so
include $(BUILD_MULTI_PREBUILT)

Within vendor/<company>/apps I have Android.mk and application.apk.

Android.mk is defined like:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := application
LOCAL_MODULE_TAGS := optional
LOCAL_SRC_FILES := $(LOCAL_MODULE).apk
LOCAL_MODULE_CLASS := APPS
LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)
LOCAL_REQUIRED_MODULES := superlibrary
LOCAL_CERTIFICATE := PRESIGNED
include $(BUILD_PREBUILT)

So, application is tagged as optional. I then add the application within my product (PRODUCT_PACKAGES) and after the build I can see:

- system/app/application.apk
- system/lib/superlibrary.so

But, when I don't add 'application' into the PRODUCT_PACKAGES, the application is not installed, but superlibrary.so will be always in the system/lib.

What is missing in my Android.mk for the library that is copying the file unconditionally to the system lib? I would like to copy it only when the 'application' is installed.

Looking for different ways, I see a lot of "PRODUCT_COPY_FILES" copying the libraries instead of using the mechanism above. Is the way I'm using deprecated?

Any help will be very welcome.

Thanks,
Tiago

[Jean-Baptiste Queru]

A common pitfall, unfortunately.

The issue is that prebuilts default to LOCAL_MODULE_TAGS=user, which
causes them to be included in all builds regardless of whether they're
specified in PRODUCT_PACKAGES. This is a legacy behavior fromyears
ago.

In theory, all you need to do is add LOCAL_MODULE_TAGS := optional for
your prebuilt. In reality, I'm not sure that BUILD_MULTI_PREBUILT
supports it in froyo.

Looking ahead, starting with Gingerbread, we've decided to "stop the
bleeding": any new module that uses LOCAL_MODULE_TAGS := user
(implicitly or explicitly) and isn't on a whitelist will cause the
build to fail. This is how we (Google) are making sure that none of
our new modules use that mis-feature, without spending the time to
evaluate the existing ~1000 modules which are known to be OK. We're
also cutting off 2 other mechanisms that could cause an Android.mk to
cause files to be copied to the target without involving product
makefiles (modifying ALL_PREBUILT, and modifying PRODUCT_COPY_FILES).

JBQ

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--
Jean-Baptiste M. "JBQ" Queru
Software Engineer, Android Open-Source Project, Google.

Questions sent directly to me that have no reason for being private
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