This change disallows Java modules in the vendor partition to use System
SDK that is newer than API level 34; 34 is the latest allowed.
Background 1: with Trunk Stable, the system/vendor interface is released
at Q2 whereas the system/app interface is released at Q3. In other
words, at Q2, the APIs which will be added to the system SDK at Q3 are
not available. Since the system/vendor interface (which is fronzen at
Q2) is what the modules in the vendor partition will be building
against, they can't and shouldn't use those new APIs that will be added
in the future (Q3). Using those APIs is risky because there's a chance
that those APIs get removed or changed between Q2 and Q3. For example,
2024 Q2 is technically still Android U, not Android V.
Background 2: The use of Java APIs in the vendor partition had many
issues. Most significantly, those "vendor" Java apps are categorized as
part of the system partition because all Java app processes require
access to platform internal libraries that are prohibited to vendor
processes. Furthermore, since the Project Treble, the vendor partition
was re-purposed to a partition to host SoC-dependent bits - usually
HALs. Implementing HALs in Java has never been officially supported and
has had many loop holes.
We'd like to use both background 1 and 2 as a chance to disallow any
Java code in the vendor partition. However, since there are already some
Java modules in the partition, we can't suddenly ban it. The deprecation
will be made gradually, and this CL is the start.
This CL implements the "Make" part of the restriction. The "Soong" part
will follow.
Note that LOCAL_SDK_VERSION := current or LOCAL_SDK_VERSION :=
system_current is automatically overridden into 34 or system_34. This is
to prevent sudden breakage of vendor modules that have been targetting
the latest (i.e. current) API level. They will however fail if they use
APIs newer than API level 34.
Bug: 314011075
Test: The following Android.mk module fails as expected.
some/Android.mk:
include $(CLEAR_VARS)
LOCAL_MODULE := example_module
LOCAL_VENDOR_MODULE := true
LOCAL_SDK_VERSION := system_35
LOCAL_SRC_FILES := Foo.java
include $(BUILD_JAVA_LIBRARY)
FAILED:
some/Android.mk: error: example_module: Incompatible
LOCAL_SDK_VERSION 'system_35'. System SDK version '35' is not supported.
Supported versions are: 28 29 30 31 32 33 34
Change-Id: I44c29c6dc45b91a9a30b8a21cd2baae685fa27fb
If BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES has a numeric value,
it replaces "current" or "system_current" with the version which
the flag indicates.
Bug: 163009188
Test: BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES=29 m, and then check if every vendor
java module's sdk_version is 29 if its sdk_version was current.
Change-Id: I8c7cf21563b984b8e9ef398192031b1f66d96494
