Revert "Revert "Limit System SDK to 34 for Java modules in the v..."

Revert submission 2897568-revert-2894701-limit_systemsdk-WNEMOTGMRS

Reason for revert: Forward fix was merged

Reverted changes: /q/submissionid:2897568-revert-2894701-limit_systemsdk-WNEMOTGMRS

Change-Id: Ia103db05bfaebdfd301dbf84183a89d01f58eb67
diff --git a/core/base_rules.mk b/core/base_rules.mk
index a446483..254bfeb 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -121,9 +121,17 @@
    $(LOCAL_PROPRIETARY_MODULE))
 
 include $(BUILD_SYSTEM)/local_vndk.mk
-include $(BUILD_SYSTEM)/local_systemsdk.mk
+
+# local_current_sdk needs to run before local_systemsdk because the former may override
+# LOCAL_SDK_VERSION which is used by the latter.
 include $(BUILD_SYSTEM)/local_current_sdk.mk
 
+# Check if the use of System SDK is correct. Note that, for Soong modules, the system sdk version
+# check is done in Soong. No need to do it twice.
+ifneq ($(LOCAL_MODULE_MAKEFILE),$(SOONG_ANDROID_MK))
+include $(BUILD_SYSTEM)/local_systemsdk.mk
+endif
+
 # Ninja has an implicit dependency on the command being run, and kati will
 # regenerate the ninja manifest if any read makefile changes, so there is no
 # need to have dependencies on makefiles.
diff --git a/core/local_current_sdk.mk b/core/local_current_sdk.mk
index ea7da8a..ccdbf77 100644
--- a/core/local_current_sdk.mk
+++ b/core/local_current_sdk.mk
@@ -14,13 +14,24 @@
 # limitations under the License.
 #
 ifdef BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES
-  ifneq (current,$(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES))
+  _override_to := $(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES)
+
+  # b/314011075: apks and jars in the vendor or odm partitions cannot use
+  # system SDK 35 and beyond. In order not to suddenly break those vendor
+  # modules using current or system_current as their LOCAL_SDK_VERSION,
+  # override it to 34, which is the maximum API level allowed for them.
+  ifneq (,$(filter JAVA_LIBRARIES APPS,$(LOCAL_MODULE_CLASS)))
+    _override_to := 34
+  endif
+
+  ifneq (current,$(_override_to))
     ifneq (,$(filter true,$(LOCAL_VENDOR_MODULE) $(LOCAL_ODM_MODULE) $(LOCAL_PROPRIETARY_MODULE)))
       ifeq (current,$(LOCAL_SDK_VERSION))
-        LOCAL_SDK_VERSION := $(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES)
+        LOCAL_SDK_VERSION := $(_override_to)
       else ifeq (system_current,$(LOCAL_SDK_VERSION))
-        LOCAL_SDK_VERSION := system_$(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES)
+        LOCAL_SDK_VERSION := system_$(_override_to)
       endif
     endif
   endif
+  _override_to :=
 endif
diff --git a/core/local_systemsdk.mk b/core/local_systemsdk.mk
index 460073d..fcde700 100644
--- a/core/local_systemsdk.mk
+++ b/core/local_systemsdk.mk
@@ -33,6 +33,9 @@
           # Runtime resource overlays are exempted from building against System SDK.
           # TODO(b/155027019): remove this, after no product/vendor apps rely on this behavior.
           LOCAL_SDK_VERSION := system_current
+          # We have run below again since LOCAL_SDK_VERSION is newly set and the "_current"
+          # may have to be updated
+          include $(BUILD_SYSTEM)/local_current_sdk.mk
         endif
       endif
     endif
@@ -54,7 +57,30 @@
     # If not, vendor apks are treated equally to system apps
     _supported_systemsdk_versions := $(PLATFORM_SYSTEMSDK_VERSIONS)
   endif
+
+  # b/314011075: apks and jars in the vendor or odm partitions cannot use system SDK 35 and beyond.
+  # This is to discourage the use of Java APIs in the partitions, which hasn't been supported since
+  # the beginning of the project Treble back in Android 10. Ultimately, we'd like to completely
+  # disallow any Java API in the partitions, but it shall be done progressively.
+  ifneq (,$(filter true,$(LOCAL_VENDOR_MODULE) $(LOCAL_ODM_MODULE) $(LOCAL_PROPRIETARY_MODULE)))
+    # 28 is the API level when BOARD_SYSTEMSDK_VERSIONS was introduced. So, it's the oldset API
+    # we allow.
+    _supported_systemsdk_versions := $(call int_range_list, 28, 34)
+  endif
+
+  # Extract version number from LOCAL_SDK_VERSION (ex: system_34 -> 34)
   _system_sdk_version := $(call get-numeric-sdk-version,$(LOCAL_SDK_VERSION))
+  # However, the extraction may fail if it doesn't have any number (i.e. current, core_current,
+  # system_current, or similar) Then use the latest platform SDK version number or the actual
+  # codename.
+  ifeq (,$(_system_sdk_version)
+    ifeq (REL,$(PLATFORM_VERSION_CODENAME))
+      _system_sdk_version := $(PLATFORM_SDK_VERSION)
+    else
+      _system_sdk_version := $(PLATFORM_VERSION_CODENAME)
+    endif
+  endif
+
   ifneq ($(_system_sdk_version),$(filter $(_system_sdk_version),$(_supported_systemsdk_versions)))
     $(call pretty-error,Incompatible LOCAL_SDK_VERSION '$(LOCAL_SDK_VERSION)'. \
            System SDK version '$(_system_sdk_version)' is not supported. Supported versions are: $(_supported_systemsdk_versions))