commit 4f5d0e60b441f009f78ef6595172ffa11dd69a2d
author Ying Wang <wangying@google.com> Mon May 04 19:21:48 2015 -0700
committer Ying Wang <wangying@google.com> Tue May 05 17:35:12 2015 +0000
tree 68397b48f929bc8c6d16d54efc7cb35ce9883758
parent 5c73ba6e037f3e145fcc84ad2329a002ddb3bf54

Raise SDK version for ProGuard processing when app links support library.

When an app's LOCAL_SDK_VERSION is lower than the support library's
LOCAL_SDK_VERSION,  we artifically raises the "SDK version" "linked"
by ProGuard, to
- suppress ProGuard warnings of referencing symbols unknown to the
  lower SDK version.
- prevent ProGuard stripping subclass in the support library that
  extends class added in the higher SDK version.

This allows us to remove the dangerous ProGuard flag
"-dontwarn android.support.**".

Notes:
- We don't raise the app's LOCAL_SDK_VERSION, so that the app's own
  code is still unable to use the higher SDK version.
- For platform build, we can't just raise to the "current" SDK,
  because would break apps that use APIs removed from the current SDK.
  We raise it to framework.jar instead, which contains the most complete
  symbol set.

Bug: 20658265
Change-Id: I90099073457a65cb8031fbaec6b396d68ce614a7
(cherry picked from commit 8e8d1e7abadb53d5dcb211fac6ab6ed20f5dc9ac)

core/java.mk

diff --git a/core/java.mk b/core/java.mk
index 02745a8..73b8780 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -432,8 +432,29 @@
     $(error invalid value for LOCAL_PROGUARD_ENABLED: $(LOCAL_PROGUARD_ENABLED))
 endif
 proguard_dictionary := $(intermediates.COMMON)/proguard_dictionary
+
+# Hack: see b/20667396
+# When an app's LOCAL_SDK_VERSION is lower than the support library's LOCAL_SDK_VERSION,
+# we artifically raises the "SDK version" "linked" by ProGuard, to
+# - suppress ProGuard warnings of referencing symbols unknown to the lower SDK version.
+# - prevent ProGuard stripping subclass in the support library that extends class added in the higher SDK version.
+my_support_library_sdk_raise :=
+ifneq (,$(filter android-support-%,$(LOCAL_STATIC_JAVA_LIBRARIES)))
+ifdef LOCAL_SDK_VERSION
+ifeq (,$(filter current system_current, $(LOCAL_SDK_VERSION)))
+ifdef TARGET_BUILD_APPS
+  my_support_library_sdk_raise := $(call java-lib-files, sdk_vcurrent)
+else
+  # For platform build, we can't just raise to the "current" SDK,
+  # that would break apps that use APIs removed from the current SDK.
+  my_support_library_sdk_raise := $(call java-lib-files,framework)
+endif
+endif
+endif
+endif
+
 # jack already has the libraries in its classpath and doesn't support jars
-legacy_proguard_flags := $(addprefix -libraryjars ,$(full_shared_java_libs))
+legacy_proguard_flags := $(addprefix -libraryjars ,$(my_support_library_sdk_raise) $(full_shared_java_libs))
 common_proguard_flags :=  \
                   -forceprocessing \
                   -printmapping $(proguard_dictionary)
@@ -501,7 +522,7 @@
 endif
 $(full_classes_proguard_jar): PRIVATE_EXTRA_INPUT_JAR := $(extra_input_jar)
 $(full_classes_proguard_jar): PRIVATE_PROGUARD_FLAGS := $(legacy_proguard_flags) $(common_proguard_flags) $(LOCAL_PROGUARD_FLAGS)
-$(full_classes_proguard_jar) : $(full_classes_jar) $(extra_input_jar) $(proguard_flag_files) | $(ACP) $(PROGUARD)
+$(full_classes_proguard_jar) : $(full_classes_jar) $(extra_input_jar) $(my_support_library_sdk_raise) $(proguard_flag_files) | $(ACP) $(PROGUARD)
 	$(call transform-jar-to-proguard)
 
 else  # LOCAL_PROGUARD_ENABLED not defined