Merge "aconfig: use an enum to represetn flag type" into main
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index c0ff5d2..67438e6 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -872,6 +872,7 @@
   target_info = common.BuildInfo(OPTIONS.info_dict, OPTIONS.oem_dicts)
   if OPTIONS.disable_vabc and target_info.is_release_key:
     raise ValueError("Disabling VABC on release-key builds is not supported.")
+
   ValidateCompressionParam(target_info)
   vabc_compression_param = target_info.vabc_compression_param
 
@@ -907,7 +908,6 @@
       logger.info("Source build and target build use different compression methods {} vs {}, default to source builds parameter {}".format(
           source_info.vabc_compression_param, target_info.vabc_compression_param, source_info.vabc_compression_param))
       vabc_compression_param = source_info.vabc_compression_param
-
     # Virtual AB Cow version 3 is introduced in Android U with improved memory
     # and install time performance. All OTA's with
     # both the source build and target build with VIRTUAL_AB_COW_VERSION = 3
@@ -918,6 +918,7 @@
     elif source_info.vabc_cow_version != target_info.vabc_cow_version:
       logger.info("Source and Target have different cow VABC_COW_VERSION specified, default to minimum version")
       OPTIONS.vabc_cow_version = min(source_info.vabc_cow_version, target_info.vabc_cow_version)
+
     # Virtual AB Compression was introduced in Androd S.
     # Later, we backported VABC to Android R. But verity support was not
     # backported, so if VABC is used and we are on Android R, disable
@@ -930,6 +931,19 @@
     assert "ab_partitions" in OPTIONS.info_dict, \
         "META/ab_partitions.txt is required for ab_update."
     source_info = None
+    if not target_info.vabc_cow_version:
+        OPTIONS.vabc_cow_version = 2
+    elif target_info.vabc_cow_version >= "3" and target_info.vendor_api_level < 35:
+      logger.warning(
+            "This full OTA is configured to use VABC cow version"
+            " 3 which is supported since"
+            " Android API level 35, but device is "
+            "launched with {} . If this full OTA is"
+            " served to a device running old build, OTA might fail due to "
+            "unsupported vabc cow version. For safety, version 2 is used because "
+            "it's supported since day 1.".format(
+                target_info.vendor_api_level))
+      OPTIONS.vabc_cow_version = 2
     if OPTIONS.vabc_compression_param is None and vabc_compression_param:
       minimum_api_level_required = VABC_COMPRESSION_PARAM_SUPPORT[
           vabc_compression_param]