Returns empty apex_infos if the apex target dir does not exist.

This is needed for partial builds that do not have the apex directory in
their target files package.

Test: build target files for a partial vendor-only build.
Change-Id: I076bfbd1a81cccddcef795f5edeaf2b51538cdec

tools/releasetools/add_img_to_target_files.py

@@ -64,7 +64,7 @@ import sparse_img
 import verity_utils
 import ota_metadata_pb2
 
-from apex_utils import GetApexInfoFromTargetFiles
+from apex_utils import GetSystemApexInfoFromTargetFiles
 
 if sys.hexversion < 0x02070000:
   print("Python 2.7 or newer is required.", file=sys.stderr)
@@ -757,7 +757,7 @@ def HasPartition(partition_name):
                            "{}.img".format(partition_name))))
 
 def AddApexInfo(output_zip):
-  apex_infos = GetApexInfoFromTargetFiles(OPTIONS.input_tmp)
+  apex_infos = GetSystemApexInfoFromTargetFiles(OPTIONS.input_tmp)
   apex_metadata_proto = ota_metadata_pb2.ApexMetadata()
   apex_metadata_proto.apex_info.extend(apex_infos)
   apex_info_bytes = apex_metadata_proto.SerializeToString()

tools/releasetools/apex_utils.py

@@ -516,7 +516,7 @@ def SignApex(avbtool, apex_data, payload_key, container_key, container_pw,
     raise ApexInfoError(
         'Failed to get type for {}:\n{}'.format(apex_file, e))
 
-def GetApexInfoFromTargetFiles(input_file):
+def GetSystemApexInfoFromTargetFiles(input_file):
   """
   Get information about system APEX stored in the input_file zip
 
@@ -538,6 +538,11 @@ def GetApexInfoFromTargetFiles(input_file):
     tmp_dir = UnzipTemp(input_file, ["SYSTEM/apex/*"])
   target_dir = os.path.join(tmp_dir, "SYSTEM/apex/")
 
+  # Partial target-files packages for vendor-only builds may not contain
+  # a system apex directory.
+  if not os.path.exists(target_dir):
+    return []
+
   apex_infos = []
 
   debugfs_path = "debugfs"

tools/releasetools/test_ota_from_target_files.py

@@ -33,7 +33,7 @@ from ota_from_target_files import (
     GetTargetFilesZipWithoutPostinstallConfig,
     Payload, PayloadSigner, POSTINSTALL_CONFIG,
     StreamingPropertyFiles, AB_PARTITIONS)
-from apex_utils import GetApexInfoFromTargetFiles
+from apex_utils import GetSystemApexInfoFromTargetFiles
 from test_utils import PropertyFilesTestCase
 
 
@@ -281,9 +281,9 @@ class OtaFromTargetFilesTest(test_utils.ReleaseToolsTestCase):
         metadata)
 
   @test_utils.SkipIfExternalToolsUnavailable()
-  def test_GetApexInfoFromTargetFiles(self):
+  def test_GetSystemApexInfoFromTargetFiles(self):
     target_files = construct_target_files(compressedApex=True)
-    apex_infos = GetApexInfoFromTargetFiles(target_files)
+    apex_infos = GetSystemApexInfoFromTargetFiles(target_files)
     self.assertEqual(len(apex_infos), 1)
     self.assertEqual(apex_infos[0].package_name, "com.android.apex.compressed")
     self.assertEqual(apex_infos[0].version, 1)