releasetools: Fix the bug when deleting files.

For file-based OTAs, we used to remove unneeded files in ascending
order, which failed to delete non-empty directories. Reverse the order
to fix the issue.

For example, now we have the following in our generated script:
  delete("/system/app/Calculator/arm/Calculator.odex",
         "/system/app/Calculator/arm/",
         "/system/app/Calculator/Calculator.apk",
         "/system/app/Calculator/");

Bug: 22960996
Change-Id: I0d36d29b7862fb53bf55bf5685a990180f9c0b3b

1 files changed, 7 insertions, 5 deletions

diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 7a11ba664b..d686004a96 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -1072,11 +1072,13 @@ class FileDifference(object):
       script.FileCheck(tf.name, tf.sha1)
 
   def RemoveUnneededFiles(self, script, extras=()):
-    script.DeleteFiles(
-        ["/" + i[0] for i in self.verbatim_targets] +
-        ["/" + i for i in sorted(self.source_data)
-         if i not in self.target_data and i not in self.renames] +
-        list(extras))
+    file_list = ["/" + i[0] for i in self.verbatim_targets]
+    file_list += ["/" + i for i in self.source_data
+                  if i not in self.target_data and i not in self.renames]
+    file_list += list(extras)
+    # Sort the list in descending order, which removes all the files first
+    # before attempting to remove the folder. (Bug: 22960996)
+    script.DeleteFiles(sorted(file_list, reverse=True))
 
   def TotalPatchSize(self):
     return sum(i[1].size for i in self.patch_list)