From b6dc25a368ce68f557d31c854728ee4e2071c0cf Mon Sep 17 00:00:00 2001
From: Peter Gerber <peter@arbitrary.ch>
Date: Sat, 11 May 2019 12:00:58 +0200
Subject: [PATCH] Reproducible build: Ensure apkdiff.py works properly again
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The recent switch to Python3 (2ccdf0e396e82dd) introduced a regression
that led to file content no longer being compared:

   In compareEntries(), two generators/iterators are created:

     sourceInfoList      = filter(lambda sourceInfo: …, sourceZip.infolist())
     destinationInfoList = filter(lambda destinationInfo: …, destinationZip.infolist())

   Few lines later, those are exhausted:

     if len(sourceInfoList) != len(destinationInfoList):

   Yet another few lines later, the exhausted generator is used again:

     for sourceEntryInfo in sourceInfoList:
        …          # <-- unreachable

This is caused by behavioral differences between Python2 and Python3:

   user@z_signal:~$ python2
   Python 2.7.13 (default, Sep 26 2018, 18:42:22)
   [GCC 6.3.0 20170516] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> f = filter(lambda i: i % 2 == 0, [0, 1, 2, 3, 4, 5, 6])
   >>> list(f)
   [0, 2, 4, 6]
   >>> list(f)
   [0, 2, 4, 6]
   >>>

   user@z_signal:~$ python3
   Python 3.5.3 (default, Sep 27 2018, 17:25:39)
   [GCC 6.3.0 20170516] on linux
   Type "help", "copyright", "credits" or "license" for more information.
   >>> f = filter(lambda i: i % 2 == 0, [0, 1, 2, 3, 4, 5, 6])
   >>> list(f)
   [0, 2, 4, 6]
   >>> list(f)
   []
   >>>
---
 apkdiff/apkdiff.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/apkdiff/apkdiff.py b/apkdiff/apkdiff.py
index ff1cc4981..da19bf59d 100755
--- a/apkdiff/apkdiff.py
+++ b/apkdiff/apkdiff.py
@@ -35,10 +35,10 @@ class ApkDiff:
         return True
 
     def compareEntries(self, sourceZip, destinationZip):
-        sourceInfoList      = filter(lambda sourceInfo: sourceInfo.filename not in self.IGNORE_FILES, sourceZip.infolist())
-        destinationInfoList = filter(lambda destinationInfo: destinationInfo.filename not in self.IGNORE_FILES, destinationZip.infolist())
+        sourceInfoList      = list(filter(lambda sourceInfo: sourceInfo.filename not in self.IGNORE_FILES, sourceZip.infolist()))
+        destinationInfoList = list(filter(lambda destinationInfo: destinationInfo.filename not in self.IGNORE_FILES, destinationZip.infolist()))
 
-        if len(list(sourceInfoList)) != len(list(destinationInfoList)):
+        if len(sourceInfoList) != len(destinationInfoList):
             print("APK info lists of different length!")
             return False
 
@@ -61,7 +61,7 @@ class ApkDiff:
         sourceChunk      = sourceFile.read(1024)
         destinationChunk = destinationFile.read(1024)
 
-        while sourceChunk != "" or destinationChunk != "":
+        while sourceChunk != b"" or destinationChunk != b"":
             if sourceChunk != destinationChunk:
                 return False