update: purge system clock check, APKs no longer have dates in them

A long time ago, APKs' ZIP headers usually included the dates that the
files where actually created.  That was a source of current date/time info
for fully offline signing servers, e.g. if the system clock was set to a
time older than included in the APK, then it was probably wrong.

For reproducibility, those dates have been zeroed out since long ago. So
now this is no longer useful since the dates are always 1980-01-01.

fdroidserver/common.py

@@ -79,7 +79,7 @@ import zipfile
 from argparse import BooleanOptionalAction
 from base64 import urlsafe_b64encode
 from binascii import hexlify
-from datetime import datetime, timedelta, timezone
+from datetime import datetime, timezone
 from pathlib import Path
 from queue import Queue
 from typing import List
@@ -2894,23 +2894,6 @@ def natural_key(s):
     return [int(sp) if sp.isdigit() else sp for sp in re.split(r'(\d+)', s)]
 
 
-def check_system_clock(dt_obj, path):
-    """Check if system clock is updated based on provided date.
-
-    If an APK has files newer than the system time, suggest updating
-    the system clock.  This is useful for offline systems, used for
-    signing, which do not have another source of clock sync info. It
-    has to be more than 24 hours newer because ZIP/APK files do not
-    store timezone info
-
-    """
-    checkdt = dt_obj - timedelta(1)
-    if datetime.today() < checkdt:
-        logging.warning(_('System clock is older than date in {path}!').format(path=path)
-                        + '\n' + _('Set clock to that time using:') + '\n'
-                        + 'sudo date -s "' + str(dt_obj) + '"')
-
-
 def get_file_extension(filename):
     """Get the normalized file extension, can be blank string but never None."""
     if isinstance(filename, bytes):

fdroidserver/update.py

@@ -36,7 +36,6 @@ import time
 import warnings
 import zipfile
 from argparse import ArgumentParser
-from datetime import datetime
 from pathlib import Path
 
 import asn1crypto.cms
@@ -2207,23 +2206,10 @@ def process_apk(apkcache, apkfilename, repodir, package_added_cache, use_date_fr
                                 .format(apkfilename=apkfilename))
             return True, None, False
 
-        apkzip = zipfile.ZipFile(apkfile, 'r')
-
-        manifest = apkzip.getinfo('AndroidManifest.xml')
-        # 1980-0-0 means zeroed out, any other invalid date should trigger a warning
-        if (1980, 0, 0) != manifest.date_time[0:3]:
-            try:
-                common.check_system_clock(datetime(*manifest.date_time), apkfilename)
-            except ValueError as e:
-                logging.warning(_("{apkfilename}'s AndroidManifest.xml has a bad date: ")
-                                .format(apkfilename=apkfile) + str(e))
-
         # extract icons from APK zip file
         iconfilename = get_old_icon_filename(apk['packageName'], apk['versionCode'])
-        try:
+        with zipfile.ZipFile(apkfile, 'r') as apkzip:
             empty_densities = extract_apk_icons(iconfilename, apk, apkzip, repodir)
-        finally:
-            apkzip.close()  # ensure that APK zip file gets closed
 
         # resize existing icons for densities missing in the APK
         fill_missing_icon_densities(empty_densities, iconfilename, apk, repodir)