update: handle large, corrupt, or inaccessible fastlane/triple-t files

```
Traceback (most recent call last):
  File "../fdroid", line 22, in <module>
    fdroidserver.__main__.main()
  File "/var/lib/jenkins/userContent/reproducible/reproducible_fdroid_build_apps/fdroidserver/__main__.py", line 227, in main
    raise e
  File "/var/lib/jenkins/userContent/reproducible/reproducible_fdroid_build_apps/fdroidserver/__main__.py", line 208, in main
    mod.main()
  File "/var/lib/jenkins/userContent/reproducible/reproducible_fdroid_build_apps/fdroidserver/update.py", line 2340, in main
    repoapps = prepare_apps(apps, apks, repodirs[0])
  File "/var/lib/jenkins/userContent/reproducible/reproducible_fdroid_build_apps/fdroidserver/update.py", line 2176, in prepare_apps
    copy_triple_t_store_metadata(apps_with_packages)
  File "/var/lib/jenkins/userContent/reproducible/reproducible_fdroid_build_apps/fdroidserver/update.py", line 1076, in copy_triple_t_store_metadata
    _set_author_entry(app, 'authorWebSite', os.path.join(root, f))
  File "/var/lib/jenkins/userContent/reproducible/reproducible_fdroid_build_apps/fdroidserver/update.py", line 784, in _set_author_entry
    with open(f, errors='replace') as fp:
FileNotFoundError: [Errno 2] No such file or directory: 'build/player.efis.cfd/pfd/src/main/play/contact-website.txt'
```

fdroidserver/update.py

@@ -768,23 +768,41 @@ def _get_localized_dict(app, locale):
 
 
 def _set_localized_text_entry(app, locale, key, f):
+    """Read a fastlane/triple-t metadata file and add an entry to the app
+
+    This reads more than the limit, in case there is leading or
+    trailing whitespace to be stripped
+
+    """
+    try:
         limit = config['char_limits'][key]
         localized = _get_localized_dict(app, locale)
         with open(f, errors='replace') as fp:
-        text = fp.read()[:limit]
+            text = fp.read(limit * 2)
             if len(text) > 0:
                 if key in ('name', 'summary', 'video'):  # hardcoded as a single line
-                localized[key] = text.strip('\n')
+                    localized[key] = text.strip('\n')[:limit]
                 else:
-                localized[key] = text
+                    localized[key] = text[:limit]
+    except Exception as e:
+        logging.error(_('{path}: {error}').format(path=f, error=str(e)))
 
 
 def _set_author_entry(app, key, f):
+    """read a fastlane/triple-t author file and add the entry to the app
+
+    This reads more than the limit, in case there is leading or
+    trailing whitespace to be stripped
+
+    """
+    try:
         limit = config['char_limits']['author']
         with open(f, errors='replace') as fp:
-        text = fp.read()[:limit]
+            text = fp.read(limit * 2)
             if len(text) > 0:
-            app[key] = text.strip()
+                app[key] = text.strip()[:limit]
+    except Exception as e:
+        logging.error(_('{path}: {error}').format(path=f, error=str(e)))
 
 
 def _strip_and_copy_image(in_file, outpath):

tests/update.TestCase

@@ -11,6 +11,7 @@ import optparse
 import os
 import random
 import shutil
+import string
 import subprocess
 import sys
 import tempfile
@@ -1309,6 +1310,73 @@ class UpdateTest(unittest.TestCase):
         self.assertIsNotNone(fdroidserver.update.sanitize_funding_yml_entry(' WhyIncludeWhitespace '))
         self.assertIsNotNone(fdroidserver.update.sanitize_funding_yml_entry(['first', 'second']))
 
+    def test_set_localized_text_entry(self):
+        tmptestsdir = tempfile.mkdtemp(prefix=inspect.currentframe().f_code.co_name,
+                                       dir=self.tmpdir)
+        os.chdir(tmptestsdir)
+        config = dict()
+        fdroidserver.common.fill_config_defaults(config)
+        fdroidserver.update.config = config
+        fdroidserver.update.options = fdroidserver.common.options
+
+        files = {
+            'full-description.txt': 'description',
+            'short-description.txt': 'summary',
+            'title.txt': 'name',
+            'video-url.txt': 'video',
+        }
+
+        for f, key in files.items():
+            limit = config['char_limits'][key]
+            with open(f, 'w') as fp:
+                fp.write(''.join(random.choice(string.ascii_letters) for i in range(limit + 100)))
+            locale = 'ru_US'
+            app = dict()
+            fdroidserver.update._set_localized_text_entry(app, locale, key, f)
+            self.assertEqual(limit, len(app['localized'][locale][key]))
+
+            f = 'badlink-' + f
+            os.symlink('/path/to/nowhere', f)
+            app = dict()
+            fdroidserver.update._set_localized_text_entry(app, locale, key, f)
+            self.assertIsNone(app['localized'].get(locale, {}).get(key))
+
+    def test_set_author_entry(self):
+        tmptestsdir = tempfile.mkdtemp(prefix=inspect.currentframe().f_code.co_name,
+                                       dir=self.tmpdir)
+        os.chdir(tmptestsdir)
+        config = dict()
+        fdroidserver.common.fill_config_defaults(config)
+        fdroidserver.update.config = config
+        fdroidserver.update.options = fdroidserver.common.options
+
+        f = 'contact-website.txt'
+        key = 'author'
+        url = 'https://f-droid.org/'
+        limit = config['char_limits']['author']
+        with open(f, 'w') as fp:
+            fp.write(url)
+            fp.write('\n')
+        app = dict()
+        fdroidserver.update._set_author_entry(app, key, f)
+        self.assertEqual(url, app[key])
+
+        f = 'limits.txt'
+        key = 'author'
+        limit = config['char_limits']['author']
+        for key in ('authorEmail', 'authorPhone', 'authorWebSite'):
+            with open(f, 'w') as fp:
+                fp.write(''.join(random.choice(string.ascii_letters) for i in range(limit + 100)))
+            app = dict()
+            fdroidserver.update._set_author_entry(app, key, f)
+            self.assertEqual(limit, len(app[key]))
+
+        f = 'badlink.txt'
+        os.symlink('/path/to/nowhere', f)
+        app = dict()
+        fdroidserver.update._set_author_entry(app, key, f)
+        self.assertIsNone(app.get(key))
+
 
 if __name__ == "__main__":
     os.chdir(os.path.dirname(__file__))