Redownload a tarball if it exists but is 0 bytes long

This is a safety measure. Commit
8bddb0996c44ce8ce989359a7b4c9ff102466ef2 should mean that this can't
happen, but 'lorry' runs unattended so we really don't want it to break.

1 files changed, 7 insertions, 1 deletions

diff --git a/lorry b/lorry
index 77fc9c8..d28d064 100755
--- a/lorry
+++ b/lorry
@@ -30,6 +30,12 @@ __version__ = '0.0'
 
 lorry_path = os.path.realpath(__file__)
 
+
+def file_missing_or_empty(filename):
+    ''' A more comprehensive alternative to os.path.exists(). '''
+    return (not os.path.isfile(filename)) or (os.path.getsize(filename) <= 0)
+
+
 def quote_url(url):
     ''' Convert URIs to strings that only contain digits, letters, % and _.
 
@@ -475,7 +481,7 @@ class Lorry(cliapp.Application):
         basename = os.path.basename(url_path)
         tardest = os.path.join(dirname, basename)
         self.progress('.. checking if we need to fetch %s' % basename)
-        if not os.path.exists(tardest):
+        if file_missing_or_empty(tardest):
             self.progress('.. attempting to fetch.')
             try:
                 with open(tardest, 'w') as tarfile: