Only download mirror list when needed

src/bin/sage-download-file

@@ -335,7 +335,7 @@ class Tarball(object):
         sha1 = self._compute_sha1()
         return sha1 == self.sha1
 
-    def download(self, mirror_list):
+    def download(self):
         """
         Download the tarball to the upstream directory.
         """
@@ -350,7 +350,8 @@ class Tarball(object):
                       .format(destination=destination))
                 os.remove(destination)
         successful_download = False
-        for mirror in mirror_list:
+        print('Attempting to download package {0} from mirrors'.format(self.filename))
+        for mirror in MirrorList():
             url = mirror + '/'.join(['spkg', 'upstream', self.package, self.filename])
             print(url)
             try:
@@ -415,8 +416,7 @@ if __name__ == '__main__':
         http_download(url, destination, progress=progress, ignore_errors=True)
     else:
         # url is a tarball name
-        mirror_list = MirrorList()
         tarball = Tarball(url)
-        tarball.download(mirror_list)
+        tarball.download()
         if destination is not None:
             tarball.save_as(destination)

src/bin/sage-spkg

@@ -57,6 +57,9 @@
 # Bail on errors
 set -e
 
+# This script is called in a pipe, do not let Python buffer stdout
+export PYTHONUNBUFFERED=yes
+
 # Avoid surprises with character ranges [a-z] in regular expressions
 export LC_ALL=C
 
@@ -302,19 +305,14 @@ fi
 
 # If we haven't found the package yet, we must download it
 if [ ! -f "$PKG_SRC" ]; then
-    if [ $INFO -eq 0 ]; then
-        echo "Attempting to download package $PKG_NAME"
-    else
-        echo "Attempting to get on-line info for package $PKG_NAME"
-    fi
-
     if [ -n "$PKG_NAME_UPSTREAM" ]; then
         # This is the new-style package way of downloading the tarball
         sage-download-file $PKG_NAME_UPSTREAM
         PKG_SRC="$SAGE_DISTFILES/$PKG_NAME_UPSTREAM"
     else
         # Handle all the legacy cruft. This branch can be deleted once
         # we get rid of old-style spkgs
+        echo "Attempting to get on-line info for package $PKG_NAME"
 
         # Reduce everything to case 4: full URL.
         if [ -n "$PKG_HAS_PATH" ]; then