Description: Don't download SHA256 if it's already available locally
 In Debian we provide the stage0 tarballs as a separate component so that the
 buildds don't need to access the network during the build.
Author: Ximin Luo <infinity0@debian.org>
Forwarded: not-needed
---
This patch header follows DEP-3: http://dep.debian.net/deps/dep3/
--- a/src/bootstrap/bootstrap.py
+++ b/src/bootstrap/bootstrap.py
@@ -24,16 +24,18 @@
 from time import time
 
 
-def get(url, path, verbose=False):
+def get(url, path, verbose=False, use_local_hash_if_present=True):
     suffix = '.sha256'
     sha_url = url + suffix
     with tempfile.NamedTemporaryFile(delete=False) as temp_file:
         temp_path = temp_file.name
-    with tempfile.NamedTemporaryFile(suffix=suffix, delete=False) as sha_file:
-        sha_path = sha_file.name
+    sha_path = path + suffix
 
     try:
-        download(sha_path, sha_url, False, verbose)
+        if use_local_hash_if_present and os.path.exists(sha_path):
+            print("using already-download file " + sha_path)
+        else:
+            download(sha_path, sha_url, False, verbose)
         if os.path.exists(path):
             if verify(path, sha_path, False):
                 if verbose:
@@ -51,7 +53,6 @@
             print("moving {} to {}".format(temp_path, path))
         shutil.move(temp_path, path)
     finally:
-        delete_if_present(sha_path, verbose)
         delete_if_present(temp_path, verbose)
 
 
@@ -373,7 +374,7 @@
 
         url = "{}/dist/{}".format(self._download_url, self.date)
         tarball = os.path.join(rustc_cache, filename)
-        if not os.path.exists(tarball):
+        if True:
             get("{}/{}".format(url, filename), tarball, verbose=self.verbose)
         unpack(tarball, self.bin_root(), match=pattern, verbose=self.verbose)