bitbake/fetch: if mirror fetching fails, ensure exception is raised

We catch any exception raised by the fetchers go() method and attempt to work
around it by trying any (post) mirrors which are configured. However, should
the mirrors fail the exception is lost and the fetch is assumed to have
completed successfully.

Instead, save the exception and if the local file does not exist after trying
the mirrors re-raise the exception.

Fixes [BUGID #362]

Signed-off-by: Joshua Lock <josh@linux.intel.com>

bitbake/lib/bb/fetch/__init__.py

@@ -272,10 +272,12 @@ def go(d, urls = None):
             try:
                 m.go(u, ud, d)
                 localpath = ud.localpath
-            except:
+            except FetchError:
                 # Finally, try fetching uri, u, from MIRRORS
                 mirrors = [ i.split() for i in (bb.data.getVar('MIRRORS', d, 1) or "").split('\n') if i ]
                 localpath = try_mirrors (d, u, mirrors)
+                if not localpath or not os.path.exists(localpath):
+                    raise FetchError("Unable to fetch URL %s from any source." % u)
 
         if localpath:
             ud.localpath = localpath