From d0f83664b84cd8437eabb179df56c5b57f8610df Mon Sep 17 00:00:00 2001
From: sf-wind <feisun@fb.com>
Date: Wed, 16 Jan 2019 21:31:58 -0800
Subject: [PATCH] Avoid runtime exception when file doesn't exist (#2441)

* Avoid runtime exception when file doesn't exist

* Update the check based on feedback

* Revert the old fix
---
 python/tvm/autotvm/tophub.py | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/python/tvm/autotvm/tophub.py b/python/tvm/autotvm/tophub.py
index b611f3cee054..9ec9becc7245 100644
--- a/python/tvm/autotvm/tophub.py
+++ b/python/tvm/autotvm/tophub.py
@@ -77,7 +77,8 @@ def context(target, extra_files=None):
         for name in possible_names:
             name = _alias(name)
             if name in all_packages:
-                check_backend(name)
+                if not check_backend(name):
+                    continue
 
                 filename = "%s_%s.log" % (name, PACKAGE_VERSION[name])
                 best_context.load(os.path.join(AUTOTVM_TOPHUB_ROOT_PATH, filename))
@@ -98,6 +99,11 @@ def check_backend(backend):
     ----------
     backend: str
         The name of backend.
+
+    Returns
+    ----------
+    success: bool
+        Whether the check is successful.
     """
     backend = _alias(backend)
     assert backend in PACKAGE_VERSION, 'Cannot find backend "%s" in TopHub' % backend
@@ -105,7 +111,7 @@ def check_backend(backend):
     version = PACKAGE_VERSION[backend]
     package_name = "%s_%s.log" % (backend, version)
     if os.path.isfile(os.path.join(AUTOTVM_TOPHUB_ROOT_PATH, package_name)):
-        return
+        return True
 
     if sys.version_info >= (3,):
         import urllib.request as urllib2
@@ -113,8 +119,10 @@ def check_backend(backend):
         import urllib2
     try:
         download_package(package_name)
+        return True
     except urllib2.URLError as e:
         logging.warning("Failed to download tophub package for %s: %s", backend, e)
+        return False
 
 
 def download_package(package_name):