commit 5affd23e6f42125998724787025080a24839266e
author Serhiy Storchaka <storchaka@gmail.com> Wed Apr 05 09:37:24 2017 +0300
committer GitHub <noreply@github.com> Wed Apr 05 09:37:24 2017 +0300
tree 8b7ca82362e78a32805b117d574082d512251d3c
parent 43ba8861e0ad044efafa46a7cc04e12ac5df640e

bpo-29762: More use "raise from None". (#569)

This hides unwanted implementation details from tracebacks.

Lib/lib2to3/pgen2/literals.py

diff --git a/Lib/lib2to3/pgen2/literals.py b/Lib/lib2to3/pgen2/literals.py
index 4f50d31..b9b63e6 100644
--- a/Lib/lib2to3/pgen2/literals.py
+++ b/Lib/lib2to3/pgen2/literals.py
@@ -29,12 +29,12 @@
         try:
             i = int(hexes, 16)
         except ValueError:
-            raise ValueError("invalid hex string escape ('\\%s')" % tail)
+            raise ValueError("invalid hex string escape ('\\%s')" % tail) from None
     else:
         try:
             i = int(tail, 8)
         except ValueError:
-            raise ValueError("invalid octal string escape ('\\%s')" % tail)
+            raise ValueError("invalid octal string escape ('\\%s')" % tail) from None
     return chr(i)
 
 def evalString(s):