Disable chaining Timeout and EOF exceptions

The code works in Python 2.x and 3.x but it should be replaced by "raise
exception from other-exception" when the support for Python 2.x gets
dropped.

1 files changed, 8 insertions, 2 deletions

diff --git a/pexpect/expect.py b/pexpect/expect.py
index db376d5..34a2c93 100644
--- a/pexpect/expect.py
+++ b/pexpect/expect.py
@@ -60,7 +60,10 @@ class Expecter(object):
             msg += '\nsearcher: %s' % self.searcher
             if err is not None:
                 msg = str(err) + '\n' + msg
-            raise EOF(msg)
+
+            exc = EOF(msg)
+            exc.__cause__ = None # in Python 3.x we can use "raise exc from None"
+            raise exc
     
     def timeout(self, err=None):
         spawn = self.spawn
@@ -79,7 +82,10 @@ class Expecter(object):
             msg += '\nsearcher: %s' % self.searcher
             if err is not None:
                 msg = str(err) + '\n' + msg
-            raise TIMEOUT(msg)
+
+            exc = TIMEOUT(msg)
+            exc.__cause__ = None    # in Python 3.x we can use "raise exc from None"
+            raise exc
 
     def errored(self):
         spawn = self.spawn