Issue #4050: inspect.findsource/getsource now raise an IOError if the 'source'
file is a binary.  Patch by Brodie Rao, test by Daniel Diniz.
diff --git a/Lib/inspect.py b/Lib/inspect.py
index 1453f3b..3305c8d 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -523,7 +523,9 @@
     or code object.  The source code is returned as a list of all the lines
     in the file and the line number indexes a line in that list.  An IOError
     is raised if the source code cannot be retrieved."""
-    file = getsourcefile(object) or getfile(object)
+    file = getsourcefile(object)
+    if not file:
+        raise IOError('source code not available')
     module = getmodule(object, file)
     if module:
         lines = linecache.getlines(file, module.__dict__)
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 7312cac..5c41433 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -9,6 +9,9 @@
 from test import inspect_fodder as mod
 from test import inspect_fodder2 as mod2
 
+# C module for test_findsource_binary
+import time
+
 # Functions tested in this suite:
 # ismodule, isclass, ismethod, isfunction, istraceback, isframe, iscode,
 # isbuiltin, isroutine, isgenerator, isgeneratorfunction, getmembers,
@@ -329,6 +332,10 @@
     def test_method_in_dynamic_class(self):
         self.assertSourceEqual(mod2.method_in_dynamic_class, 95, 97)
 
+    def test_findsource_binary(self):
+        self.assertRaises(IOError, inspect.getsource, time)
+        self.assertRaises(IOError, inspect.findsource, time)
+
 # Helper for testing classify_class_attrs.
 def attrs_wo_objs(cls):
     return [t[:3] for t in inspect.classify_class_attrs(cls)]
diff --git a/Misc/ACKS b/Misc/ACKS
index 9db9f61..5cae037 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -171,6 +171,7 @@
 Toby Dickenson
 Mark Dickinson
 Jack Diederich
+Daniel Diniz
 Yves Dionne
 Daniel Dittmar
 Jaromir Dolecek
@@ -577,6 +578,7 @@
 Brian Quinlan
 Anders Qvist
 Burton Radons
+Brodie Rao
 Antti Rasinen
 Eric Raymond
 Edward K. Ream
diff --git a/Misc/NEWS b/Misc/NEWS
index b717729..2203621 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -293,6 +293,9 @@
 Library
 -------
 
+- Issue #4050: inspect.findsource/getsource now raise an IOError if the 'source'
+  file is a binary.  Patch by Brodie Rao, tests by Daniel Diniz.
+
 - Issue #5977: distutils build_ext.get_outputs was not taking into account the
   inplace option. Initial patch by kxroberto.