From cf1a9ac320717f5db042130eb995e42f1e3d3a6c Mon Sep 17 00:00:00 2001
From: Zev Benjamin <zev@dropbox.com>
Date: Thu, 24 Sep 2015 15:08:48 -0700
Subject: Ensure each generated function has a unique filename

Some profilers (such as cProfile) depend on the tuple of (<filename>,
<definition line>, <function name>) being unique.  If the filenames of generated
functions are all the same, such profilers can produce incorrect profiles.
---
 src/decorator.py  | 11 ++++++++++-
 src/tests/test.py | 29 ++++++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/decorator.py b/src/decorator.py
index 7a8b232..9264998 100644
--- a/src/decorator.py
+++ b/src/decorator.py
@@ -87,6 +87,10 @@ class FunctionMaker(object):
     It has attributes name, doc, module, signature, defaults, dict and
     methods update and make.
     """
+
+    # Atomic get-and-increment provided by the GIL
+    _compile_count = itertools.count()
+
     def __init__(self, func=None, name=None, signature=None,
                  defaults=None, doc=None, module=None, funcdict=None):
         self.shortsignature = signature
@@ -176,8 +180,13 @@ class FunctionMaker(object):
                 raise NameError('%s is overridden in\n%s' % (n, src))
         if not src.endswith('\n'):  # add a newline just for safety
             src += '\n'  # this is needed in old versions of Python
+
+        # Ensure each generated function has a unique filename for profilers
+        # (such as cProfile) that depend on the tuple of (<filename>,
+        # <definition line>, <function name>) being unique.
+        filename = '<decorator-gen-%d>' % (next(self._compile_count),)
         try:
-            code = compile(src, '<string>', 'single')
+            code = compile(src, filename, 'single')
             exec(code, evaldict)
         except:
             print('Error in generated code:', file=sys.stderr)
diff --git a/src/tests/test.py b/src/tests/test.py
index 45a9b9b..ab65dfa 100644
--- a/src/tests/test.py
+++ b/src/tests/test.py
@@ -6,7 +6,7 @@ import decimal
 import inspect
 import functools
 import collections
-from decorator import dispatch_on, contextmanager
+from decorator import dispatch_on, contextmanager, decorator
 try:
     from . import documentation as doc
 except (SystemError, ValueError):
@@ -52,6 +52,33 @@ class ExtraTestCase(unittest.TestCase):
             sig = inspect.signature(doc.f1)
             self.assertEqual(str(sig), '(x)')
 
+    def test_unique_filenames(self):
+        @decorator
+        def d1(f, *args, **kwargs):
+            return f(*args, **kwargs)
+
+        @decorator
+        def d2(f, *args, **kwargs):
+            return f(*args, **kwargs)
+
+        @d1
+        def f1(x, y, z):
+            pass
+
+        @d2
+        def f2(x, y, z):
+            pass
+
+        f1_orig = f1
+
+        @d1
+        def f1(x, y, z):
+            pass
+
+        self.assertNotEqual(d1.__code__.co_filename, d2.__code__.co_filename)
+        self.assertNotEqual(f1.__code__.co_filename, f2.__code__.co_filename)
+        self.assertNotEqual(f1_orig.__code__.co_filename, f1.__code__.co_filename)
+
 # ################### test dispatch_on ############################# #
 # adapted from test_functools in Python 3.5
 singledispatch = dispatch_on('obj')
-- 
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