gh-79282: Fix inspect.findsource breaking on class frame objects

Lib/inspect.py

@@ -826,7 +826,7 @@ def findsource(object):
         if not hasattr(object, 'co_firstlineno'):
             raise OSError('could not find function definition')
         lnum = object.co_firstlineno - 1
-        pat = re.compile(r'^(\s*def\s)|(\s*async\s+def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*@)')
+        pat = re.compile(r'^(\s*def\s)|(\s*async\s+def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*class\s)|^(\s*@)')
         while lnum > 0:
             if pat.match(lines[lnum]): break
             lnum = lnum - 1

Lib/test/inspect_fodder.py

@@ -80,3 +80,24 @@ async def lobbest(grenade):
     raise Exception()
 except:
     tb = sys.exc_info()[2]
+
+# line 84
+def extra_c():
+    pass
+class C:
+    def func(self):
+        pass
+    fr = inspect.currentframe()
+
+# line 92
+extra_b = 1
+class B:
+    def func(self):
+        pass
+    fr = inspect.currentframe()
+
+# line 99
+class A:
+    def func(self):
+        pass
+    fr = inspect.currentframe()

Lib/test/test_inspect.py

@@ -375,13 +375,20 @@ def assertSourceEqual(self, obj, top, bottom):
         self.assertEqual(inspect.getsource(obj),
                          self.sourcerange(top, bottom))
 
+    def assertNotSourceEqual(self, obj, top, bottom):
+        self.assertNotEqual(inspect.getsource(obj),
+                            self.sourcerange(top, bottom))
+
 class TestRetrievingSourceCode(GetSourceBase):
     fodderModule = mod
 
     def test_getclasses(self):
         classes = inspect.getmembers(mod, inspect.isclass)
         self.assertEqual(classes,
-                         [('FesteringGob', mod.FesteringGob),
+                         [('A', mod.A),
+                          ('B', mod.B),
+                          ('C', mod.C),
+                          ('FesteringGob', mod.FesteringGob),
                           ('MalodorousPervert', mod.MalodorousPervert),
                           ('ParrotDroppings', mod.ParrotDroppings),
                           ('StupidGit', mod.StupidGit),
@@ -390,7 +397,10 @@ def test_getclasses(self):
         tree = inspect.getclasstree([cls[1] for cls in classes])
         self.assertEqual(tree,
                          [(object, ()),
-                          [(mod.ParrotDroppings, (object,)),
+                          [(mod.A, (object,)),
+                           (mod.B, (object,)),
+                           (mod.C, (object,)),
+                           (mod.ParrotDroppings, (object,)),
                            [(mod.FesteringGob, (mod.MalodorousPervert,
                                                    mod.ParrotDroppings))
                             ],
@@ -405,7 +415,10 @@ def test_getclasses(self):
         tree = inspect.getclasstree([cls[1] for cls in classes], True)
         self.assertEqual(tree,
                          [(object, ()),
-                          [(mod.ParrotDroppings, (object,)),
+                          [(mod.A, (object,)),
+                           (mod.B, (object,)),
+                           (mod.C, (object,)),
+                           (mod.ParrotDroppings, (object,)),
                            (mod.StupidGit, (object,)),
                            [(mod.MalodorousPervert, (mod.StupidGit,)),
                             [(mod.FesteringGob, (mod.MalodorousPervert,
@@ -418,6 +431,7 @@ def test_getclasses(self):
     def test_getfunctions(self):
         functions = inspect.getmembers(mod, inspect.isfunction)
         self.assertEqual(functions, [('eggs', mod.eggs),
+                                     ('extra_c', mod.extra_c),
                                      ('lobbest', mod.lobbest),
                                      ('spam', mod.spam)])
 
@@ -552,7 +566,7 @@ def monkey(filename, module_globals=None):
     def test_getsource_on_code_object(self):
         self.assertSourceEqual(mod.eggs.__code__, 12, 18)
 
-class TestGettingSourceOfToplevelFrames(GetSourceBase):
+class TestGettingSourceOfFrames(GetSourceBase):
     fodderModule = mod
 
     def test_range_toplevel_frame(self):
@@ -562,6 +576,14 @@ def test_range_toplevel_frame(self):
     def test_range_traceback_toplevel_frame(self):
         self.assertSourceEqual(mod.tb, 1, None)
 
+    def test_class_frame(self):
+        self.assertSourceEqual(mod.A.fr, 100, 103)
+        self.assertNotSourceEqual(mod.A.fr, 85, 86)
+        self.assertSourceEqual(mod.B.fr, 94, 97)
+        self.assertNotSourceEqual(mod.B.fr, 85, 86)
+        self.assertSourceEqual(mod.C.fr, 87, 90)
+        self.assertNotSourceEqual(mod.C.fr, 85, 86)
+
 class TestDecorators(GetSourceBase):
     fodderModule = mod2
 
@@ -676,7 +698,6 @@ def test_getsource_on_method(self):
     def test_nested_func(self):
         self.assertSourceEqual(mod2.cls135.func136, 136, 139)
 
-
 class TestNoEOL(GetSourceBase):
     def setUp(self):
         self.tempdir = TESTFN + '_dir'
@@ -3905,7 +3926,7 @@ def test_main():
         TestBoundArguments, TestSignaturePrivateHelpers,
         TestSignatureDefinitions, TestIsDataDescriptor,
         TestGetClosureVars, TestUnwrap, TestMain, TestReload,
-        TestGetCoroutineState, TestGettingSourceOfToplevelFrames
+        TestGetCoroutineState, TestGettingSourceOfFrames
     )
 
 if __name__ == "__main__":

Misc/NEWS.d/next/Library/2018-10-29-04-14-58.bpo-35101.xImh8d.rst

@@ -0,0 +1,2 @@
+Fix inspect.findsource incorrectly returning the line number of the first
+function above any given class frame objects.