gh-116987: Support class code objects in inspect.findsource() (GH-117025)

Lib/inspect.py

@@ -1157,15 +1157,8 @@ 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*@)')
-        while lnum > 0:
-            try:
-                line = lines[lnum]
-            except IndexError:
-                raise OSError('lineno is out of bounds')
-            if pat.match(line):
-                break
-            lnum = lnum - 1
+        if lnum >= len(lines):
+            raise OSError('lineno is out of bounds')
         return lines, lnum
     raise OSError('could not find code object')
 

Lib/test/test_inspect/inspect_fodder2.py

@@ -310,3 +310,8 @@ else:
     class cls310:
         def g():
             pass
+
+# line 314
+class ClassWithCodeObject:
+    import sys
+    code = sys._getframe(0).f_code

Lib/test/test_inspect/test_inspect.py

@@ -983,6 +983,9 @@ class TestBuggyCases(GetSourceBase):
     def test_getsource_on_method(self):
         self.assertSourceEqual(mod2.ClassWithMethod.method, 118, 119)
 
+    def test_getsource_on_class_code_object(self):
+        self.assertSourceEqual(mod2.ClassWithCodeObject.code, 315, 317)
+
     def test_nested_func(self):
         self.assertSourceEqual(mod2.cls135.func136, 136, 139)
 

Misc/NEWS.d/next/Library/2024-03-19-19-42-25.gh-issue-116987.ZVKUH1.rst

@@ -0,0 +1 @@
+Fixed :func:`inspect.findsource` for class code objects.