gh-118465: Add __firstlineno__ attribute to class (GH-118475)

It is set by compiler with the line number of the first line of
the class definition.

4 files changed, 29 insertions, 7 deletions

diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index 484d72e..1f4368b 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -1958,7 +1958,10 @@ class TestSourcePositions(unittest.TestCase):
 
     def test_load_super_attr(self):
         source = "class C:\n  def __init__(self):\n    super().__init__()"
-        code = compile(source, "<test>", "exec").co_consts[0].co_consts[1]
+        for const in compile(source, "<test>", "exec").co_consts[0].co_consts:
+            if isinstance(const, types.CodeType):
+                code = const
+                break
         self.assertOpcodeSourcePositionIs(
             code, "LOAD_GLOBAL", line=3, end_line=3, column=4, end_column=9
         )
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 93f66a7..18144c8 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -5088,7 +5088,8 @@ class DictProxyTests(unittest.TestCase):
         self.assertNotIsInstance(it, list)
         keys = list(it)
         keys.sort()
-        self.assertEqual(keys, ['__dict__', '__doc__', '__module__',
+        self.assertEqual(keys, ['__dict__', '__doc__', '__firstlineno__',
+                                '__module__',
                                 '__static_attributes__', '__weakref__',
                                 'meth'])
 
@@ -5099,7 +5100,7 @@ class DictProxyTests(unittest.TestCase):
         it = self.C.__dict__.values()
         self.assertNotIsInstance(it, list)
         values = list(it)
-        self.assertEqual(len(values), 6)
+        self.assertEqual(len(values), 7)
 
     @unittest.skipIf(hasattr(sys, 'gettrace') and sys.gettrace(),
                         'trace function introduces __local__')
@@ -5109,7 +5110,8 @@ class DictProxyTests(unittest.TestCase):
         self.assertNotIsInstance(it, list)
         keys = [item[0] for item in it]
         keys.sort()
-        self.assertEqual(keys, ['__dict__', '__doc__', '__module__',
+        self.assertEqual(keys, ['__dict__', '__doc__', '__firstlineno__',
+                                '__module__',
                                 '__static_attributes__', '__weakref__',
                                 'meth'])
 
diff --git a/Lib/test/test_inspect/test_inspect.py b/Lib/test/test_inspect/test_inspect.py
index d122403..82e466e 100644
--- a/Lib/test/test_inspect/test_inspect.py
+++ b/Lib/test/test_inspect/test_inspect.py
@@ -817,6 +817,21 @@ class TestRetrievingSourceCode(GetSourceBase):
     def test_getsource_on_code_object(self):
         self.assertSourceEqual(mod.eggs.__code__, 12, 18)
 
+    def test_getsource_on_generated_class(self):
+        A = type('A', (), {})
+        self.assertEqual(inspect.getsourcefile(A), __file__)
+        self.assertEqual(inspect.getfile(A), __file__)
+        self.assertIs(inspect.getmodule(A), sys.modules[__name__])
+        self.assertRaises(OSError, inspect.getsource, A)
+        self.assertRaises(OSError, inspect.getsourcelines, A)
+        self.assertIsNone(inspect.getcomments(A))
+
+    def test_getsource_on_class_without_firstlineno(self):
+        __firstlineno__ = 1
+        class C:
+            nonlocal __firstlineno__
+        self.assertRaises(OSError, inspect.getsource, C)
+
 class TestGetsourceInteractive(unittest.TestCase):
     def test_getclasses_interactive(self):
         # bpo-44648: simulate a REPL session;
diff --git a/Lib/test/test_metaclass.py b/Lib/test/test_metaclass.py
index 70f9c5d..b37b7de 100644
--- a/Lib/test/test_metaclass.py
+++ b/Lib/test/test_metaclass.py
@@ -164,6 +164,7 @@ Use a __prepare__ method that returns an instrumented dict.
     ...
     d['__module__'] = 'test.test_metaclass'
     d['__qualname__'] = 'C'
+    d['__firstlineno__'] = 1
     d['foo'] = 4
     d['foo'] = 42
     d['bar'] = 123
@@ -183,12 +184,12 @@ Use a metaclass that doesn't derive from type.
     ...     b = 24
     ...
     meta: C ()
-    ns: [('__module__', 'test.test_metaclass'), ('__qualname__', 'C'), ('__static_attributes__', ()), ('a', 42), ('b', 24)]
+    ns: [('__firstlineno__', 1), ('__module__', 'test.test_metaclass'), ('__qualname__', 'C'), ('__static_attributes__', ()), ('a', 42), ('b', 24)]
     kw: []
     >>> type(C) is dict
     True
     >>> print(sorted(C.items()))
-    [('__module__', 'test.test_metaclass'), ('__qualname__', 'C'), ('__static_attributes__', ()), ('a', 42), ('b', 24)]
+    [('__firstlineno__', 1), ('__module__', 'test.test_metaclass'), ('__qualname__', 'C'), ('__static_attributes__', ()), ('a', 42), ('b', 24)]
     >>>
 
 And again, with a __prepare__ attribute.
@@ -206,12 +207,13 @@ And again, with a __prepare__ attribute.
     prepare: C () [('other', 'booh')]
     d['__module__'] = 'test.test_metaclass'
     d['__qualname__'] = 'C'
+    d['__firstlineno__'] = 1
     d['a'] = 1
     d['a'] = 2
     d['b'] = 3
     d['__static_attributes__'] = ()
     meta: C ()
-    ns: [('__module__', 'test.test_metaclass'), ('__qualname__', 'C'), ('__static_attributes__', ()), ('a', 2), ('b', 3)]
+    ns: [('__firstlineno__', 1), ('__module__', 'test.test_metaclass'), ('__qualname__', 'C'), ('__static_attributes__', ()), ('a', 2), ('b', 3)]
     kw: [('other', 'booh')]
     >>>