gh-137477: Fix inspect.getblock() for generator expressions

This fixes also inspect.getsourcelines() and inspect.getsource().

Author: serhiy-storchaka

Lib/inspect.py

@@ -1065,15 +1065,21 @@ def __init__(self):
 
     def tokeneater(self, type, token, srowcol, erowcol, line):
         if not self.started and not self.indecorator:
-            # skip any decorators
-            if token == "@":
-                self.indecorator = True
-            # look for the first "def", "class" or "lambda"
-            elif token in ("def", "class", "lambda"):
-                if token == "lambda":
+            if type != tokenize.INDENT:
+                # skip any decorators
+                if token == "@":
+                    self.indecorator = True
+                elif token == "async":
+                    pass
+                # look for the first "def", "class" or "lambda"
+                elif token in ("def", "class", "lambda"):
+                    if token == "lambda":
+                        self.islambda = True
+                    self.started = True
+                else:
                     self.islambda = True
-                self.started = True
-            self.passline = True    # skip to the end of the line
+                    self.started = True
+                self.passline = True    # skip to the end of the line
         elif type == tokenize.NEWLINE:
             self.passline = False   # stop skipping when a NEWLINE is seen
             self.last = srowcol[0]

Lib/test/test_inspect/inspect_fodder2.py

@@ -369,3 +369,23 @@ class dc364:
 # line 369
 dc370 = dataclasses.make_dataclass('dc370', (('x', int), ('y', int)))
 dc371 = dataclasses.make_dataclass('dc370', (('x', int), ('y', int)), module=__name__)
+
+import inspect
+import itertools
+
+# line 376
+ge377 = (
+    inspect.currentframe()
+    for i in itertools.count()
+)
+
+# line 382
+def func383():
+    # line 384
+    ge385 = (
+        inspect.currentframe()
+        for i in itertools.count()
+    )
+    return ge385
+
+pass # end of file

Lib/test/test_inspect/test_inspect.py

@@ -1189,12 +1189,18 @@ def test_nested_class_definition_inside_async_function(self):
 
         self.assertSourceEqual(run(mod2.func225), 226, 227)
         self.assertSourceEqual(mod2.cls226, 231, 235)
+        self.assertSourceEqual(mod2.cls226.func232, 232, 235)
         self.assertSourceEqual(run(mod2.cls226().func232), 233, 234)
 
     def test_class_definition_same_name_diff_methods(self):
         self.assertSourceEqual(mod2.cls296, 296, 298)
         self.assertSourceEqual(mod2.cls310, 310, 312)
 
+    def test_generator_expression(self):
+        self.assertSourceEqual(next(mod2.ge377), 377, 380)
+        self.assertSourceEqual(next(mod2.func383()), 385, 388)
+
+
 class TestNoEOL(GetSourceBase):
     def setUp(self):
         self.tempdir = TESTFN + '_dir'

Misc/NEWS.d/next/Library/2025-08-06-23-16-42.gh-issue-137477.bk6BDV.rst

@@ -0,0 +1,2 @@
+Fix :func:`inspect.getblock`, :func:`inspect.getsourcelines` and
+:func:`inspect.getsource` for generator expressions.