1 files changed, 134 insertions, 0 deletions
diff --git a/Lib/test/test_gdb/test_backtrace.py b/Lib/test/test_gdb/test_backtrace.py
new file mode 100644
index 0000000..15cbcf1
--- /dev/null
+++ b/Lib/test/test_gdb/test_backtrace.py
@@ -0,0 +1,134 @@
+import textwrap
+import unittest
+from test import support
+from test.support import python_is_optimized
+
+from .util import setup_module, DebuggerTests, CET_PROTECTION
+
+
+def setUpModule():
+    setup_module()
+
+
+class PyBtTests(DebuggerTests):
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
+    def test_bt(self):
+        'Verify that the "py-bt" command works'
+        bt = self.get_stack_trace(script=self.get_sample_script(),
+                                  cmds_after_breakpoint=['py-bt'])
+        self.assertMultilineMatches(bt,
+                                    r'''^.*
+Traceback \(most recent call first\):
+  <built-in method id of module object .*>
+  File ".*gdb_sample.py", line 10, in baz
+    id\(42\)
+  File ".*gdb_sample.py", line 7, in bar
+    baz\(a, b, c\)
+  File ".*gdb_sample.py", line 4, in foo
+    bar\(a=a, b=b, c=c\)
+  File ".*gdb_sample.py", line 12, in <module>
+    foo\(1, 2, 3\)
+''')
+
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
+    def test_bt_full(self):
+        'Verify that the "py-bt-full" command works'
+        bt = self.get_stack_trace(script=self.get_sample_script(),
+                                  cmds_after_breakpoint=['py-bt-full'])
+        self.assertMultilineMatches(bt,
+                                    r'''^.*
+#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 7, in bar \(a=1, b=2, c=3\)
+    baz\(a, b, c\)
+#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 4, in foo \(a=1, b=2, c=3\)
+    bar\(a=a, b=b, c=c\)
+#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 12, in <module> \(\)
+    foo\(1, 2, 3\)
+''')
+
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
+    @support.requires_resource('cpu')
+    def test_threads(self):
+        'Verify that "py-bt" indicates threads that are waiting for the GIL'
+        cmd = '''
+from threading import Thread
+
+class TestThread(Thread):
+    # These threads would run forever, but we'll interrupt things with the
+    # debugger
+    def run(self):
+        i = 0
+        while 1:
+             i += 1
+
+t = {}
+for i in range(4):
+   t[i] = TestThread()
+   t[i].start()
+
+# Trigger a breakpoint on the main thread
+id(42)
+
+'''
+        # Verify with "py-bt":
+        gdb_output = self.get_stack_trace(cmd,
+                                          cmds_after_breakpoint=['thread apply all py-bt'])
+        self.assertIn('Waiting for the GIL', gdb_output)
+
+        # Verify with "py-bt-full":
+        gdb_output = self.get_stack_trace(cmd,
+                                          cmds_after_breakpoint=['thread apply all py-bt-full'])
+        self.assertIn('Waiting for the GIL', gdb_output)
+
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
+    # Some older versions of gdb will fail with
+    #  "Cannot find new threads: generic error"
+    # unless we add LD_PRELOAD=PATH-TO-libpthread.so.1 as a workaround
+    def test_gc(self):
+        'Verify that "py-bt" indicates if a thread is garbage-collecting'
+        cmd = ('from gc import collect\n'
+               'id(42)\n'
+               'def foo():\n'
+               '    collect()\n'
+               'def bar():\n'
+               '    foo()\n'
+               'bar()\n')
+        # Verify with "py-bt":
+        gdb_output = self.get_stack_trace(cmd,
+                                          cmds_after_breakpoint=['break update_refs', 'continue', 'py-bt'],
+                                          )
+        self.assertIn('Garbage-collecting', gdb_output)
+
+        # Verify with "py-bt-full":
+        gdb_output = self.get_stack_trace(cmd,
+                                          cmds_after_breakpoint=['break update_refs', 'continue', 'py-bt-full'],
+                                          )
+        self.assertIn('Garbage-collecting', gdb_output)
+
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
+    def test_wrapper_call(self):
+        cmd = textwrap.dedent('''
+            class MyList(list):
+                def __init__(self):
+                    super(*[]).__init__()   # wrapper_call()
+
+            id("first break point")
+            l = MyList()
+        ''')
+        cmds_after_breakpoint = ['break wrapper_call', 'continue']
+        if CET_PROTECTION:
+            # bpo-32962: same case as in get_stack_trace():
+            # we need an additional 'next' command in order to read
+            # arguments of the innermost function of the call stack.
+            cmds_after_breakpoint.append('next')
+        cmds_after_breakpoint.append('py-bt')
+
+        # Verify with "py-bt":
+        gdb_output = self.get_stack_trace(cmd,
+                                          cmds_after_breakpoint=cmds_after_breakpoint)
+        self.assertRegex(gdb_output,
+                         r"<method-wrapper u?'__init__' of MyList object at ")