Fix for the recursion_level bug Armin Rigo reported in sf

patch #617312, both on the trunk and the 22-maint branch.

Also added a test case, and ported the test_trace I wrote for HEAD
to 2.2.2 (with all those horrible extra 'line' events ;-).

diff --git a/Lib/test/test_trace.py b/Lib/test/test_trace.py
new file mode 100644 (file)
index 0000000..a0483eb
--- /dev/null
+++ b/Lib/test/test_trace.py
@@ -0,0 +1,216 @@
+# Testing the line trace facility.
+
+import test_support
+import unittest
+import sys
+import difflib
+
+# A very basic example.  If this fails, we're in deep trouble.
+def basic():
+    return 1
+
+basic.events = [(0, 'call'),
+                (0, 'line'),
+                (1, 'line'),
+                (1, 'return')]
+
+# Armin Rigo's failing example:
+def arigo_example():
+    x = 1
+    del x
+    while 0:
+        pass
+    x = 1
+
+arigo_example.events = [(0, 'call'),
+                        (0, 'line'),
+                        (1, 'line'),
+                        (2, 'line'),
+                        (3, 'line'),
+                        (3, 'line'),
+                        (5, 'line'),
+                        (5, 'return')]
+
+# check that lines consisting of just one instruction get traced:
+def one_instr_line():
+    x = 1
+    del x
+    x = 1
+
+one_instr_line.events = [(0, 'call'),
+                         (0, 'line'),
+                         (1, 'line'),
+                         (2, 'line'),
+                         (3, 'line'),
+                         (3, 'return')]
+
+def no_pop_tops():      # 0
+    x = 1               # 1
+    for a in range(2):  # 2
+        if a:           # 3
+            x = 1       # 4
+        else:           # 5
+            x = 1       # 6
+
+no_pop_tops.events = [(0, 'call'),
+                      (0, 'line'),
+                      (1, 'line'),
+                      (2, 'line'),
+                      (2, 'line'),
+                      (3, 'line'),
+                      (6, 'line'),
+                      (2, 'line'),
+                      (3, 'line'),
+                      (4, 'line'),
+                      (2, 'line'),
+                      (2, 'return')]
+
+def no_pop_blocks():
+    while 0:
+        bla
+    x = 1
+
+no_pop_blocks.events = [(0, 'call'),
+                        (0, 'line'),
+                        (1, 'line'),
+                        (1, 'line'),
+                        (3, 'line'),
+                        (3, 'return')]
+
+def called(): # line -3
+    x = 1
+
+def call():   # line 0
+    called()
+
+call.events = [(0, 'call'),
+               (0, 'line'),
+               (1, 'line'),
+               (-3, 'call'),
+               (-3, 'line'),
+               (-2, 'line'),
+               (-2, 'return'),
+               (1, 'return')]
+
+def raises():
+    raise Exception
+
+def test_raise():
+    try:
+        raises()
+    except Exception, exc:
+        x = 1
+
+test_raise.events = [(0, 'call'),
+                     (0, 'line'),
+                     (1, 'line'),
+                     (2, 'line'),
+                     (-3, 'call'),
+                     (-3, 'line'),
+                     (-2, 'line'),
+                     (-2, 'exception'),
+                     (2, 'exception'),
+                     (3, 'line'),
+                     (4, 'line'),
+                     (4, 'return')]
+
+def _settrace_and_return(tracefunc):
+    sys.settrace(tracefunc)
+    sys._getframe().f_back.f_trace = tracefunc
+def settrace_and_return(tracefunc):
+    _settrace_and_return(tracefunc)
+    
+settrace_and_return.events = [(1, 'return')]
+
+def _settrace_and_raise(tracefunc):
+    sys.settrace(tracefunc)
+    sys._getframe().f_back.f_trace = tracefunc
+    raise RuntimeError
+def settrace_and_raise(tracefunc):
+    try:
+        _settrace_and_raise(tracefunc)
+    except RuntimeError, exc:
+        pass
+    
+settrace_and_raise.events = [(2, 'exception'),
+                             (3, 'line'),
+                             (4, 'line'),
+                             (4, 'return')]
+
+class Tracer:
+    def __init__(self):
+        self.events = []
+    def trace(self, frame, event, arg):
+        self.events.append((frame.f_lineno, event))
+        return self.trace
+
+class TraceTestCase(unittest.TestCase):
+    def compare_events(self, line_offset, events, expected_events):
+        events = [(l - line_offset, e) for (l, e) in events]        
+        if events != expected_events:
+            self.fail(
+                "events did not match expectation:\n" +
+                "\n".join(difflib.ndiff(map(str, expected_events),
+                                        map(str, events))))
+        
+    
+    def run_test(self, func):
+        tracer = Tracer()
+        sys.settrace(tracer.trace)
+        func()
+        sys.settrace(None)
+        self.compare_events(func.func_code.co_firstlineno,
+                            tracer.events, func.events)
+
+    def run_test2(self, func):
+        tracer = Tracer()
+        func(tracer.trace)
+        sys.settrace(None)
+        self.compare_events(func.func_code.co_firstlineno,
+                            tracer.events, func.events)
+    
+    def test_1_basic(self):
+        self.run_test(basic)
+    def test_2_arigo(self):
+        self.run_test(arigo_example)
+    def test_3_one_instr(self):
+        self.run_test(one_instr_line)
+    def test_4_no_pop_blocks(self):
+        self.run_test(no_pop_blocks)
+    def test_5_no_pop_tops(self):
+        self.run_test(no_pop_tops)
+    def test_6_call(self):
+        self.run_test(call)
+    def test_7_raise(self):
+        self.run_test(test_raise)
+
+    def test_8_settrace_and_return(self):
+        self.run_test2(settrace_and_return)
+    def test_9_settrace_and_raise(self):
+        self.run_test2(settrace_and_raise)
+
+class RaisingTraceFuncTestCase(unittest.TestCase):
+    def test_it(self):
+        def tr(frame, event, arg):
+            raise ValueError # just something that isn't RuntimeError
+        def f():
+            return 1
+        try:
+            for i in xrange(sys.getrecursionlimit() + 1):
+                sys.settrace(tr)
+                try:
+                    f()
+                except ValueError:
+                    pass
+                else:
+                    self.fail("exception not thrown!")
+        except RuntimeError:
+            self.fail("recursion counter not reset")
+            
+
+def test_main():
+    test_support.run_unittest(TraceTestCase)
+    test_support.run_unittest(RaisingTraceFuncTestCase)
+
+if __name__ == "__main__":
+    test_main()