# Testing the line trace facility.

from test import test_support

import unittest

import sys

import difflib

import gc

# A very basic example.  If this fails, we're in deep trouble.

def basic():

    return 1

basic.events = [(0, 'call'),

                (1, 'line'),

                (1, 'return')]

# Many of the tests below are tricky because they involve pass statements.

# If there is implicit control flow around a pass statement (in an except

# clause or else caluse) under what conditions do you set a line number

# following that clause?

# The entire "while 0:" statement is optimized away.  No code

# exists for it, so the line numbers skip directly from "del x"

# to "x = 1".

def arigo_example():

    x = 1

    del x

    while 0:

        pass

    x = 1

arigo_example.events = [(0, 'call'),

                        (1, 'line'),

                        (2, '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'),

                         (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'),

                      (1, 'line'),

                      (2, 'line'),

                      (3, 'line'),

                      (6, 'line'),

                      (2, 'line'),

                      (3, 'line'),

                      (4, 'line'),

                      (2, 'line'),

                      (2, 'return')]

def no_pop_blocks():

    y = 1

    while not y:

        bla

    x = 1

no_pop_blocks.events = [(0, 'call'),

                        (1, 'line'),

                        (2, 'line'),

                        (4, 'line'),

                        (4, 'return')]

def called(): # line -3

    x = 1

def call():   # line 0

    called()

call.events = [(0, 'call'),

               (1, 'line'),

               (-3, 'call'),

               (-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'),

                     (1, 'line'),

                     (2, 'line'),

                     (-3, 'call'),

                     (-2, 'line'),

                     (-2, 'exception'),

                     (-2, 'return'),

                     (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')]

# implicit return example

# This test is interesting because of the else: pass

# part of the code.  The code generate for the true

# part of the if contains a jump past the else branch.

# The compiler then generates an implicit "return None"

# Internally, the compiler visits the pass statement

# and stores its line number for use on the next instruction.

# The next instruction is the implicit return None.

def ireturn_example():

    a = 5

    b = 5

    if a == b:

        b = a+1

    else:

        pass

ireturn_example.events = [(0, 'call'),

                          (1, 'line'),

                          (2, 'line'),

                          (3, 'line'),

                          (4, 'line'),

                          (6, 'line'),

                          (6, 'return')]

# Tight loop with while(1) example (SF #765624)

def tightloop_example():

    items = range(0, 3)

    try:

        i = 0

        while 1:

            b = items[i]; i+=1

    except IndexError:

        pass

tightloop_example.events = [(0, 'call'),

                            (1, 'line'),

                            (2, 'line'),

                            (3, 'line'),

                            (4, 'line'),

                            (5, 'line'),

                            (5, 'line'),

                            (5, 'line'),

                            (5, 'line'),

                            (5, 'exception'),

                            (6, 'line'),

                            (7, 'line'),

                            (7, 'return')]

def tighterloop_example():

    items = range(1, 4)

    try:

        i = 0

        while 1: i = items[i]

    except IndexError:

        pass

tighterloop_example.events = [(0, 'call'),

                            (1, 'line'),

                            (2, 'line'),

                            (3, 'line'),

                            (4, 'line'),

                            (4, 'line'),

                            (4, 'line'),

                            (4, 'line'),

                            (4, 'exception'),

                            (5, 'line'),

                            (6, 'line'),

                            (6, 'return')]

def generator_function():

    try:

        yield True

        "continued"

    finally:

        "finally"

def generator_example():

    # any() will leave the generator before its end

    x = any(generator_function())

    # the following lines were not traced

    for x in range(10):

        y = x

generator_example.events = ([(0, 'call'),

                             (2, 'line'),

                             (-6, 'call'),

                             (-5, 'line'),

                             (-4, 'line'),

                             (-4, 'return'),

                             (-4, 'call'),

                             (-4, 'exception'),

                             (-1, 'line'),

                             (-1, 'return')] +

                            [(5, 'line'), (6, 'line')] * 10 +

                            [(5, 'line'), (5, 'return')])

class Tracer:

    def __init__(self):

        self.events = []

    def trace(self, frame, event, arg):

        self.events.append((frame.f_lineno, event))

        return self.trace

    def traceWithGenexp(self, frame, event, arg):

        (o for o in [1])

        self.events.append((frame.f_lineno, event))

        return self.trace

class TraceTestCase(unittest.TestCase):

    # Disable gc collection when tracing, otherwise the

    # deallocators may be traced as well.

    def setUp(self):

        self.using_gc = gc.isenabled()

        gc.disable()

    def tearDown(self):

        if self.using_gc:

            gc.enable()

    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([str(x) for x in expected_events],

                                        [str(x) for x in events])))

    def run_and_compare(self, func, events):

        tracer = Tracer()

        sys.settrace(tracer.trace)

        func()

        sys.settrace(None)

        self.compare_events(func.func_code.co_firstlineno,

                            tracer.events, events)

    def run_test(self, func):

        self.run_and_compare(func, 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 set_and_retrieve_none(self):

        sys.settrace(None)

        assert sys.gettrace() is None

    def set_and_retrieve_func(self):

        def fn(*args):

            pass

        sys.settrace(fn)

        try:

            assert sys.gettrace() is fn

        finally:

            sys.settrace(None)

    def test_01_basic(self):

        self.run_test(basic)

    def test_02_arigo(self):

        self.run_test(arigo_example)

    def test_03_one_instr(self):

        self.run_test(one_instr_line)

    def test_04_no_pop_blocks(self):

        self.run_test(no_pop_blocks)

    def test_05_no_pop_tops(self):

        self.run_test(no_pop_tops)

    def test_06_call(self):

        self.run_test(call)

    def test_07_raise(self):

        self.run_test(test_raise)

    def test_08_settrace_and_return(self):

        self.run_test2(settrace_and_return)

    def test_09_settrace_and_raise(self):

        self.run_test2(settrace_and_raise)

    def test_10_ireturn(self):

        self.run_test(ireturn_example)

    def test_11_tightloop(self):

        self.run_test(tightloop_example)

    def test_12_tighterloop(self):

        self.run_test(tighterloop_example)

    def test_13_genexp(self):

        self.run_test(generator_example)

        # issue1265: if the trace function contains a generator,

        # and if the traced function contains another generator

        # that is not completely exhausted, the trace stopped.

        # Worse: the 'finally' clause was not invoked.

        tracer = Tracer()

        sys.settrace(tracer.traceWithGenexp)

        generator_example()

        sys.settrace(None)

        self.compare_events(generator_example.__code__.co_firstlineno,

                            tracer.events, generator_example.events)

    def test_14_onliner_if(self):

        def onliners():

            if True: False

            else: True

            return 0

        self.run_and_compare(

            onliners,

            [(0, 'call'),

             (1, 'line'),

             (3, 'line'),

             (3, 'return')])

    def test_15_loops(self):

        # issue1750076: "while" expression is skipped by debugger

        def for_example():

            for x in range(2):

                pass

        self.run_and_compare(

            for_example,

            [(0, 'call'),

             (1, 'line'),

             (2, 'line'),

             (1, 'line'),

             (2, 'line'),

             (1, 'line'),

             (1, 'return')])

        def while_example():

            # While expression should be traced on every loop

            x = 2

            while x > 0:

                x -= 1

        self.run_and_compare(

            while_example,

            [(0, 'call'),

             (2, 'line'),

             (3, 'line'),

             (4, 'line'),

             (3, 'line'),

             (4, 'line'),

             (3, 'line'),

             (3, 'return')])

    def test_16_blank_lines(self):

        exec("def f():\n" + "\n" * 256 + "    pass")

        self.run_and_compare(

            f,

            [(0, 'call'),

             (257, 'line'),

             (257, 'return')])

class RaisingTraceFuncTestCase(unittest.TestCase):

    def trace(self, frame, event, arg):

        """A trace function that raises an exception in response to a

        specific trace event."""

        if event == self.raiseOnEvent:

            raise ValueError # just something that isn't RuntimeError

        else:

            return self.trace

    def f(self):

        """The function to trace; raises an exception if that's the case

        we're testing, so that the 'exception' trace event fires."""

        if self.raiseOnEvent == 'exception':

            x = 0

            y = 1/x

        else:

            return 1

    def run_test_for_event(self, event):

        """Tests that an exception raised in response to the given event is

        handled OK."""

        self.raiseOnEvent = event

        try:

            for i in xrange(sys.getrecursionlimit() + 1):

                sys.settrace(self.trace)

                try:

                    self.f()

                except ValueError:

                    pass

                else:

                    self.fail("exception not thrown!")

        except RuntimeError:

            self.fail("recursion counter not reset")

    # Test the handling of exceptions raised by each kind of trace event.

    def test_call(self):

        self.run_test_for_event('call')

    def test_line(self):

        self.run_test_for_event('line')

    def test_return(self):

        self.run_test_for_event('return')

    def test_exception(self):

        self.run_test_for_event('exception')

    def test_trash_stack(self):

        def f():

            for i in range(5):

                print i  # line tracing will raise an exception at this line

        def g(frame, why, extra):

            if (why == 'line' and

                frame.f_lineno == f.func_code.co_firstlineno + 2):

                raise RuntimeError, "i am crashing"

            return g

        sys.settrace(g)

        try:

            f()

        except RuntimeError:

            # the test is really that this doesn't segfault:

            import gc

            gc.collect()

        else:

            self.fail("exception not propagated")

# 'Jump' tests: assigning to frame.f_lineno within a trace function

# moves the execution position - it's how debuggers implement a Jump

# command (aka. "Set next statement").

class JumpTracer:

    """Defines a trace function that jumps from one place to another,

    with the source and destination lines of the jump being defined by

    the 'jump' property of the function under test."""

    def __init__(self, function):

        self.function = function

        self.jumpFrom = function.jump[0]

        self.jumpTo = function.jump[1]

        self.done = False

    def trace(self, frame, event, arg):

        if not self.done and frame.f_code == self.function.func_code:

            firstLine = frame.f_code.co_firstlineno

            if frame.f_lineno == firstLine + self.jumpFrom:

                # Cope with non-integer self.jumpTo (because of

                # no_jump_to_non_integers below).

                try:

                    frame.f_lineno = firstLine + self.jumpTo

                except TypeError:

                    frame.f_lineno = self.jumpTo

                self.done = True

        return self.trace

# The first set of 'jump' tests are for things that are allowed:

def jump_simple_forwards(output):

    output.append(1)

    output.append(2)

    output.append(3)

jump_simple_forwards.jump = (1, 3)

jump_simple_forwards.output = [3]

def jump_simple_backwards(output):

    output.append(1)

    output.append(2)

jump_simple_backwards.jump = (2, 1)

jump_simple_backwards.output = [1, 1, 2]

def jump_out_of_block_forwards(output):

    for i in 1, 2:

        output.append(2)

        for j in [3]:  # Also tests jumping over a block

            output.append(4)

    output.append(5)

jump_out_of_block_forwards.jump = (3, 5)

jump_out_of_block_forwards.output = [2, 5]

def jump_out_of_block_backwards(output):

    output.append(1)

    for i in [1]:

        output.append(3)

        for j in [2]:  # Also tests jumping over a block

            output.append(5)

        output.append(6)

    output.append(7)

jump_out_of_block_backwards.jump = (6, 1)

jump_out_of_block_backwards.output = [1, 3, 5, 1, 3, 5, 6, 7]

def jump_to_codeless_line(output):

    output.append(1)

    # Jumping to this line should skip to the next one.

    output.append(3)

jump_to_codeless_line.jump = (1, 2)