upstream/ipython Files · IPython/core/tests/tclass.py

Make event triggering robust to (un)registration....

Make event triggering robust to (un)registration. Event callbacks can register or unregister new callbacks for the same event while executing, and the previous triggering implementation allowed for event callbacks to be inadvertently skipped. The fix is to make a copy of the list of callbacks before executing any of them. With this change, the resulting semantics are simple: any callbacks registered before triggering are executed, and any new callbacks registered are only visible at the next triggering of the event. Note that this could potentially break existing callers who expected newly-appended callbacks were immediately executed. Fixes . Originally based on a patch by @marksandler2.

Thomas Kluyver - - Load All Authors

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      """Simple script to be run *twice*, to check reference counting bugs.

      See test_run for details."""

      from __future__ import print_function

      import sys

      # We want to ensure that while objects remain available for immediate access,

      # objects from *previous* runs of the same script get collected, to avoid

      # accumulating massive amounts of old references.

      class C(object):

          def __init__(self,name):

              self.name = name

              self.p = print

              self.flush_stdout = sys.stdout.flush

          def __del__(self):

              self.p('tclass.py: deleting object:',self.name)

              self.flush_stdout()

      try:

          name = sys.argv[1]

      except IndexError:

          pass

      else:

          if name.startswith('C'):

              c = C(name)

      #print >> sys.stderr, "ARGV:", sys.argv  # dbg

      # This next print statement is NOT debugging, we're making the check on a

      # completely separate process so we verify by capturing stdout:

      print('ARGV 1-:', sys.argv[1:])

      sys.stdout.flush()

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				"""Simple script to be run twice, to check reference counting bugs.

				See test_run for details."""

				from __future__ import print_function

				import sys

				# We want to ensure that while objects remain available for immediate access,
				# objects from previous runs of the same script get collected, to avoid
				# accumulating massive amounts of old references.
				class C(object):
				def __init__(self,name):
				self.name = name
				self.p = print
				self.flush_stdout = sys.stdout.flush

				def __del__(self):
				self.p('tclass.py: deleting object:',self.name)
				self.flush_stdout()

				try:
				name = sys.argv[1]
				except IndexError:
				pass
				else:
				if name.startswith('C'):
				c = C(name)

				#print >> sys.stderr, "ARGV:", sys.argv # dbg

				# This next print statement is NOT debugging, we're making the check on a
				# completely separate process so we verify by capturing stdout:
				print('ARGV 1-:', sys.argv[1:])
				sys.stdout.flush()