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139 lines
4.2 KiB
139 lines
4.2 KiB
"""
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Recursions are the recipe of |jedi| to conquer Python code. However, someone
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must stop recursions going mad. Some settings are here to make |jedi| stop at
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the right time. You can read more about them :ref:`here <settings-recursion>`.
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Next to :mod:`jedi.evaluate.cache` this module also makes |jedi| not
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thread-safe. Why? ``execution_recursion_decorator`` uses class variables to
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count the function calls.
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.. _settings-recursion:
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Settings
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~~~~~~~~~~
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Recursion settings are important if you don't want extremly
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recursive python code to go absolutely crazy.
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The default values are based on experiments while completing the |jedi| library
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itself (inception!). But I don't think there's any other Python library that
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uses recursion in a similarly extreme way. Completion should also be fast and
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therefore the quality might not always be maximal.
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.. autodata:: recursion_limit
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.. autodata:: total_function_execution_limit
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.. autodata:: per_function_execution_limit
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.. autodata:: per_function_recursion_limit
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"""
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from contextlib import contextmanager
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from jedi import debug
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from jedi.evaluate.base_context import NO_CONTEXTS
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recursion_limit = 15
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"""
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Like ``sys.getrecursionlimit()``, just for |jedi|.
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"""
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total_function_execution_limit = 200
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"""
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This is a hard limit of how many non-builtin functions can be executed.
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"""
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per_function_execution_limit = 6
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"""
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The maximal amount of times a specific function may be executed.
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"""
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per_function_recursion_limit = 2
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"""
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A function may not be executed more than this number of times recursively.
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"""
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class RecursionDetector(object):
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def __init__(self):
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self.pushed_nodes = []
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@contextmanager
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def execution_allowed(evaluator, node):
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"""
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A decorator to detect recursions in statements. In a recursion a statement
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at the same place, in the same module may not be executed two times.
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"""
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pushed_nodes = evaluator.recursion_detector.pushed_nodes
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if node in pushed_nodes:
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debug.warning('catched stmt recursion: %s @%s', node,
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getattr(node, 'start_pos', None))
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yield False
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else:
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try:
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pushed_nodes.append(node)
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yield True
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finally:
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pushed_nodes.pop()
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def execution_recursion_decorator(default=NO_CONTEXTS):
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def decorator(func):
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def wrapper(self, **kwargs):
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detector = self.evaluator.execution_recursion_detector
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allowed = detector.push_execution(self)
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try:
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if allowed:
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result = default
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else:
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result = func(self, **kwargs)
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finally:
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detector.pop_execution()
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return result
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return wrapper
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return decorator
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class ExecutionRecursionDetector(object):
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"""
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Catches recursions of executions.
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"""
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def __init__(self, evaluator):
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self._evaluator = evaluator
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self._recursion_level = 0
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self._parent_execution_funcs = []
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self._funcdef_execution_counts = {}
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self._execution_count = 0
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def pop_execution(self):
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self._parent_execution_funcs.pop()
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self._recursion_level -= 1
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def push_execution(self, execution):
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funcdef = execution.tree_node
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# These two will be undone in pop_execution.
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self._recursion_level += 1
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self._parent_execution_funcs.append(funcdef)
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module = execution.get_root_context()
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if module == self._evaluator.builtins_module:
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# We have control over builtins so we know they are not recursing
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# like crazy. Therefore we just let them execute always, because
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# they usually just help a lot with getting good results.
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return False
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if self._recursion_level > recursion_limit:
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return True
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if self._execution_count >= total_function_execution_limit:
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return True
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self._execution_count += 1
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if self._funcdef_execution_counts.setdefault(funcdef, 0) >= per_function_execution_limit:
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return True
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self._funcdef_execution_counts[funcdef] += 1
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if self._parent_execution_funcs.count(funcdef) > per_function_recursion_limit:
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return True
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return False
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