fix: don't overwrite tracebacklimit when parsing

This commit updates the __call__ method of both DomainParser and ProblemParser classes in such a way that sys.tracebacklimit is not overwritten to 'None' if it has been already set by the caller.

pddl/helpers/base.py

@@ -13,6 +13,7 @@
 """Helper functions."""
 
 import re
+import sys
 from pathlib import Path
 from typing import (
     AbstractSet,
@@ -25,8 +26,11 @@
     Sequence,
     Set,
     Type,
+    TypeVar,
 )
 
+from lark import Lark, Transformer
+
 
 def _get_current_path() -> Path:
     """Get the path to the file where the function is called."""
@@ -191,3 +195,30 @@ def find_cycle(graph: Dict[str, Optional[AbstractSet[str]]]) -> Optional[Sequenc
                         stack.append((neighbor, path + [current]))
 
     return None
+
+
+T = TypeVar("T")
+
+
+def call_parser(text: str, parser: Lark, transformer: Transformer[Any, T]) -> T:
+    """
+    Parse a text with a Lark parser and transformer.
+
+    To produce a better traceback in case of an error, the function will temporarily overwrite the sys.tracebacklimit
+    value of the current interpreter.
+
+    :param text: the text to parse
+    :param parser: the Lark parser object
+    :param transformer: the Lark transformer object
+    :return: the object returned by the parser
+    """
+    old_tracebacklimit = getattr(sys, "tracebacklimit", None)
+    try:
+        sys.tracebacklimit = 0  # noqa
+        tree = parser.parse(text)
+        sys.tracebacklimit = None  # type: ignore
+        result = transformer.transform(tree)
+    finally:
+        if old_tracebacklimit is not None:
+            sys.tracebacklimit = old_tracebacklimit
+    return result

pddl/parser/domain.py

@@ -11,7 +11,6 @@
 #
 
 """Implementation of the PDDL domain parser."""
-import sys
 from typing import Any, Dict, Optional, Set, Tuple
 
 from lark import Lark, ParseError, Transformer
@@ -20,7 +19,7 @@
 from pddl.core import Domain
 from pddl.custom_types import name
 from pddl.exceptions import PDDLMissingRequirementError, PDDLParsingError
-from pddl.helpers.base import assert_
+from pddl.helpers.base import assert_, call_parser
 from pddl.logic.base import And, ExistsCondition, ForallCondition, Imply, Not, OneOf, Or
 from pddl.logic.effects import AndEffect, Forall, When
 from pddl.logic.functions import Assign, Decrease, Divide
@@ -462,8 +461,4 @@ def __init__(self):
 
     def __call__(self, text: str) -> Domain:
         """Call."""
-        sys.tracebacklimit = 0  # noqa
-        tree = self._parser.parse(text)
-        sys.tracebacklimit = None  # type: ignore
-        formula = self._transformer.transform(tree)
-        return formula
+        return call_parser(text, self._parser, self._transformer)

pddl/parser/problem.py

@@ -11,14 +11,13 @@
 #
 
 """Implementation of the PDDL problem parser."""
-import sys
 from typing import Any, Dict
 
 from lark import Lark, ParseError, Transformer
 
 from pddl.core import Problem
 from pddl.exceptions import PDDLParsingError
-from pddl.helpers.base import assert_
+from pddl.helpers.base import assert_, call_parser
 from pddl.logic.base import And, Not
 from pddl.logic.functions import Divide
 from pddl.logic.functions import EqualTo as FunctionEqualTo
@@ -242,10 +241,6 @@ def __init__(self):
             _problem_parser_lark, parser="lalr", import_paths=[PARSERS_DIRECTORY]
         )
 
-    def __call__(self, text) -> Problem:
+    def __call__(self, text: str) -> Problem:
         """Call."""
-        sys.tracebacklimit = 0  # noqa
-        tree = self._parser.parse(text)
-        sys.tracebacklimit = None  # type: ignore
-        formula = self._transformer.transform(tree)
-        return formula
+        return call_parser(text, self._parser, self._transformer)