Fix exception in the ParserRuleContext.to_position extension method when the input stream is empty, release version 0.7.1

Author: alessiostalla

CHANGELOG.md

@@ -2,6 +2,19 @@
 All notable changes to this project from version 0.4.0 upwards are documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [0.7.1] – 2024-05-16
+
+### Fixed
+- `ParserRuleContext.to_position` extension method when the input stream is empty
+
+## [0.7.0] – 2023-11-21
+
+### Added
+- `Point.isBefore` method as in Kolasu
+
+### Fixed
+- Bug in the deserialization of Result
+
 ## [0.6.0] – 2023-10-10
 
 ### Added

README.md

@@ -18,18 +18,31 @@ python -m unittest discover tests
 flake8 . && flake8 tests
 ```
 
+## Testing
+
+```shell
+pytest tests
+```
+
 ## Packaging and Distribution
 
 Update version in `setup.cfg` and `pylasu/__version__.py` _(TODO do we need both?)_,
 commit and check that CI completes normally. 
 
-Ensure that you have build and twine installed:
+Let's ensure that we have build and twine installed:
 
 ```shell
 pip install build twine
 ```
 
-Then run:
+Then, check the project can be released by linting and running the test suite:
+
+```shell
+flake8 . && flake8 tests
+pytest tests
+```
+
+Finally, we can run:
 
 ```shell
 rm dist/*

pylasu/__version__.py

@@ -1 +1 @@
-__version__ = "0.7.0"
+__version__ = "0.7.1"

pylasu/parsing/parse_tree.py

@@ -43,7 +43,8 @@ def token_end_point(token: Token):
 
 @extension_method(ParserRuleContext)
 def to_position(self: ParserRuleContext, source: Source = None):
-    if self.start.start_point <= self.stop.end_point:
+    # In case of an empty input, the start token will be EOF and the end token will be None
+    if self.stop and self.start.start_point <= self.stop.end_point:
         return Position(self.start.start_point, self.stop.end_point, source)
     else:
         # In case of parse errors, sometimes ANTLR inserts nodes that end before they start

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = Pylasu
-version: 0.7.0
+version: 0.7.1
 
 [coverage:run]
 branch = True

tests/test_parse_tree.py

@@ -4,6 +4,8 @@
 
 from pylasu.model import Point
 from pylasu.parsing.parse_tree import ParseTreeOrigin, generate_nodes_classes_for_parser
+from tests.antlr_script.AntlrScriptLexer import AntlrScriptLexer
+from tests.antlr_script.AntlrScriptParser import AntlrScriptParser
 from tests.simple_lang.SimpleLangLexer import SimpleLangLexer
 from tests.simple_lang.SimpleLangParser import SimpleLangParser
 
@@ -19,6 +21,17 @@ def test_parse_tree_origin(self):
         self.assertEqual(position.start, Point(1, 0))
         self.assertEqual(position.end, Point(2, 2))
 
+    def test_empty_parse_tree_position(self):
+        lexer = AntlrScriptLexer(InputStream(""))
+        parser = AntlrScriptParser(CommonTokenStream(lexer))
+        parse_tree = parser.script()
+        self.assertIsNone(parse_tree.stop)
+        origin = ParseTreeOrigin(parse_tree)
+        position = origin.position
+        self.assertIsNotNone(position)
+        self.assertEqual(position.start, Point(1, 0))
+        self.assertEqual(position.end, Point(1, 0))
+
     def test_ast_gen(self):
         generate_nodes_classes_for_parser(SimpleLangParser, globals())
         self.assertTrue("CompilationUnit" in globals())