From 0353c9d4fc2acf049cff81a952235fbe165213e6 Mon Sep 17 00:00:00 2001
From: Kieran Ryan <kierankilkenny@gmail.com>
Date: Sat, 13 Apr 2024 15:18:39 +0100
Subject: [PATCH] python: provide informative exception for trailing escapes in
 tables (#241)

With the Python implementation:

1. Whitespace either side of a table row is stripped.
2. The table row is passed to a function to strip and yields its cell
   values
3. Characters in each cell are iterated over to handle them
   appropriately, such as new columns (|), escape characters, etc.
4. As escape characters are typically followed by a special character
   (e.g. n, t), when an escape character is detected \\ an additional
   next call is made to grab the next character
5. As in step 1, whitespace after a trailing escape character (\\)
   would be stripped, there would not be a following character and a
   StopIteration error is raised.
---
 CHANGELOG.md                   |  5 +++--
 python/gherkin/gherkin_line.py |  2 +-
 python/test/gherkin_test.py    | 17 ++++++++++++++++-
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4d08824b7..ebd6e305c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,8 +8,9 @@ This document is formatted according to the principles of [Keep A CHANGELOG](htt
 
 ## [Unreleased]
 ### Fixed
-- Provide trailing space in Irish keywords ([#243](https://github.com/cucumber/gherkin/pull/243))
-- Tamil "And" and "But" translations should have single trailing space ([#243](https://github.com/cucumber/gherkin/pull/243))
+- [Python] Provide informative exception for trailing escapes in tables ([#241](https://github.com/cucumber/gherkin/pull/241))
+- (i18n) Provide trailing space in Irish keywords ([#243](https://github.com/cucumber/gherkin/pull/243))
+- (i18n) Tamil "And" and "But" translations should have single trailing space ([#243](https://github.com/cucumber/gherkin/pull/243))
 
 ## [28.0.0] - 2024-02-15
 ### Added
diff --git a/python/gherkin/gherkin_line.py b/python/gherkin/gherkin_line.py
index 0342d8c20..8ca945282 100644
--- a/python/gherkin/gherkin_line.py
+++ b/python/gherkin/gherkin_line.py
@@ -59,7 +59,7 @@ def split_table_cells(self, row):
                 cell = ''
                 start_col = col + 1
             elif char == '\\':
-                char = next(row)
+                char = next(row, "")
                 col += 1
                 if char == 'n':
                     cell += '\n'
diff --git a/python/test/gherkin_test.py b/python/test/gherkin_test.py
index 826f72c07..34dc99c29 100644
--- a/python/test/gherkin_test.py
+++ b/python/test/gherkin_test.py
@@ -2,7 +2,7 @@
 from gherkin.token_scanner import TokenScanner
 from gherkin.token_matcher import TokenMatcher
 from gherkin.parser import Parser
-from gherkin.errors import ParserError
+from gherkin.errors import CompositeParserException, ParserError
 import pytest
 
 
@@ -89,3 +89,18 @@ def test_change_the_default_language():
     }
 
     assert expected == feature_file
+
+@pytest.mark.parametrize("trailing_text", ["\\", "\\ "])
+def test_inconsistent_cell_count_with_trailing_escape(trailing_text):
+    feature_text = """Feature:
+    Scenario:
+      Given I have a table
+        | Name | Value |
+        | A    | """ + trailing_text
+    parser = Parser()
+
+    with pytest.raises(
+        CompositeParserException,
+        match="inconsistent cell count within the table",
+    ):
+        parser.parse(TokenScanner(feature_text))