Fix get_word_before_cursor behavior

src/prompt_toolkit/document.py

@@ -457,12 +457,10 @@ def get_word_before_cursor(
     def _is_word_before_cursor_complete(
         self, WORD: bool = False, pattern: Pattern[str] | None = None
     ) -> bool:
+        if not self.text_before_cursor == "" or self.text_before_cursor[-1:].isspace():
+            return True
         if pattern:
             return self.find_start_of_previous_word(WORD=WORD, pattern=pattern) is None
-        else:
-            return (
-                self.text_before_cursor == "" or self.text_before_cursor[-1:].isspace()
-            )
 
     def find_start_of_previous_word(
         self, count: int = 1, WORD: bool = False, pattern: Pattern[str] | None = None

tests/test_document.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import pytest
+import re
 
 from prompt_toolkit.document import Document
 
@@ -67,3 +68,13 @@ def test_translate_index_to_position(document):
 def test_is_cursor_at_the_end(document):
     assert Document("hello", 5).is_cursor_at_the_end
     assert not Document("hello", 4).is_cursor_at_the_end
+
+
+def test_get_word_before_cursor_with_whitespace_and_pattern():
+    text = "foobar "
+    document = Document(text=text, cursor_position=len(text))
+
+    assert document.get_word_before_cursor() == ""
+
+    _FIND_WORD_RE = re.compile(r"([a-zA-Z0-9_]+|[^a-zA-Z0-9_\s]+)")
+    assert document.get_word_before_cursor(pattern=_FIND_WORD_RE) == ""