Identify bracket cursor highlighting in source coordinates

src/prompt_toolkit/layout/processors.py

@@ -420,11 +420,15 @@ def apply_transformation(
         if positions:
             for row, col in positions:
                 if row == lineno:
+                    on_cursor = (
+                        row == document.cursor_position_row
+                        and col == document.cursor_position_col
+                    )
                     col = source_to_display(col)
                     fragments = explode_text_fragments(fragments)
                     style, text, *_ = fragments[col]
 
-                    if col == document.cursor_position_col:
+                    if on_cursor:
                         style += " class:matching-bracket.cursor "
                     else:
                         style += " class:matching-bracket.other "

tests/test_bracket_processor.py

@@ -0,0 +1,62 @@
+from __future__ import annotations
+
+import pytest
+
+from prompt_toolkit.document import Document
+from prompt_toolkit.layout.controls import BufferControl
+from prompt_toolkit.layout.processors import (
+    HighlightMatchingBracketProcessor,
+    TransformationInput,
+)
+
+
+@pytest.mark.parametrize("cursor_position", [0, 2])
+@pytest.mark.parametrize("prefix", ["", ">> "])
+def test_matching_bracket_cursor_style_uses_source_row_and_column(
+    cursor_position, prefix
+):
+    document = Document("(\n)", cursor_position=cursor_position)
+    processor = HighlightMatchingBracketProcessor()
+    for lineno, line in enumerate(document.lines):
+        result = processor.apply_transformation(
+            TransformationInput(
+                buffer_control=BufferControl(),
+                document=document,
+                lineno=lineno,
+                source_to_display=lambda i: i + len(prefix),
+                fragments=[("", prefix + line)],
+                width=80,
+                height=24,
+            )
+        )
+        style = result.fragments[len(prefix)][0]
+        if lineno == document.cursor_position_row:
+            assert "class:matching-bracket.cursor" in style
+            assert "class:matching-bracket.other" not in style
+        else:
+            assert "class:matching-bracket.other" in style
+            assert "class:matching-bracket.cursor" not in style
+
+
+@pytest.mark.parametrize("text", ["()", "(\n)"])
+@pytest.mark.parametrize("prefix", ["", ">> "])
+def test_matching_brackets_after_closing_bracket_keep_other_style(text, prefix):
+    document = Document(text, cursor_position=len(text))
+    processor = HighlightMatchingBracketProcessor()
+    styles = []
+    for lineno, line in enumerate(document.lines):
+        result = processor.apply_transformation(
+            TransformationInput(
+                buffer_control=BufferControl(),
+                document=document,
+                lineno=lineno,
+                source_to_display=lambda i: i + len(prefix),
+                fragments=[("", prefix + line)],
+                width=80,
+                height=24,
+            )
+        )
+        styles.extend(style for style, char in result.fragments if char in "()")
+    assert len(styles) == 2
+    assert all("class:matching-bracket.other" in style for style in styles)
+    assert all("class:matching-bracket.cursor" not in style for style in styles)