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Fixed bug where rich_utils._apply_style_wrapper() could strip a trailing newline. #1514

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Merged
merged 1 commit into from
Sep 16, 2025
Merged

Fixed bug where rich_utils._apply_style_wrapper() could strip a trailing newline. #1514

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4 changes: 2 additions & 2 deletions cmd2/rich_utils.py
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Original file line number Diff line number Diff line change
Expand Up @@ -416,9 +416,9 @@ def _apply_style_wrapper(cls: type[Segment], *args: Any, **kwargs: Any) -> Itera
styled_segments = list(_orig_segment_apply_style(*args, **kwargs))
newline_segment = cls.line()

# If the final segment is a newline, it will be stripped by Segment.split_lines().
# If the final segment ends in a newline, that newline will be stripped by Segment.split_lines().
# Save an unstyled newline to restore later.
end_segment = newline_segment if styled_segments and styled_segments[-1].text == "\n" else None
end_segment = newline_segment if styled_segments and styled_segments[-1].text.endswith("\n") else None

# Use Segment.split_lines() to separate the styled text from the newlines.
# This way the ANSI reset code will appear before any newline.
Expand Down
94 changes: 74 additions & 20 deletions tests/test_rich_utils.py
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Original file line number Diff line number Diff line change
Expand Up @@ -147,101 +147,106 @@ def test_from_ansi_wrapper() -> None:

@pytest.mark.parametrize(
# Print with style and verify that everything but newline characters have style.
('objects', 'expected', 'sep', 'end'),
('objects', 'sep', 'end', 'expected'),
[
# Print nothing
((), "\n", " ", "\n"),
((), " ", "\n", "\n"),
# Empty string
(("",), "\n", " ", "\n"),
(("",), " ", "\n", "\n"),
# Multple empty strings
(("", ""), '\x1b[34;47m \x1b[0m\n', " ", "\n"),
(("", ""), " ", "\n", "\x1b[34;47m \x1b[0m\n"),
# Basic string
(
("str_1",),
"\x1b[34;47mstr_1\x1b[0m\n",
" ",
"\n",
"\x1b[34;47mstr_1\x1b[0m\n",
),
# String which ends with newline
(
("str_1\n",),
"\x1b[34;47mstr_1\x1b[0m\n\n",
" ",
"\n",
"\x1b[34;47mstr_1\x1b[0m\n\n",
),
# String which ends with multiple newlines
(
("str_1\n\n",),
"\x1b[34;47mstr_1\x1b[0m\n\n\n",
" ",
"\n",
"\x1b[34;47mstr_1\x1b[0m\n\n\n",
),
# Mutiple lines
(
("str_1\nstr_2",),
"\x1b[34;47mstr_1\x1b[0m\n\x1b[34;47mstr_2\x1b[0m\n",
" ",
"\n",
"\x1b[34;47mstr_1\x1b[0m\n\x1b[34;47mstr_2\x1b[0m\n",
),
# Multiple strings
(
("str_1", "str_2"),
"\x1b[34;47mstr_1 str_2\x1b[0m\n",
" ",
"\n",
"\x1b[34;47mstr_1 str_2\x1b[0m\n",
),
# Multiple strings with newline between them.
(
("str_1\n", "str_2"),
"\x1b[34;47mstr_1\x1b[0m\n\x1b[34;47m str_2\x1b[0m\n",
" ",
"\n",
"\x1b[34;47mstr_1\x1b[0m\n\x1b[34;47m str_2\x1b[0m\n",
),
# Multiple strings and non-space value for sep
(
("str_1", "str_2"),
"\x1b[34;47mstr_1(sep)str_2\x1b[0m\n",
"(sep)",
"\n",
"\x1b[34;47mstr_1(sep)str_2\x1b[0m\n",
),
# Multiple strings and sep is a newline
(
("str_1", "str_2"),
"\x1b[34;47mstr_1\x1b[0m\n\x1b[34;47mstr_2\x1b[0m\n",
"\n",
"\n",
"\x1b[34;47mstr_1\x1b[0m\n\x1b[34;47mstr_2\x1b[0m\n",
),
# Multiple strings and sep has newlines
(
("str_1", "str_2"),
"\x1b[34;47mstr_1(sep1)\x1b[0m\n\x1b[34;47m(sep2)str_2\x1b[0m\n",
"(sep1)\n(sep2)",
"(sep1)\n(sep2)\n",
"\n",
("\x1b[34;47mstr_1(sep1)\x1b[0m\n\x1b[34;47m(sep2)\x1b[0m\n\x1b[34;47mstr_2\x1b[0m\n"),
),
# Non-newline value for end.
(
("str_1", "str_2"),
"\x1b[34;47mstr_1(sep1)\x1b[0m\n\x1b[34;47m(sep2)str_2\x1b[0m\x1b[34;47m(end)\x1b[0m",
"(sep1)\n(sep2)",
"(end)",
"\x1b[34;47mstr_1(sep1)\x1b[0m\n\x1b[34;47m(sep2)str_2\x1b[0m\x1b[34;47m(end)\x1b[0m",
),
# end has newlines.
(
("str_1", "str_2"),
"\x1b[34;47mstr_1(sep1)\x1b[0m\n\x1b[34;47m(sep2)str_2\x1b[0m\x1b[34;47m(end1)\x1b[0m\n\x1b[34;47m(end2)\x1b[0m",
"(sep1)\n(sep2)",
"(end1)\n(end2)",
"(sep1)\n(sep2)\n",
"(end1)\n(end2)\n",
(
"\x1b[34;47mstr_1(sep1)\x1b[0m\n"
"\x1b[34;47m(sep2)\x1b[0m\n"
"\x1b[34;47mstr_2\x1b[0m\x1b[34;47m(end1)\x1b[0m\n"
"\x1b[34;47m(end2)\x1b[0m\n"
),
),
# Empty sep and end values
(
("str_1", "str_2"),
"\x1b[34;47mstr_1str_2\x1b[0m",
"",
"",
"\x1b[34;47mstr_1str_2\x1b[0m",
),
],
)
def test_apply_style_wrapper(objects: tuple[str], expected: str, sep: str, end: str) -> None:
def test_apply_style_wrapper_soft_wrap(objects: tuple[str], sep: str, end: str, expected: str) -> None:
# Check if we are still patching Segment.apply_style(). If this check fails, then Rich
# has fixed the bug. Therefore, we can remove this test function and ru._apply_style_wrapper.
assert Segment.apply_style.__func__ is ru._apply_style_wrapper.__func__ # type: ignore[attr-defined]
Expand Down Expand Up @@ -275,3 +280,52 @@ def test_apply_style_wrapper(objects: tuple[str], expected: str, sep: str, end:
finally:
# Restore the patch
Segment.apply_style = ru._apply_style_wrapper # type: ignore[assignment]


def test_apply_style_wrapper_word_wrap() -> None:
"""
Test that our patch didn't mess up word wrapping.
Make sure it does not insert styled newlines or apply style to existing newlines.
"""
# Check if we are still patching Segment.apply_style(). If this check fails, then Rich
# has fixed the bug. Therefore, we can remove this test function and ru._apply_style_wrapper.
assert Segment.apply_style.__func__ is ru._apply_style_wrapper.__func__ # type: ignore[attr-defined]

str1 = "this\nwill word wrap\n"
str2 = "and\nso will this\n"
sep = "(sep1)\n(sep2)\n"
end = "(end1)\n(end2)\n"
style = "blue on white"

# All newlines should appear outside of ANSI style sequences.
expected = (
"\x1b[34;47mthis\x1b[0m\n"
"\x1b[34;47mwill word \x1b[0m\n"
"\x1b[34;47mwrap\x1b[0m\n"
"\x1b[34;47m(sep1)\x1b[0m\n"
"\x1b[34;47m(sep2)\x1b[0m\n"
"\x1b[34;47mand\x1b[0m\n"
"\x1b[34;47mso will \x1b[0m\n"
"\x1b[34;47mthis\x1b[0m\n"
"\x1b[34;47m(end1)\x1b[0m\n"
"\x1b[34;47m(end2)\x1b[0m\n"
)

# Set a width which will cause word wrapping.
console = Console(force_terminal=True, width=10)

try:
with console.capture() as capture:
console.print(str1, str2, sep=sep, end=end, style=style, soft_wrap=False)
assert capture.get() == expected

# Now remove our patch and make sure it produced the same result as unpatched Rich.
Segment.apply_style = ru._orig_segment_apply_style # type: ignore[assignment]

with console.capture() as capture:
console.print(str1, str2, sep=sep, end=end, style=style, soft_wrap=False)
assert capture.get() == expected

finally:
# Restore the patch
Segment.apply_style = ru._apply_style_wrapper # type: ignore[assignment]
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