Extra newlines in console.render_lines output

[cadojo]

I'm trying to write a custom RenderableType that prints a | before every line of content. This could be used to pretty-print messages to a user, etc.

>>> rich.print(Message("Hello, world!"))
│ Message
│ 
│ Hello, world!  

The problem is, multi-line messages have newlines in places I don't expect. Segment doesn't add newlines by default, I don't think.

# My output looks like this
>>> rich.print(Message("Hello\nWorld!"))
│ Message
│ 
│ Hello      
                                                                                                                                                                                      
│ World!                                                                                                                                                                                           

Here's the really weird thing... when I copy and paste the output of the terminal into GitHub here, the extra newlines actually disappear. I had to manually add the newline between "Hello" and "World" above to show you what the result looks like in my terminal.

# Copying and pasting the output looks like this
>>> rich.print(Message("Hello\nWorld!"))
│ Message
│ 
│ Hello                                                                           
│ World!                                                                          

The method I'm using is below... for reference, the whole class is at the bottom of this post. Does anyone see anything glaringly wrong with the __rich_console__ method below? I can't figure out why render_lines sometimes has two newlines at the end of line.

def __rich_console__(self, console: Console, options: ConsoleOptions) -> Iterable[Segment]:
    """Render the message as a rich string."""
    from rich.segment import Segment, Segments
    from rich.text    import Text
    from rich.padding import Padding

    header    = Text(self.header.rstrip(), style = console.get_style(self.header_style), end = "") if isinstance(self.header, str) else self.header
    separator = Segment("│ ", style = console.get_style(self.header_style))
    content   = Text(self.content, style = console.get_style(self.style), end = "") if isinstance(self.content, str) else self.content
    content   = Padding(content, (0, 3, 0, 0))

    yield separator
    yield header
    yield Segment.line()
    yield separator
    yield Segment.line()
    for line in console.render_lines(content, options = options, style = console.get_style(self.style), new_lines=True):
        yield separator
        yield from line

Full Class

"""Rich-formatted types!

More to come!
"""

from dataclasses  import dataclass
from os import sep
from typing       import Iterable
from rich.segment import Segment
from rich.style   import Style
from rich.text    import Text
from rich.console import Console, ConsoleOptions, Measurement, ConsoleRenderable


@dataclass(frozen=False, slots=True, repr=False, unsafe_hash=True)
class Message:
    """A rich-formatted message, with built-in themes!
    
    More to come!
    """
    
    content:      str | ConsoleRenderable
    style:        str | Style = "none"
    header:       str | Text  = "Message"
    header_style: str | Style = "bold"

    def __str__(self) -> str:
        """Render the message as a str."""
        return str(self.content)
    
    def __repr__(self) -> str:
        return f"Message(content={self.content}, style={self.style}, header={self.header}, header_style={self.header_style})"

    def __rich_console__(self, console: Console, options: ConsoleOptions) -> Iterable[Segment]:
        """Render the message as a rich string."""
        from rich.segment import Segment, Segments
        from rich.text    import Text
        from rich.padding import Padding

        header    = Text(self.header.rstrip(), style = console.get_style(self.header_style), end = "") if isinstance(self.header, str) else self.header
        separator = Segment("│ ", style = console.get_style(self.header_style))
        content   = Text(self.content, style = console.get_style(self.style), end = "") if isinstance(self.content, str) else self.content
        content   = Padding(content, (0, 3, 0, 0))

        yield separator
        yield header
        yield Segment.line()
        yield separator
        yield Segment.line()
        for line in console.render_lines(content, options = options, style = console.get_style(self.style), new_lines=True):
            yield separator
            yield from line


    def __rich_measure__(self, console: Console, options: ConsoleOptions) -> Measurement:
        """Measure the message."""
        from math import floor
        return Measurement(
            floor(len(self.header) * 1.25) if self.header else 8, 
            options.max_width
        )

    @classmethod
    def note(cls, content: ConsoleRenderable, style: str | Style = "none", header: str = "Note", header_style: str | Style  = "bold violet") -> "Message":
        """A note message."""
        return cls(content, style, header, header_style)

    @classmethod
    def tip(cls, content: ConsoleRenderable, style: str | Style = "none", header: str = "Tip", header_style: str | Style  = "bold green") -> "Message":
        """A tip message."""
        return cls(content, style, header, header_style)

    @classmethod
    def info(cls, content: ConsoleRenderable, style: str | Style = "none", header: str = "Info", header_style: str | Style  = "bold cyan") -> "Message":
        """An info message."""
        return cls(content, style, header, header_style)

    @classmethod
    def warning(cls, content: ConsoleRenderable, style: str | Style = "none", header: str = "Info", header_style: str | Style  = "bold orange3") -> "Message":
        """A warning message."""
        return cls(content, style, header, header_style)

    @classmethod
    def danger(cls, content: ConsoleRenderable, style: str | Style = "none", header: str = "Info", header_style: str | Style  = "bold red") -> "Message":
        """A danger message."""
        return cls(content, style, header, header_style)

del (
    Iterable,
    Segment, 
    Style, 
    Text, 
    Console, 
    ConsoleOptions, 
    Measurement, 
    ConsoleRenderable,
)

[willmcgugan]

The problem there is not new lines, but spaces. You are writing spaces past the ned of the line which wrap and push the following line down. That's why you don't see any new lines when you cut and paste them.

render_lines is padding to the full width and your separator segment is adding a few characters. You can tell render_lines to adjust to a smaller space by doing options=options.update_width(options.width - 2). Alternatively you can set pad=False on render_lines so that it doesn't add spaces.

[cadojo]

Ah thank you for the quick reply!