flxzt/rnote · error

Creating PenStyle from &str failed, invalid name

Error message

Creating PenStyle from &str failed, invalid name {s}

What it means

Parsing a string into PenStyle failed because the name did not match any known style (brush, shaper, typewriter, eraser, selector, tools). Raised by FromStr, typically during settings/config deserialization of the pen name.

Solutions

1. Use one of the exact valid names: brush, shaper, typewriter, eraser, selector, tools (all lowercase).
2. Correct the settings file or reset it to defaults.
3. Make the parser case-insensitive and/or add aliases for legacy names.
4. Fall back to a default style on parse failure with a warning instead of propagating the error.

Example fix

// before
s.to_string().parse::<PenStyle>()?; // "Brush" -> fails
// after
match s.to_lowercase().as_str() {
    "brush" | "pen" => PenStyle::Brush,
    other => return Err(anyhow!("Creating PenStyle from &str failed, invalid name {other}")),
}

// rust
const VALID_STYLES: [&str; 6] = ["brush", "shaper", "typewriter", "eraser", "selector", "tools"];
fn is_valid_style_name(s: &str) -> bool { VALID_STYLES.contains(&s) }

fn parse_style_loose(s: &str) -> Option<PenStyle> {
    s.to_lowercase().parse::<PenStyle>().ok()
}

let style = s.parse::<PenStyle>()
    .inspect_err(|e| log::warn!("{e}; using default"))
    .unwrap_or(PenStyle::Brush);

When it happens

Trigger: FromStr for PenStyle with strings like 'pen', 'highlighter', 'Brush' (case mismatch), or empty string from a malformed config.

Common situations: Hand-edited config files using old or renamed tool names; other applications writing different pen identifiers; locale/case differences.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Layout from_string failed, invalid name
• PenStyle try_from:: () for value failed
• SplitOrder try_from:: () for value failed
• PatternStyle try_from
• PredefinedFormat try_from

AI-assisted analysis of flxzt/rnote@bbc5354502 (2026-09-08). Data as JSON: /api/errors/297ff97e0ff4247d. Report an issue: GitHub.

Appendix: source

Thrown at crates/rnote-engine/src/pens/mod.rs:242

    fn try_from(value: u32) -> Result<Self, Self::Error> {
        num_traits::FromPrimitive::from_u32(value)
            .ok_or_else(|| anyhow::anyhow!("PenStyle try_from::<u32>() for value {} failed", value))
    }
}

impl std::str::FromStr for PenStyle {
    type Err = anyhow::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "brush" => Ok(Self::Brush),
            "shaper" => Ok(Self::Shaper),
            "typewriter" => Ok(Self::Typewriter),
            "eraser" => Ok(Self::Eraser),
            "selector" => Ok(Self::Selector),
            "tools" => Ok(Self::Tools),
            s => Err(anyhow::anyhow!(
                "Creating PenStyle from &str failed, invalid name {s}"
            )),
        }
    }
}

impl Display for PenStyle {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            PenStyle::Brush => write!(f, "brush"),
            PenStyle::Shaper => write!(f, "shaper"),
            PenStyle::Typewriter => write!(f, "typewriter"),
            PenStyle::Eraser => write!(f, "eraser"),
            PenStyle::Selector => write!(f, "selector"),
            PenStyle::Tools => write!(f, "tools"),
        }
    }
}

View on GitHub (pinned to bbc5354502)