invalid RGBA hex color: '{value}'. Expected #rgb, #rgba, #rr

Error message

invalid RGBA hex color: '{value}'. Expected #rgb, #rgba, #rrggbb, or #rrggbbaa

What it means

TryFrom<&str> for Rgba trims the input and splits once on '#'; the parse only succeeds when the result is exactly ("", hex), i.e. a pure '#'-prefixed literal. This first bail fires when there is no '#' at all, or when text precedes the '#'. CSS color functions and named colors are not supported by this parser.

Source

Thrown at crates/gpui/src/color.rs:237

            a: color.a,
        }
    }
}

impl TryFrom<&'_ str> for Rgba {
    type Error = anyhow::Error;

    fn try_from(value: &'_ str) -> Result<Self, Self::Error> {
        const RGB: usize = "rgb".len();
        const RGBA: usize = "rgba".len();
        const RRGGBB: usize = "rrggbb".len();
        const RRGGBBAA: usize = "rrggbbaa".len();

        const EXPECTED_FORMATS: &str = "Expected #rgb, #rgba, #rrggbb, or #rrggbbaa";
        const INVALID_UNICODE: &str = "invalid unicode characters in color";

        let Some(("", hex)) = value.trim().split_once('#') else {
            bail!("invalid RGBA hex color: '{value}'. {EXPECTED_FORMATS}");
        };

        let (r, g, b, a) = match hex.len() {
            RGB | RGBA => {
                let r = u8::from_str_radix(
                    hex.get(0..1).with_context(|| {
                        format!("{INVALID_UNICODE}: r component of #rgb/#rgba for value: '{value}'")
                    })?,
                    16,
                )?;
                let g = u8::from_str_radix(
                    hex.get(1..2).with_context(|| {
                        format!("{INVALID_UNICODE}: g component of #rgb/#rgba for value: '{value}'")
                    })?,
                    16,
                )?;
                let b = u8::from_str_radix(
                    hex.get(2..3).with_context(|| {

View on GitHub (pinned to f4178619ac)

Solutions

Use one of the accepted literals: #rgb, #rgba, #rrggbb, #rrggbbaa
If input is user-facing, strip non-hex prefixes and add the '#' before conversion
Validate color strings at settings load time so the error names the offending key

Example fix

// before
let color = Rgba::try_from("1e1e2e")?; // no '#' -> bail

// after
let color = Rgba::try_from("#1e1e2e")?;

Defensive patterns

Strategy: validation

Validate before calling

fn is_valid_hex_color(value: &str) -> bool {
    let Some(hex) = value.trim().strip_prefix('#') else { return false };
    matches!(hex.len(), 3 | 4 | 6 | 8) && hex.chars().all(|c| c.is_ascii_hexdigit())
}

Type guard

fn is_hex_color(value: &str) -> bool {
    value.trim().starts_with('#') && value.trim().chars().skip(1).all(|c| c.is_ascii_hexdigit())
}

Try / catch

let color = Rgba::try_from(raw).with_context(|| format!("invalid color '{raw}' for setting '{key}'"))?;

Prevention

Store colors as typed Rgba values, not strings, wherever possible
Validate all color fields when loading settings or themes and report the offending key
Document the four accepted formats next to user-facing color settings

When it happens

Trigger: Converting strings like ff0000 (missing '#'), rgb(255,0,0), red, or 'color: #ff0000' into Rgba via theme or settings parsing, or any API that accepts color strings.

Common situations: Hand-edited theme or settings files using CSS syntax instead of hex; copy-pasted colors without the '#'; strings with labels or prefixes from other config formats.

Related errors

AI-assisted analysis of zed-industries/zed@f4178619ac (2026-08-20). Data as JSON: /api/errors/83e6c6395e1ae1f0. Report an issue: GitHub.