flxzt/rnote · error · anyhow::Error

stroke component does not contain 'value'.

Error message

stroke component does not contain 'value'.

What it means

This error is thrown during migration of an Rnote file (maj0min13 -> maj0min15) in TryFrom::try_from while iterating stroke_components of the engine snapshot. Each stroke component must be a JSON object with a 'value' key; when serde_json/ijson deserialization yields a component lacking 'value', the migration aborts. It indicates a malformed or hand-edited .rnote file whose stroke component entries deviate from the expected v0.13 schema.

Solutions

  1. Open the .rnote file in the Rnote version that wrote it and re-save/export it, then retry migration.
  2. Inspect the JSON inside the .rnote archive (zip) and check every entry in engine_snapshot.stroke_components for a 'value' key.
  3. Restore the file from a backup or autosave, since the file is likely corrupted or externally modified.
  4. If repairing manually, add the missing 'value' object (or null — null components are skipped) to the offending component.

Example fix

// repairing a hand-edited stroke component in the .rnote JSON
// before
{"type": "stroke", "brush": "..."}
// after
{"type": "stroke", "value": {"stroke": "..."}, "brush": "..."}
Defensive patterns

Strategy: validation

Validate before calling

fn stroke_components_valid(snapshot: &serde_json::Value) -> bool {
    snapshot.get("stroke_components")
        .and_then(|v| v.as_array())
        .map(|arr| arr.iter().all(|c|
            c.get("value").map_or(false, |v| v.is_object() || v.is_null())))
        .unwrap_or(false)
}

Type guard

fn has_value_field(comp: &serde_json::Value) -> bool {
    comp.get("value").is_some()
}

Try / catch

match RnoteFileMaj0Min15::try_from(file_maj0min13) {
    Ok(f) => open(f),
    Err(e) if e.to_string().contains("does not contain 'value'") => {
        log::error!("corrupt stroke component: {e}");
        offer_backup_restore();
    }
    Err(e) => return Err(e),
}

Prevention

When it happens

Trigger: Calling TryFrom::<RnoteFileMaj0Min13>::try_from (or the file-open migration path) on a snapshot where some element of engine_snapshot['stroke_components'] is a JSON object without a 'value' key.

Common situations: Opening an .rnote file produced or modified by an incompatible tool version, a partially written/corrupted file, or a hand-edited file where a stroke component's 'value' field was removed or renamed.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

AI-assisted analysis of flxzt/rnote@bbc5354502 (2026-09-08). Data as JSON: /api/errors/d5077dbe2494d254. Report an issue: GitHub.

Appendix: source

Thrown at crates/rnote-engine/src/fileformats/rnoteformat/maj0min15.rs:36

        let engine_snapshot = value
            .engine_snapshot
            .as_object_mut()
            .ok_or(anyhow!("engine snapshot is not a JSON object."))?;

        for comp in engine_snapshot
            .get_mut("stroke_components")
            .ok_or(anyhow!(
                "engine snapshot does not contain 'stroke_components'."
            ))?
            .as_array_mut()
            .ok_or(anyhow!("stroke components is not a JSON array."))?
            .iter_mut()
        {
            let value = comp
                .as_object_mut()
                .ok_or(anyhow!("stroke component is not a JSON object."))?
                .get_mut("value")
                .ok_or(anyhow!("stroke component does not contain 'value'."))?;
            if value.is_null() {
                continue;
            }
            if let Some(shapestroke) = value
                .as_object_mut()
                .ok_or(anyhow!("value is not a JSON object."))?
                .get_mut("shapestroke")
            {
                let shape = shapestroke
                    .as_object_mut()
                    .ok_or(anyhow!("shapestroke is not a JSON object."))?
                    .get_mut("shape")
                    .ok_or(anyhow!("shapestroke does not contain 'shape'."))?;

                if let Some(rect) = shape
                    .as_object_mut()
                    .ok_or(anyhow!("shape is not a JSON object."))?
                    .get_mut("rect")

View on GitHub (pinned to bbc5354502)