microsoft/edit · error

Unrecognized InCB= for U+ to U+

Error message

Unrecognized InCB={} for U+{:04X} to U+{:04X}

What it means

After validating the GCB/InCB combination, the generator maps the Indic_Conjunct_Break string to InCBLinker/InCBConsonant; any other non-None/non-Extend string reaches the catch-all bail. Like the GCB check, this protects the exhaustiveness of generated tables against unknown Unicode data values.

Solutions

1. Use the official UCD XML matching the generator's supported Unicode version.
2. Add the new InCB value to ClusterBreak and a mapping arm in extract_values_from_ucd.
3. Verify the field is populated from the Indic_Conjunct_Break attribute (check the parsing code) if values look shifted.

Example fix

// before
_ => bail!("Unrecognized InCB={} ..."),
// after
"NewKind" => ClusterBreak::InCBNewKind,
_ => bail!("Unrecognized InCB={} ..."),

// validate InCB attribute domain before generating
const INCB_VALUES: &[&str] = &["None", "Extend", "Linker", "Consonant"];
for node in doc.descendants().filter(|n| n.has_attribute("InCB")) {
    let v = node.attribute("InCB").unwrap();
    assert!(INCB_VALUES.contains(&v), "unknown InCB value {v}");
}

match generate(&ucd_path) {
    Err(e) if e.to_string().starts_with("Unrecognized InCB=") => {
        eprintln!("UCD contains an InCB value this generator does not model: {e}");
        std::process::exit(1);
    }
    r => r?,
}

When it happens

Trigger: A UCD XML containing an Indic_Conjunct_Break value outside {None, Extend, Linker, Consonant} — a newer Unicode property value, a misspelled/hand-edited attribute, or a different UCD property accidentally parsed into indic_conjunct_break.

Common situations: Future Unicode versions adding InCB values; corrupted or third-party-modified UCD files; wiring the wrong XML attribute into char_attributes.indic_conjunct_break during a refactor.

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

• Unrecognized GCB= for U+ to U+
• Unexpected GCB= with ExtPict=Y for U+ to U+
• Unexpected GCB= with InCB= for U+ to U+
• Unrecognized ea= for U+ to U+

AI-assisted analysis of microsoft/edit@826b4c097b (2026-09-06). Data as JSON: /api/errors/24a0444bb1d44772. Report an issue: GitHub.

Appendix: source

Thrown at crates/unicode-gen/src/main.rs:847

            }

            if !matches!(char_attributes.indic_conjunct_break, "None" | "Extend") {
                // If it's not None/Extend, it's Linker/Consonant, and currently
                // all of them are GCB=EX/XX. Since we treat them almost like extenders,
                // we need to revisit our assumptions if this ever changes.
                if !matches!(cb, ClusterBreak::Other | ClusterBreak::Extend) {
                    bail!(
                        "Unexpected GCB={} with InCB={} for U+{:04X} to U+{:04X}",
                        char_attributes.grapheme_cluster_break,
                        char_attributes.indic_conjunct_break,
                        range.start(),
                        range.end()
                    );
                }
                cb = match char_attributes.indic_conjunct_break {
                    "Linker" => ClusterBreak::InCBLinker,
                    "Consonant" => ClusterBreak::InCBConsonant,
                    _ => bail!(
                        "Unrecognized InCB={} for U+{:04X} to U+{:04X}",
                        char_attributes.indic_conjunct_break,
                        range.start(),
                        range.end()
                    ),
                };
            }

            let mut cw = match char_attributes.east_asian {
                "N" | "Na" | "H" => CharacterWidth::Narrow, // Half-width, Narrow, Neutral
                "F" | "W" => CharacterWidth::Wide,          // Wide, Full-width
                "A" => ambiguous_value,                     // Ambiguous
                _ => bail!(
                    "Unrecognized ea={} for U+{:04X} to U+{:04X}",
                    char_attributes.east_asian,
                    range.start(),
                    range.end()
                ),

View on GitHub (pinned to 826b4c097b)