tui-cs/Terminal.Gui · error · JsonException

After {propertyName}: Invalid Json.

Error message

After {propertyName}: Invalid Json.

What it means

The read loop exited (reader.Read returned false) without ever hitting an EndObject token — the JSON object for the Scheme was truncated or never closed. The converter falls through the while loop and throws.

Source

Thrown at Terminal.Gui/Configuration/SchemeJsonConverter.cs:79

                    "codenumber" => scheme with { CodeNumber = attribute },
                    "codeoperator" => scheme with { CodeOperator = attribute },
                    "codetype" => scheme with { CodeType = attribute },
                    "codepreprocessor" => scheme with { CodePreprocessor = attribute },
                    "codeidentifier" => scheme with { CodeIdentifier = attribute },
                    "codeconstant" => scheme with { CodeConstant = attribute },
                    "codepunctuation" => scheme with { CodePunctuation = attribute },
                    "codefunctionname" => scheme with { CodeFunctionName = attribute },
                    "codeattribute" => scheme with { CodeAttribute = attribute },
                    _ => throw new JsonException ($"{propertyName}: Unrecognized Scheme Attribute name.")
                };
            }
            else
            {
                throw new JsonException ("null property name.");
            }
        }

        throw new JsonException ($"After {propertyName}: Invalid Json.");
    }

    /// <inheritdoc/>
    public override void Write (Utf8JsonWriter writer, Scheme value, JsonSerializerOptions options)
    {
        writer.WriteStartObject ();

        foreach (VisualRole role in Enum.GetValues<VisualRole> ())
        {
            // Get the attribute for the role

            if (!value.TryGetExplicitlySetAttributeForRole (role, out Attribute? attribute))
            {
                // Skip attributes that are not explicitly set
                continue;
            }
            writer.WritePropertyName (role.ToString ());
            // Write the attribute using the AttributeJsonConverter

View on GitHub (pinned to 2e47b11478)

Solutions

1. Add the missing closing brace(s) for the Scheme object.
2. Validate the JSON is complete and balanced.

Example fix

// before
{ "Normal": { "Foreground": "White" }
// after
{ "Normal": { "Foreground": "White" } }

// Confirm the whole document is complete and balanced
try { using var doc = JsonDocument.Parse (File.ReadAllText (path)); }
catch (JsonException ex) { /* truncated; ex has byte position */ }

try { ConfigurationManager.Apply (); }
catch (JsonException ex) when (ex.Message.Contains ("Invalid Json"))
{ /* likely a missing closing brace; ex.Message names last propertyName */ }

When it happens

Trigger: A Scheme object missing its closing brace, e.g. { "Normal": {...} (no matching }), or a truncated file cut off mid-object.

Common situations: Truncated config file (disk full, copy-paste cut off); missing closing brace from hand-editing.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• After {propertyName}: Expected PropertyName but got another
• Unexpected StartObject token when parsing Scheme: {reader.To
• After {propertyName}: Expected Attribute but got {attrObj?.G
• {propertyName}: Unrecognized Scheme Attribute name.
• null property name.

AI-assisted analysis of tui-cs/Terminal.Gui@2e47b11478 (2026-08-13). Data as JSON: /api/errors/23635e07bfce5820. Report an issue: GitHub.