JamesNK/Newtonsoft.Json · error · JsonException

Unexpected end while parsing path.

Error message

Unexpected end while parsing path.

What it means

Thrown by the JPath parser when the path ends (or a query boundary is reached) immediately after a dot, with no field name following it. ParsePath detects the followingDot flag combined with the end of the base path and rejects the dangling separator.

Source

Thrown at Src/Newtonsoft.Json/Linq/JsonPath/JPath.cs:194

            }

            bool atPathEnd = (_currentIndex == _expression.Length);

            if (_currentIndex > currentPartStartIndex)
            {
                string? member = _expression.Substring(currentPartStartIndex, _currentIndex - currentPartStartIndex).TrimEnd();
                if (member == "*")
                {
                    member = null;
                }
                filters.Add(CreatePathFilter(member, scan));
            }
            else
            {
                // no field name following dot in path and at end of base path/query
                if (followingDot && (atPathEnd || query))
                {
                    throw new JsonException("Unexpected end while parsing path.");
                }
            }

            return atPathEnd;
        }

        private static PathFilter CreatePathFilter(string? member, bool scan)
        {
            PathFilter filter = (scan) ? (PathFilter)new ScanFilter(member) : new FieldFilter(member);
            return filter;
        }

        private PathFilter ParseIndexer(char indexerOpenChar, bool scan)
        {
            _currentIndex++;

            char indexerCloseChar = (indexerOpenChar == '[') ? ']' : ')';

View on GitHub (pinned to 4f73e74372)

Solutions

1. Remove the trailing dot from the path.
2. When building paths dynamically, append '.' only between segments, never after the last one.
3. Trim trailing dots from the final expression string before passing it to SelectToken.

Example fix

// before
var path = "$.data.";
token.SelectToken(path);

// after
var path = "$.data";
token.SelectToken(path);

// Trim trailing dots/separators before querying
path = path.TrimEnd('.');
token.SelectToken(path);

try
{
    token.SelectToken(path);
}
catch (JsonException ex) when (ex.Message.Contains("Unexpected end while parsing path"))
{
    path = path.TrimEnd('.');
    token.SelectToken(path);
}

When it happens

Trigger: A path like token.SelectToken("$.data.") or "$.." where a dot is the last meaningful token. ParsePath.cs:192-194 fires because followingDot is true and atPathEnd is true with no member text.

Common situations: Trailing dots left by string trimming or concatenation bugs; building a path in a loop that appends '.' unconditionally; a recursive '..' with nothing after it.

Related errors

• Unexpected character while parsing path:
• Unexpected character following indexer:
• Path ended with open indexer.
• Array index expected.
• Unexpected character while parsing path indexer:

AI-assisted analysis of JamesNK/Newtonsoft.Json@4f73e74372 (2026-08-07). Data as JSON: /api/errors/032630b8f2b6846f. Report an issue: GitHub.