apache/cassandra · error · InvalidTypeException

Cannot parse collection value from "%s", at character %d exp

Error message

Cannot parse collection value from "%s", at character %d expecting '%s' but got '%c'

What it means

Thrown by collection codecs' parse() when converting a CQL literal string (e.g. from cqlsh output or a query string) fails because the first non-space character is not the expected opening character ('[' for lists, '{' for sets/maps). The parser reports the position and what it found instead. parse() only accepts well-formed CQL collection literals or null.

Source

Thrown at src/java/org/apache/cassandra/cql3/functions/types/TypeCodec.java:2188

            sb.append(getOpeningChar());
            int i = 0;
            for (E v : value)
            {
                if (i++ != 0) sb.append(',');
                sb.append(eltCodec.format(v));
            }
            sb.append(getClosingChar());
            return sb.toString();
        }

        @Override
        public C parse(String value)
        {
            if (value == null || value.isEmpty() || value.equalsIgnoreCase("NULL")) return null;

            int idx = ParseUtils.skipSpaces(value, 0);
            if (value.charAt(idx++) != getOpeningChar())
                throw new InvalidTypeException(
                String.format(
                "Cannot parse collection value from \"%s\", at character %d expecting '%s' but got '%c'",
                value, idx, getOpeningChar(), value.charAt(idx)));

            idx = ParseUtils.skipSpaces(value, idx);

            if (value.charAt(idx) == getClosingChar()) return newInstance(0);

            C l = newInstance(10);
            while (idx < value.length())
            {
                int n;
                try
                {
                    n = ParseUtils.skipCQLValue(value, idx);
                }
                catch (IllegalArgumentException e)
                {

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Pass a properly delimited CQL collection literal: list/set as [v1,v2] or {v1,v2}, map as {k1:v1,k2:v2}
2. Trim and validate the string starts with the codec's opening character before calling parse()
3. Bind typed Java collections instead of parsing strings (recommended): use setList/setSet/setMap or the codec's serialize path
4. If the input is JSON, convert it to a CQL literal first (e.g. build a List and let the codec format it with format()).

Example fix

// before
List<Integer> l = intListCodec.parse("1,2,3"); // InvalidTypeException
// after
List<Integer> l = intListCodec.parse("[1,2,3]");

// before parse
String v = input == null ? null : input.trim();
if (v == null || v.equalsIgnoreCase("null")) return null;
if (!(v.startsWith("[") || v.startsWith("{")))
    throw new IllegalArgumentException("Expected CQL collection literal starting with '[' or '{': " + input);

static boolean isCollectionLiteral(String s) {
    if (s == null) return false;
    String t = s.trim();
    return (t.startsWith("[") && t.endsWith("]")) || (t.startsWith("{") && t.endsWith("}"));
}

try {
    return codec.parse(literal);
} catch (InvalidTypeException e) {
    LOG.warn("Bad collection literal: {}", e.getMessage());
    return null;
}

When it happens

Trigger: Calling codec.parse() (or session.prepare/execute paths that parse literals) with a string missing the opening bracket/brace — e.g. "1,2,3" instead of "[1,2,3]", or a quoted/mismatched delimiter like "(1,2,3)".

Common situations: Copying values out of cqlsh without delimiters; passing JSON arrays ("[1,2]" works but "{\"a\":1}" does not for a map); confusing set/map opening char '{' with list '[' after changing column type; empty-ish strings with stray whitespace then a wrong char.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• Cannot parse collection value from "%s", invalid CQL value a
• Cannot parse collection value from "%s", at character %d exp
• Cannot parse 32-bits int value from "%s"
• Cannot parse timestamp value from "%s"
• Cannot parse date value from "%s"

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/90c105136541065a. Report an issue: GitHub.