ssssssss-team/spider-flow · error · IndexOutOfBoundsException

End outside of string.

Error message

End outside of string.

What it means

The Span(String,int,int) constructor throws IndexOutOfBoundsException("End outside of string.") when end exceeds source.length(). A span cannot extend beyond the last character of the source it references. This guards the subsequent source.substring(start, end) call from failing.

Solutions

1. Clamp end to source.length(): end = Math.min(end, source.length()).
2. Fix the offset arithmetic that produced an out-of-range end.
3. Verify the source string is the same (complete) text the offsets were computed against.
4. Use the single-argument Span(source) constructor for full-source spans.

Example fix

// before
Span span = new Span(source, start, start + tokenLen);
// after
Span span = new Span(source, start, Math.min(start + tokenLen, source.length()));

if (end > source.length()) throw new IllegalArgumentException("end " + end + " exceeds source length " + source.length());
Span span = new Span(source, start, Math.min(end, source.length()));

boolean isValidSpanRange(String source, int start, int end) {
    return source != null && start >= 0 && start <= end && end <= source.length() && start < source.length();
}

try {
    Span span = new Span(source, start, end);
} catch (IndexOutOfBoundsException e) {
    Span span = new Span(source, start, source.length());
}

When it happens

Trigger: Calling new Span(source, start, end) with end > source.length(), typically after computing an end offset with an inclusive/exclusive mix-up or over-advancing a cursor.

Common situations: Using end = start + tokenLength where the token runs past the input; passing matched-region offsets from a regex that already account for a terminator incorrectly.

Related errors

• Start must be >= 0.
• Start outside of string.
• Start must be >= 0.
• Start must be <= end.
• The two spans do not reference the same source.

AI-assisted analysis of ssssssss-team/spider-flow@c799cca99c (2026-09-08). Data as JSON: /api/errors/e26496f122f7e544. Report an issue: GitHub.

Appendix: source

Thrown at spider-flow-core/src/main/java/org/spiderflow/core/expression/parsing/Span.java:27

	/** start index in source string, starting at 0 **/
	private int start;

	/** end index in source string, exclusive, starting at 0 **/
	private int end;

	/** Cached String instance to reduce pressure on GC **/
	private final String cachedText;

	public Span (String source) {
		this(source, 0, source.length());
	}

	public Span (String source, int start, int end) {
		if (start > end) throw new IllegalArgumentException("Start must be <= end.");
		if (start < 0) throw new IndexOutOfBoundsException("Start must be >= 0.");
		if (start > source.length() - 1) 
			throw new IndexOutOfBoundsException("Start outside of string.");
		if (end >source.length()) throw new IndexOutOfBoundsException("End outside of string.");

		this.source = source;
		this.start = start;
		this.end = end;
		this.cachedText = source.substring(start, end);
	}

	public Span (Span start, Span end) {
		if (!start.source.equals(end.source)) throw new IllegalArgumentException("The two spans do not reference the same source.");
		if (start.start > end.end) throw new IllegalArgumentException("Start must be <= end.");
		if (start.start < 0) throw new IndexOutOfBoundsException("Start must be >= 0.");
		if (start.start > start.source.length() - 1) throw new IndexOutOfBoundsException("Start outside of string.");
		if (end.end > start.source.length()) throw new IndexOutOfBoundsException("End outside of string.");

		this.source = start.source;
		this.start = start.start;
		this.end = end.end;
		this.cachedText = source.substring(this.start, this.end);

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