NationalSecurityAgency/ghidra · error · IllegalArgumentException

Data not in a structure

Error message

Data not in a structure

What it means

Thrown by CreateStructureInStructureCmd.initializeStructureData when the parent datatype of the selected component is not a Structure. The command navigates comp1.getParent().getBaseDataType() and requires it to be a Structure to perform component replacement; a Union, Array, Typedef-to-non-structure, or other composite triggers the error.

Source

Thrown at Ghidra/Features/Base/src/main/java/ghidra/app/cmd/data/CreateStructureInStructureCmd.java:93

		}

		return structure;
	}

	/*
	 * @see AbstractCreateStructureCmd#initializeStructureData(StructureInfo)
	 */
	/*package*/ @Override
	DataType initializeStructureData(Program program, Structure localStructure) {

		Data data = program.getListing().getDataContaining(getStructureAddress());
		Data comp1 = data.getComponent(fromPath);
		Data comp2 = data.getComponent(toPath);
		int dataLength = (comp2.getParentOffset() + comp2.getLength()) - comp1.getParentOffset();

		DataType parentDataType = comp1.getParent().getBaseDataType();
		if (!(parentDataType instanceof Structure)) {
			throw new IllegalArgumentException("Data not in a structure");
		}
		Structure originalStructure = (Structure) parentDataType;

		// clear and initialize the original structure and then get the new
		// data
		clearStruct(originalStructure, comp1.getParentOffset(), dataLength);
		originalStructure.replace(comp1.getComponentIndex(), localStructure,
			localStructure.getLength());
		comp1 = data.getComponent(fromPath);

		return comp1.getDataType();
	}

	private void clearStruct(Structure struct, int offset, int length) {
		DataTypeComponent[] comps = struct.getDefinedComponents();
		int endOffset = offset + length;
		for (int i = comps.length - 1; i >= 0; i--) {
			if (comps[i].getOffset() >= offset && comps[i].getOffset() < endOffset) {

View on GitHub (pinned to d5f144c24d)

Solutions

1. Run the command only when the parent composite is a Structure.
2. Check `comp1.getParent().getBaseDataType() instanceof Structure` before invoking the command.
3. For Unions, restructure the data differently - you cannot 'create structure in structure' inside a Union.

Example fix

// before
new CreateStructureInStructureCmd(addr, fromPath, toPath).applyTo(program);
// parent is a Union -> IllegalArgumentException

// after
Data comp1 = program.getListing().getDataContaining(addr).getComponent(fromPath);
if (!(comp1.getParent().getBaseDataType() instanceof Structure)) {
    Msg.warn(this, "Cannot create structure-in-structure: parent is " +
        comp1.getParent().getBaseDataType().getClass().getSimpleName());
    return;
}
new CreateStructureInStructureCmd(addr, fromPath, toPath).applyTo(program);

Data comp1 = program.getListing().getDataContaining(addr).getComponent(fromPath);
DataType parent = comp1.getParent().getBaseDataType();
if (!(parent instanceof Structure)) {
    // do not invoke CreateStructureInStructureCmd
}

boolean isInsideStructure(Program p, Address addr, int[] fromPath) {
    Data comp = p.getListing().getDataContaining(addr).getComponent(fromPath);
    return comp != null && comp.getParent() != null
        && comp.getParent().getBaseDataType() instanceof Structure;
}

try {
    cmd.applyTo(program);
} catch (IllegalArgumentException e) {
    if ("Data not in a structure".equals(e.getMessage())) {
        // user selected a Union/other composite; inform and abort
    } else throw e;
}

When it happens

Trigger: Invoking CreateStructureInStructureCmd on a component whose parent is a Union (or other non-Structure composite). The fromPath/toPath must select components inside a Structure; using them against a Union's members violates the precondition.

Common situations: User selects a field inside a Union and runs 'Create Structure' in Ghidra. Programmatic use of CreateStructureInStructureCmd with a fromPath rooted in a non-Structure. Path computed against a Typedef that resolves to a Union.

Related errors

• Null datatype passed to getIsfObject
• Can't create structure because length exceeds address space
• Invalid number of elements specified: {}
• pos cannot be less than zero
• %s: unknown demangling style `%s'

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/e097254a479eb8d6. Report an issue: GitHub.