NationalSecurityAgency/ghidra · critical · IOException

Failed to find the module's jython-src directory

Error message

Failed to find the module's jython-src directory

What it means

Thrown by JythonUtils.setupJythonCacheDir() when the module's jython-src directory cannot be found. It first checks <moduleRoot>/jython-src, and if absent tries Application.getModuleDataSubDirectory(moduleName, 'jython-src'); a FileNotFoundException from that lookup triggers this IOException. The source .py files to seed the cache are therefore missing.

Source

Thrown at Ghidra/Extensions/Jython/src/main/java/ghidra/jython/JythonUtils.java:89

		if (!FileUtilities.mkdirs(cacheDir)) {
			throw new IOException("Failed to create the jython cache directory at: " + cacheDir);
		}

		File jythonSrcDestDir = new File(cacheDir, JYTHON_SRC);
		if (!FileUtilities.createDir(jythonSrcDestDir)) {
			throw new IOException(
				"Failed to create the " + JYTHON_SRC + " directory at: " + jythonSrcDestDir);
		}

		File jythonModuleDir = Application.getMyModuleRootDirectory().getFile(false);
		File jythonSrcDir = new File(jythonModuleDir, JYTHON_SRC);
		if (!jythonSrcDir.exists()) {
			try {
				jythonSrcDir = Application.getModuleDataSubDirectory(jythonModuleDir.getName(),
					JYTHON_SRC).getFile(false);
			}
			catch (FileNotFoundException e) {
				throw new IOException("Failed to find the module's " + JYTHON_SRC + " directory");
			}
		}

		try {
			FileUtilities.copyDir(jythonSrcDir, jythonSrcDestDir, f -> f.getName().endsWith(".py"),
				monitor);
		}
		catch (IOException e) {
			throw new IOException(
				"Failed to copy " + JYTHON_SRC + " files to: " + jythonSrcDestDir);
		}

		System.setProperty("python.cachedir.skip", "false");
		System.setProperty("python.cachedir", cacheDir.getAbsolutePath());
		System.setProperty("python.path", jythonSrcDestDir.getAbsolutePath());

		return cacheDir;
	}

View on GitHub (pinned to d5f144c24d)

Solutions

1. Reinstall/repair the Jython extension so its module data contains jython-src.
2. In dev mode, run the module data build/copy task to populate jython-src under the module.
3. Confirm Application.getMyModuleRootDirectory() points at the Jython module and that its data subdirectory is intact.

Example fix

null

import java.io.File;
File moduleRoot = Application.getMyModuleRootDirectory().getFile(false);
File src = new File(moduleRoot, "jython-src");
if (!src.exists()) {
    // module data missing jython-src; repair/extend before interpreter init
}

null

try {
    GhidraJythonInterpreter.get();
} catch (NullPointerException npe) {
    // get() swallowed the IOException and returned null; verify module data
}

When it happens

Trigger: Interpreter init where the Jython extension module data did not include the jython-src tree — e.g. a partial install where jython-2.7.4 home exists but the source bundle was not laid down, or a dev build that skipped copying jython-src.

Common situations: Trimmed/custom distribution that shipped the Jython home but not jython-src; a module layout change after upgrade; an extension rebuild that omitted the data copy step.

Related errors

• Failed to find the jython home directory at: {jythonHomeDir}
• Cannot find Python source for {name}. If this is a remote s
• Failed to create the jython cache directory at: {cacheDir}
• Failed to create the jython-src directory at: {jythonSrcDest
• Failed to copy jython-src files to: {jythonSrcDestDir}

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/967fc3d8e7f7b7f2. Report an issue: GitHub.