junit-team/junit5 · error · ExtensionConfigurationException

Failed to create default temp directory

Error message

Failed to create default temp directory

What it means

Thrown by TempDirectory.createTempDir() when constructing a CloseablePath (which calls the configured TempDirFactory.createTempDirectory()) raises any Exception. The factory default uses Files.createTempDirectory(), so failures typically stem from the underlying filesystem; the engine wraps the cause in an ExtensionConfigurationException.

Source

Thrown at junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/extension/TempDirectory.java:241

			TempDirFactory factory, Cleanup cleanup, ExtensionContext extensionContext) {

		Path path = extensionContext.getStore(NAMESPACE.append(elementContext)) //
				.computeIfAbsent(KEY,
					__ -> createTempDir(factory, cleanup, elementType, elementContext, extensionContext),
					CloseablePath.class) //
				.get();

		return (elementType == Path.class) ? path : path.toFile();
	}

	static CloseablePath createTempDir(TempDirFactory factory, Cleanup cleanup, Class<?> elementType,
			AnnotatedElementContext elementContext, ExtensionContext extensionContext) {

		try {
			return new CloseablePath(factory, cleanup, elementType, elementContext, extensionContext);
		}
		catch (Exception ex) {
			throw new ExtensionConfigurationException("Failed to create default temp directory", ex);
		}
	}

	private static boolean selfOrChildFailed(ExtensionContext context) {
		return context.getExecutionException().isPresent() //
				|| getContextSpecificStore(context).getOrDefault(CHILD_FAILED, Boolean.class, false);
	}

	private static ExtensionContext.Store getContextSpecificStore(ExtensionContext context) {
		return context.getStore(NAMESPACE.append(context));
	}

	@SuppressWarnings("deprecation")
	static class CloseablePath implements Store.CloseableResource, AutoCloseable {

		private final @Nullable Path dir;
		private final TempDirFactory factory;
		private final Cleanup cleanup;

View on GitHub (pinned to 956246301e)

Solutions

1. Inspect the cause Exception for the exact I/O error and path.
2. Ensure java.io.tmpdir (or your factory's base) is writable and has free space; on CI, set -Djava.io.tmpdir to a writable volume.
3. If using a custom @TempDir(factory = MyFactory.class), debug MyFactory.createTempDirectory in isolation and ensure it creates the directory and all missing parents.
4. Clean up leaked temp dirs from prior runs that may have exhausted inodes/space.

Example fix

// before — custom factory points at a non-writable root
class MyFactory implements TempDirFactory {
    public Path createTempDirectory(AnnotatedElementContext c, ExtensionContext ec) throws Exception {
        return Files.createDirectory(Path.of("/opt/readonly/junit-" + System.nanoTime()));
    }
}
// after
class MyFactory implements TempDirFactory {
    public Path createTempDirectory(AnnotatedElementContext c, ExtensionContext ec) throws Exception {
        Path base = Path.of(System.getProperty("java.io.tmpdir"), "junit");
        Files.createDirectories(base);
        return Files.createTempDirectory(base, "test-");
    }
}

// Ensure the temp dir base is writable before launch
Path tmp = Path.of(System.getProperty("java.io.tmpdir"));
if (!Files.isWritable(tmp)) throw new IllegalStateException("tmpdir not writable: " + tmp);
try { Path probe = Files.createTempDirectory(tmp, "probe-"); Files.delete(probe); }
catch (IOException e) { throw new IllegalStateException("Cannot create temp dir under " + tmp, e); }

When it happens

Trigger: A custom @TempDir(factory = ...) whose createTempDirectory() throws, or the default factory failing because the java.io.tmpdir is full, read-only, or the process lacks permission to create a directory there.

Common situations: CI runners with a full /tmp; containers mounted with a read-only tmpfs; a custom TempDirFactory that creates dirs under a configured root that does not exist or is unwritable; disk quota exceeded.

Related errors

• temp directory must be a directory
• temp directory with non-default file system cannot be inject
• Failed to copy files to the output directory
• Failed to publish path
• Failed to create output directory

AI-assisted analysis of junit-team/junit5@956246301e (2026-08-04). Data as JSON: /data/errors/d48739d56e2cdb22.json. Report an issue: GitHub.