junit-team/junit5 · error · PreconditionViolationException

Failed to create a java.net.URI from

Error message

Failed to create a java.net.URI from: ${uri}

What it means

DiscoverySelectors.selectUri(String) constructs a java.net.URI from a string; if the string violates RFC 3986 (URISyntaxException), it is wrapped as PreconditionViolationException. The string must already be non-blank (checked just before). This guards selector construction before any discovery runs.

Solutions

1. Use java.net.URI or URI.Builder/Path.toUri() to construct the string rather than concatenation, so encoding is handled.
2. Percent-encode spaces and reserved characters; ensure a scheme is present (e.g. 'file://', 'http://').
3. Prefer selectUri(URI) overload (passing a pre-built URI) to surface syntax errors at construction time near the source.
4. Inspect URISyntaxException position from the cause to locate the bad character.

Example fix

// before
UriSelector s = selectUri("my file path with spaces.xml");
// after
UriSelector s = selectUri(new File("my file path with spaces.xml").toURI().toString());
// or
UriSelector s = selectUri(new URI("file", null, "/my%20file%20path.xml", null));

// Validate URI syntax before constructing the selector.
String uriStr = userInput;
try { new java.net.URI(uriStr); } catch (java.net.URISyntaxException e) {
  throw new IllegalArgumentException("Invalid URI for selectUri: " + e.getMessage(), e);
}
// or use a real URI directly

try { return selectUri(new URI(raw)); } catch (URISyntaxException e) { /* convert/escape or ask caller to fix */ }

When it happens

Trigger: Calling selectUri(string) with a syntactically invalid URI: missing scheme, illegal characters (spaces, unencoded brackets), a path needing percent-encoding, or a malformed authority. URISyntaxException's reason points at the offending position.

Common situations: Passing a file path with spaces as a URI without percent-encoding; missing scheme ('host/path' instead of 'file://...'); copy-pasted URIs with stray characters; building URIs by string concatenation without URI-building utilities.

Related errors

• Could not find any resource(s) with name
• Failed to retrieve canonical path for directory
• Failed to retrieve canonical path for file
• OutputDirectoryCreator not available; probably due to…
• ' ' is not a well-formed UniqueId segment

AI-assisted analysis of junit-team/junit5@f070c699a0 (2026-08-11). Data as JSON: /api/errors/385dbbe6e004900d. Report an issue: GitHub.

Appendix: source

Thrown at junit-platform-engine/src/main/java/org/junit/platform/engine/discovery/DiscoverySelectors.java:86

	/**
	 * Create a {@code UriSelector} for the supplied URI.
	 *
	 * @param uri the URI to select; never {@code null} or blank
	 * @see UriSelector
	 * @see #selectUri(URI)
	 * @see #selectFile(String)
	 * @see #selectFile(File)
	 * @see #selectDirectory(String)
	 * @see #selectDirectory(File)
	 */
	public static UriSelector selectUri(String uri) {
		Preconditions.notBlank(uri, "URI must not be null or blank");
		try {
			return new UriSelector(new URI(uri));
		}
		catch (URISyntaxException ex) {
			throw new PreconditionViolationException("Failed to create a java.net.URI from: " + uri, ex);
		}
	}

	/**
	 * Create a {@code UriSelector} for the supplied {@link URI}.
	 *
	 * @param uri the URI to select; never {@code null}
	 * @see UriSelector
	 * @see #selectUri(String)
	 * @see #selectFile(String)
	 * @see #selectFile(File)
	 * @see #selectDirectory(String)
	 * @see #selectDirectory(File)
	 */
	public static UriSelector selectUri(URI uri) {
		Preconditions.notNull(uri, "URI must not be null");
		return new UriSelector(uri);
	}

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