GH-5407 Turtle: treat '.' at EOF as statement terminator after digits; fix integer literal-at-EOF parsing

Author: hmottestad

core/rio/turtle/src/main/java/org/eclipse/rdf4j/rio/turtle/TurtleParser.java

@@ -808,7 +808,11 @@ protected Literal parseNumber() throws IOException, RDFParseException {
 			// read optional fractional digits
 			if (c == '.') {
 
-				if (TurtleUtil.isWhitespace(peekCodePoint())) {
+				int next = peekCodePoint();
+				// Treat '.' as statement terminator at EOF only when we already parsed at least one digit
+				// (e.g., "30.") or when whitespace follows. Otherwise, attempt to parse as decimal
+				// which will surface a useful error for a stray '.' token.
+				if ((value.length() > 0 && next == -1) || TurtleUtil.isWhitespace(next)) {
 					// We're parsing an integer that did not have a space before
 					// the
 					// period to end the statement

core/rio/turtle/src/test/java/org/eclipse/rdf4j/rio/turtle/TurtleParserTest.java

@@ -110,6 +110,26 @@ public void testIntegerFollowedByDotAtEOF() throws IOException {
 		assertEquals(XSD.INTEGER, lit.getDatatype());
 	}
 
+	@Test
+	public void testLetterFollowedByDotAtEOF() throws IOException {
+		String data = prefixes + ":alice :age \"a\"."; // no trailing whitespace/newline
+
+		parser.parse(new StringReader(data), baseURI);
+
+		assertTrue(errorCollector.getWarnings().isEmpty());
+		assertTrue(errorCollector.getErrors().isEmpty());
+		assertTrue(errorCollector.getFatalErrors().isEmpty());
+
+		assertEquals(1, statementCollector.getStatements().size());
+		Statement st = statementCollector.getStatements().iterator().next();
+		assertEquals(vf.createIRI("http://example.org/alice"), st.getSubject());
+		assertEquals(vf.createIRI("http://example.org/age"), st.getPredicate());
+		assertTrue(st.getObject() instanceof Literal);
+		Literal lit = (Literal) st.getObject();
+		assertEquals("a", lit.getLabel());
+		assertEquals(XSD.STRING, lit.getDatatype());
+	}
+
 	@Test
 	public void testParseIllegalURIFatal() throws IOException {
 		String data = " <urn:foo_bar\\r> <urn:foo> <urn:bar> ; <urn:foo2> <urn:bar2> . <urn:foobar> <urn:food> <urn:barf> . ";