GH-5053: avoid log spam for configurations class with legacy settings (#5077)

Author: aschwarte10

core/model/src/main/java/org/eclipse/rdf4j/model/util/Configurations.java

@@ -165,7 +165,13 @@ public static Set<Value> getPropertyValues(Model model, Resource subject, IRI pr
 		var fallbackObjects = model.filter(subject, fallbackProperty, null).objects();
 
 		if (!fallbackObjects.isEmpty() && !preferredObjects.equals(fallbackObjects)) {
-			logger.warn("Discrepancy between use of the old and new config vocabulary.");
+			var msg = "Discrepancy between use of the old and new config vocabulary.";
+			// depending on whether preferred is set, we log on warn or debug
+			if (preferredObjects.isEmpty()) {
+				logger.debug(msg);
+			} else {
+				logger.warn(msg);
+			}
 
 			if (preferredObjects.containsAll(fallbackObjects)) {
 				return preferredObjects;
@@ -235,7 +241,13 @@ public static Optional<Resource> getSubjectByType(Model model, IRI type, IRI leg
 	private static void logDiscrepancyWarning(Optional<? extends Value> preferred,
 			Optional<? extends Value> fallback) {
 		if (!fallback.isEmpty() && !preferred.equals(fallback)) {
-			logger.warn("Discrepancy between use of the old and new config vocabulary.");
+			var msg = "Discrepancy between use of the old and new config vocabulary.";
+			// depending on whether preferred is set, we log on warn or debug
+			if (preferred.isEmpty()) {
+				logger.debug(msg);
+			} else {
+				logger.warn(msg);
+			}
 		}
 	}
 }

core/model/src/test/java/org/eclipse/rdf4j/model/util/ConfigurationsTest.java

@@ -101,6 +101,7 @@ public void testGetLiteralValue_no_discrepancy() {
 		var result = Configurations.getLiteralValue(m, subject, RDFS.LABEL, RDFS.COMMENT);
 		assertThat(result).contains(literal("label"));
 		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.WARN);
+		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.DEBUG);
 	}
 
 	@Test
@@ -116,7 +117,21 @@ public void testGetLiteralValue_useLegacy_onlyNew() {
 		System.setProperty("org.eclipse.rdf4j.model.vocabulary.useLegacyConfig", "");
 
 		assertThat(result).contains(literal("label"));
-		assertLogged("Discrepancy between use of the old and new config vocabulary.", Level.WARN);
+		assertLogged("Discrepancy between use of the old and new config vocabulary.", Level.DEBUG);
+	}
+
+	@Test
+	public void testGetLiteralValue_onlyLegacy() {
+
+		var subject = bnode();
+		var m = new ModelBuilder().subject(subject)
+				.add(RDFS.COMMENT, "comment")
+				.build();
+
+		var result = Configurations.getLiteralValue(m, subject, RDFS.LABEL, RDFS.COMMENT);
+
+		assertThat(result).contains(literal("comment"));
+		assertLogged("Discrepancy between use of the old and new config vocabulary.", Level.DEBUG);
 	}
 
 	@Test
@@ -158,6 +173,7 @@ public void testGetResourceValue_no_discrepancy() {
 		var result = Configurations.getResourceValue(m, subject, RDFS.LABEL, RDFS.COMMENT);
 		assertThat(result).contains(iri("urn:label"));
 		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.WARN);
+		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.DEBUG);
 	}
 
 	@Test
@@ -183,6 +199,7 @@ public void testGetIRIValue_no_discrepancy() {
 		var result = Configurations.getIRIValue(m, subject, RDFS.LABEL, RDFS.COMMENT);
 		assertThat(result).contains(iri("urn:label"));
 		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.WARN);
+		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.DEBUG);
 	}
 
 	@Test
@@ -197,6 +214,7 @@ public void testGetPropertyValues_no_legacy() {
 		var result = Configurations.getPropertyValues(m, subject, RDFS.LABEL, RDFS.COMMENT);
 		assertThat(result).hasSize(2);
 		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.WARN);
+		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.DEBUG);
 	}
 
 	@Test
@@ -213,6 +231,7 @@ public void testGetPropertyValues_no_discrepancy() {
 		var result = Configurations.getPropertyValues(m, subject, RDFS.LABEL, RDFS.COMMENT);
 		assertThat(result).hasSize(2);
 		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.WARN);
+		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.DEBUG);
 	}
 
 	@Test
@@ -229,6 +248,7 @@ public void testGetPropertyValues_useLegacy_no_discrepancy() {
 		var result = Configurations.getPropertyValues(m, subject, RDFS.LABEL, RDFS.COMMENT);
 		assertThat(result).hasSize(2);
 		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.WARN);
+		assertNotLogged("Discrepancy between use of the old and new config vocabulary.", Level.DEBUG);
 	}
 
 	@Test