Fix BF skipper handling of version-range candidates

maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/collect/bf/DependencyResolutionSkipper.java

@@ -250,6 +250,12 @@ private CacheManager(Function<Artifact, String> keyFunction) {
             }
 
             boolean isVersionConflict(DependencyNode node) {
+                if (isRangeDependency(node)) {
+                    // A version range can select a different version than one already seen. Resolve it so its
+                    // dependencies are available to the conflict resolver.
+                    return false;
+                }
+
                 String ga = keyFunction.apply(node.getArtifact());
                 if (winnerGAs.containsKey(ga)) {
                     Artifact result = winnerGAs.get(ga);
@@ -261,12 +267,20 @@ boolean isVersionConflict(DependencyNode node) {
 
             void cacheWinner(DependencyNode node) {
                 winners.put(node.getArtifact(), node);
-                winnerGAs.put(keyFunction.apply(node.getArtifact()), node.getArtifact());
+                // A range candidate is not a reliable winner for the versionless key.
+                if (!isRangeDependency(node)) {
+                    winnerGAs.put(keyFunction.apply(node.getArtifact()), node.getArtifact());
+                }
             }
 
             boolean isDuplicate(DependencyNode node) {
                 return winners.containsKey(node.getArtifact());
             }
+
+            private static boolean isRangeDependency(DependencyNode node) {
+                return node.getVersionConstraint() != null
+                        && node.getVersionConstraint().getRange() != null;
+            }
         }
 
         private static final class CoordinateManager {

maven-resolver-impl/src/test/java/org/eclipse/aether/internal/impl/collect/bf/BfWithSkipperDependencyCollectorTest.java

@@ -140,6 +140,26 @@ void testPoolCacheTransparencyWithTransitiveDependencyManager() throws Dependenc
                 "c under b-alt should have d as a child");
     }
 
+    @Test
+    void testVersionRangeCandidateDependenciesAreNotSkipped() throws DependencyCollectionException {
+        collector = setupCollector(newReader("maven13430/"));
+
+        CollectResult result = collector.collectDependencies(
+                session,
+                new CollectRequest(newDep("maven13430:root:ext:1", "compile"), Collections.singletonList(repository)));
+
+        assertEquals(0, result.getExceptions().size());
+
+        DependencyNode rangeCandidate = path(result.getRoot(), 0, 0);
+        assertEquals("library", rangeCandidate.getArtifact().getArtifactId());
+        assertEquals("3", rangeCandidate.getArtifact().getVersion());
+        assertTrue(
+                rangeCandidate.getChildren().stream()
+                        .anyMatch(
+                                node -> "range-asset".equals(node.getArtifact().getArtifactId())),
+                "dependencies of the resolved version-range candidate must be collected");
+    }
+
     @Test
     void testSkipperWithDifferentExclusion() throws DependencyCollectionException {
         collector = setupCollector(newReader("managed/"));

maven-resolver-impl/src/test/java/org/eclipse/aether/internal/impl/collect/bf/DependencyResolutionSkipperTest.java

@@ -30,6 +30,7 @@
 import org.eclipse.aether.graph.DependencyNode;
 import org.eclipse.aether.internal.test.util.TestVersion;
 import org.eclipse.aether.internal.test.util.TestVersionConstraint;
+import org.eclipse.aether.util.version.GenericVersionScheme;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.*;
@@ -101,6 +102,29 @@ void testSkipVersionConflict() {
         }
     }
 
+    @Test
+    void testVersionRangeDoesNotReplaceVersionlessWinner() throws Exception {
+        DependencyNode pinned = makeDependencyNode("some-group", "A", "1.0");
+        DefaultDependencyNode ranged = (DefaultDependencyNode) makeDependencyNode("some-group", "A", "3.0");
+        ranged.setVersionConstraint(new GenericVersionScheme().parseVersionConstraint("[2.0,4.0)"));
+        DependencyNode pinnedAgain = makeDependencyNode("some-group", "A", "1.0");
+
+        try (DependencyResolutionSkipper.DefaultDependencyResolutionSkipper skipper =
+                DependencyResolutionSkipper.defaultGACESkipper()) {
+            assertFalse(skipper.skipResolution(pinned, new ArrayList<>()));
+            skipper.cache(pinned, new ArrayList<>());
+
+            assertFalse(skipper.skipResolution(ranged, new ArrayList<>()));
+            skipper.cache(ranged, new ArrayList<>());
+
+            assertTrue(skipper.skipResolution(pinnedAgain, new ArrayList<>()));
+            DependencyResolutionSkipper.DependencyResolutionResult result =
+                    skipper.getResults().get(pinnedAgain);
+            assertTrue(result.skippedAsDuplicate);
+            assertFalse(result.skippedAsVersionConflict);
+        }
+    }
+
     @Test
     void testSkipDeeperDuplicateNode() {
         // A -> B

maven-resolver-impl/src/test/resources/artifact-descriptions/maven13430/maven13430_library_1.ini

@@ -0,0 +1 @@
+[dependencies]

maven-resolver-impl/src/test/resources/artifact-descriptions/maven13430/maven13430_library_2.ini

@@ -0,0 +1 @@
+[dependencies]

maven-resolver-impl/src/test/resources/artifact-descriptions/maven13430/maven13430_library_3.ini

@@ -0,0 +1,2 @@
+[dependencies]
+maven13430:range-asset:ext:1

maven-resolver-impl/src/test/resources/artifact-descriptions/maven13430/maven13430_parent_1.ini

@@ -0,0 +1,2 @@
+[dependencies]
+maven13430:library:ext:[2,4)

maven-resolver-impl/src/test/resources/artifact-descriptions/maven13430/maven13430_range-asset_1.ini

@@ -0,0 +1 @@
+[dependencies]

maven-resolver-impl/src/test/resources/artifact-descriptions/maven13430/maven13430_root_1.ini

@@ -0,0 +1,3 @@
+[dependencies]
+maven13430:parent:ext:1
+maven13430:library:ext:1