Fix hot file replication by handling null criteria in PSU match

modules/dcache/src/main/java/diskCacheV111/poolManager/LinkMap.java

@@ -1,19 +1,18 @@
 package diskCacheV111.poolManager;
 
-import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.Iterator;
-import java.util.List;
 import java.util.Map;
 
 class LinkMap {
 
-    private static class LinkMapEntry {
+    static class LinkMapEntry {
 
-        private final Link _link;
-        private int _counter;
+        final Link _link;
+        int _counter;
 
-        private LinkMapEntry(Link link) {
+        LinkMapEntry(Link link) {
             _link = link;
             _counter = link._uGroupList.size() - 1;
         }
@@ -37,4 +36,7 @@ void addLink(Link link) {
         }
     }
 
+    Collection<LinkMapEntry> entries() {
+        return _linkHash.values();
+    }
 }

modules/dcache/src/main/java/diskCacheV111/poolManager/PoolSelectionUnitV2.java

@@ -703,7 +703,8 @@ public PoolPreferenceLevel[] match(DirectionType type, String netUnitName,
             addNetUnit(units, netUnitName);
 
             LinkGroup linkGroup = resolveLinkGroup(linkGroupName);
-            Set<Link> sortedSet = findMatchingLinks(units, linkGroup, type);
+            Set<Link> sortedSet = findMatchingLinks(units, linkGroup, type,
+                  protocolUnitName == null, netUnitName == null);
 
             List<List<Link>> linkLists = matchPreferences(type, sortedSet);
             result = buildPreferenceLevels(type, linkLists, fileAttributes, exclude);
@@ -848,18 +849,28 @@ private LinkGroup resolveLinkGroup(String linkGroupName) {
     }
 
     private Set<Link> findMatchingLinks(List<Unit> units, LinkGroup linkGroup,
-          DirectionType type) {
+          DirectionType type, boolean ignoreProtocol, boolean ignoreNet) {
         Set<Link> sortedSet = new TreeSet<>(new LinkComparator(type));
         LinkMap matchingLinks = new LinkMap();
-        int fitCount = units.size();
         for (Unit unit : units) {
             matchingLinks = match(matchingLinks, unit, linkGroup, type);
         }
 
-        Iterator<Link> linkIterator = matchingLinks.iterator();
-        while (linkIterator.hasNext()) {
-            Link link = linkIterator.next();
-            if (link._uGroupList.size() <= fitCount) {
+        for (LinkMap.LinkMapEntry entry : matchingLinks.entries()) {
+            Link link = entry._link;
+            int ignored = 0;
+            if (ignoreProtocol || ignoreNet) {
+                for (UGroup uGroup : link._uGroupList.values()) {
+                    UnitType groupType = uGroup._unitList.values().stream()
+                          .findFirst().map(Unit::getType).orElse(null);
+                    if ((ignoreProtocol && groupType == PROTOCOL)
+                          || (ignoreNet && groupType == NET)) {
+                        entry._counter--;
+                        ignored++;
+                    }
+                }
+            }
+            if (entry._counter <= 0 && link._uGroupList.size() <= units.size() + ignored) {
                 sortedSet.add(link);
             }
         }

modules/dcache/src/test/java/diskCacheV111/poolManager/PoolSelectionUnitV2Test.java

@@ -443,4 +443,17 @@ private void whenMatchIsCalledWith(String params) {
             assertNull("Unexpected exception", e);
         }
     }
+
+    /**
+     * Regression test for hot file replication issue introduced in 96c4db4f8b.
+     * When protocol and network are null, they should match any protocol or network requirement
+     * of a link.
+     */
+    @Test
+    public void testThatReadWithNullProtocolAndNetMatchesTapePools() {
+        diskCacheV111.vehicles.StorageInfo storageInfo = diskCacheV111.vehicles.GenericStorageInfo.valueOf("tape.dcache-devel-test@enstore", "*");
+        org.dcache.vehicles.FileAttributes fileAttributes = org.dcache.vehicles.FileAttributes.ofStorageInfo(storageInfo);
+        levels = psu.match(PoolSelectionUnit.DirectionType.READ, null, null, fileAttributes, null, p -> false);
+        assertThatPoolsAre(TAPE_POOLS);
+    }
 }