HBASE-29706: Make CoprocessorDescriptorImpl.equals() and hashCode() robust

Author: mnpoonia

hbase-client/src/main/java/org/apache/hadoop/hbase/client/CoprocessorDescriptorBuilder.java

@@ -111,5 +111,28 @@ public String toString() {
       return "class:" + className + ", jarPath:" + jarPath + ", priority:" + priority
         + ", properties:" + properties;
     }
+
+    @Override
+    public boolean equals(Object obj) {
+      if (this == obj) {
+        return true;
+      }
+      if (obj == null || !(obj instanceof CoprocessorDescriptor)) {
+        return false;
+      }
+      CoprocessorDescriptor other = (CoprocessorDescriptor) obj;
+      if (
+        priority != other.getPriority() || !Objects.equals(className, other.getClassName())
+          || !Objects.equals(getJarPath(), other.getJarPath())
+      ) {
+        return false;
+      }
+      return new TreeMap<>(getProperties()).equals(new TreeMap<>(other.getProperties()));
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(className, jarPath, priority, new TreeMap<>(properties));
+    }
   }
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/ModifyTableProcedure.java

@@ -133,8 +133,8 @@ protected void preflightChecks(MasterProcedureEnv env, Boolean enabled) throws H
           "Cannot add or remove column families when this modification " + "won't reopen regions.");
       }
       if (
-        this.unmodifiedTableDescriptor.getCoprocessorDescriptors().hashCode()
-            != this.modifiedTableDescriptor.getCoprocessorDescriptors().hashCode()
+        !new HashSet<>(this.unmodifiedTableDescriptor.getCoprocessorDescriptors())
+            .equals(new HashSet<>(this.modifiedTableDescriptor.getCoprocessorDescriptors()))
       ) {
         throw new HBaseIOException(
           "Can not modify Coprocessor when table modification won't reopen regions");

hbase-server/src/test/java/org/apache/hadoop/hbase/master/procedure/TestModifyTableProcedure.java

@@ -35,6 +35,7 @@
 import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.client.TableDescriptor;
 import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
+import org.apache.hadoop.hbase.coprocessor.SimpleRegionObserver;
 import org.apache.hadoop.hbase.io.compress.Compression;
 import org.apache.hadoop.hbase.master.procedure.MasterProcedureTestingUtility.StepHook;
 import org.apache.hadoop.hbase.procedure2.Procedure;
@@ -698,4 +699,75 @@ public void testModifyWillNotReopenRegions() throws IOException {
       assertTrue(e.getMessage().contains("Can not modify REGION_REPLICATION"));
     }
   }
+
+  @Test
+  public void testModifyTableWithCoprocessorAndColumnFamilyPropertyChange() throws IOException {
+    // HBASE-29706 - This test validates the fix for the bug where modifying only column family properties
+    // (like COMPRESSION) with REOPEN_REGIONS=false would incorrectly throw an error when
+    // coprocessors are present. The bug was caused by comparing collection hash codes
+    // instead of actual descriptor content, which failed when HashMap iteration order varied.
+
+    final boolean reopenRegions = false;
+    final TableName tableName = TableName.valueOf(name.getMethodName());
+    final ProcedureExecutor<MasterProcedureEnv> procExec = getMasterProcedureExecutor();
+
+    MasterProcedureTestingUtility.createTable(procExec, tableName, null, "cf");
+
+    // Step 1: Add a coprocessor to the table
+    TableDescriptor htd = UTIL.getAdmin().getDescriptor(tableName);
+    TableDescriptor descriptorWithCoprocessor = TableDescriptorBuilder.newBuilder(htd)
+      .setCoprocessor(CoprocessorDescriptorBuilder
+        .newBuilder(SimpleRegionObserver.class.getName())
+        .setPriority(100)
+        .build())
+      .build();
+    long procId = ProcedureTestingUtility.submitAndWait(procExec, new ModifyTableProcedure(
+      procExec.getEnvironment(), descriptorWithCoprocessor, null, htd, false, true));
+    ProcedureTestingUtility.assertProcNotFailed(procExec.getResult(procId));
+
+    // Verify coprocessor was added
+    TableDescriptor currentHtd = UTIL.getAdmin().getDescriptor(tableName);
+    assertEquals(1, currentHtd.getCoprocessorDescriptors().size());
+
+    // Step 2: Modify only the column family property (COMPRESSION) with REOPEN_REGIONS=false
+    // This should SUCCEED because we're not actually modifying the coprocessor,
+    // just the column family compression setting.
+    htd = UTIL.getAdmin().getDescriptor(tableName);
+    TableDescriptor modifiedDescriptor = TableDescriptorBuilder.newBuilder(htd)
+      .modifyColumnFamily(ColumnFamilyDescriptorBuilder
+        .newBuilder("cf".getBytes())
+        .setCompressionType(Compression.Algorithm.SNAPPY)
+        .build())
+      .build();
+
+    // This should NOT throw an error - the fix ensures order-independent coprocessor comparison
+    long procId2 = ProcedureTestingUtility.submitAndWait(procExec, new ModifyTableProcedure(
+      procExec.getEnvironment(), modifiedDescriptor, null, htd, false, reopenRegions));
+    ProcedureTestingUtility.assertProcNotFailed(procExec.getResult(procId2));
+
+    // Verify the modification succeeded
+    currentHtd = UTIL.getAdmin().getDescriptor(tableName);
+    assertEquals("Coprocessor should still be present", 1,
+      currentHtd.getCoprocessorDescriptors().size());
+    assertEquals("Compression should be updated in table descriptor", Compression.Algorithm.SNAPPY,
+      currentHtd.getColumnFamily("cf".getBytes()).getCompressionType());
+
+    // Verify regions haven't picked up the change yet (since reopenRegions=false)
+    for (HRegion r : UTIL.getHBaseCluster().getRegions(tableName)) {
+      assertEquals("Regions should still have old compression", Compression.Algorithm.NONE,
+        r.getTableDescriptor().getColumnFamily("cf".getBytes()).getCompressionType());
+    }
+
+    // Force regions to reopen
+    for (HRegion r : UTIL.getHBaseCluster().getRegions(tableName)) {
+      getMaster().getAssignmentManager().move(r.getRegionInfo());
+    }
+
+    // After reopen, regions should have the new compression setting
+    for (HRegion r : UTIL.getHBaseCluster().getRegions(tableName)) {
+      assertEquals("Regions should now have new compression after reopen",
+        Compression.Algorithm.SNAPPY,
+        r.getTableDescriptor().getColumnFamily("cf".getBytes()).getCompressionType());
+    }
+  }
 }