incorporate changes

Author: rahul2393

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionProperties.java

@@ -456,7 +456,9 @@ public class ConnectionProperties {
           ENABLE_DYNAMIC_CHANNEL_POOL_PROPERTY_NAME,
           "Enable dynamic channel pooling for automatic gRPC channel scaling. When enabled, the "
               + "client will automatically scale the number of channels based on load. Setting "
-              + "numChannels will disable dynamic channel pooling even if this is set to true.",
+              + "numChannels will disable dynamic channel pooling even if this is set to true. "
+              + "The default is currently false (disabled), but this may change to true in a "
+              + "future version. Set this property explicitly to ensure consistent behavior.",
           DEFAULT_ENABLE_DYNAMIC_CHANNEL_POOL,
           BOOLEANS,
           BooleanConverter.INSTANCE,

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SpannerPool.java

@@ -421,40 +421,48 @@ Spanner createSpanner(SpannerPoolKey key, ConnectionOptions options) {
     if (key.numChannels != null) {
       builder.setNumChannels(key.numChannels);
     }
-    // Configure Dynamic Channel Pooling (DCP) if enabled.
+    // Configure Dynamic Channel Pooling (DCP) based on explicit user setting.
     // Note: Setting numChannels disables DCP even if enableDynamicChannelPool is true.
-    if (Boolean.TRUE.equals(key.enableDynamicChannelPool) && key.numChannels == null) {
-      builder.enableDynamicChannelPool();
-      // Build custom GcpChannelPoolOptions if any DCP-specific options are set.
-      if (key.dcpMinChannels != null
-          || key.dcpMaxChannels != null
-          || key.dcpInitialChannels != null) {
-        // Build GcpChannelPoolOptions from scratch with custom values or Spanner defaults.
-        int minChannels =
-            key.dcpMinChannels != null
-                ? key.dcpMinChannels
-                : SpannerOptions.DEFAULT_DYNAMIC_POOL_MIN_CHANNELS;
-        int maxChannels =
-            key.dcpMaxChannels != null
-                ? key.dcpMaxChannels
-                : SpannerOptions.DEFAULT_DYNAMIC_POOL_MAX_CHANNELS;
-        int initChannels =
-            key.dcpInitialChannels != null
-                ? key.dcpInitialChannels
-                : SpannerOptions.DEFAULT_DYNAMIC_POOL_INITIAL_SIZE;
-        GcpChannelPoolOptions poolOptions =
-            GcpChannelPoolOptions.newBuilder()
-                .setMinSize(minChannels)
-                .setMaxSize(maxChannels)
-                .setInitSize(initChannels)
-                .setDynamicScaling(
-                    SpannerOptions.DEFAULT_DYNAMIC_POOL_MIN_RPC,
-                    SpannerOptions.DEFAULT_DYNAMIC_POOL_MAX_RPC,
-                    SpannerOptions.DEFAULT_DYNAMIC_POOL_SCALE_DOWN_INTERVAL)
-                .setAffinityKeyLifetime(SpannerOptions.DEFAULT_DYNAMIC_POOL_AFFINITY_KEY_LIFETIME)
-                .setCleanupInterval(SpannerOptions.DEFAULT_DYNAMIC_POOL_CLEANUP_INTERVAL)
-                .build();
-        builder.setGcpChannelPoolOptions(poolOptions);
+    if (key.enableDynamicChannelPool != null && key.numChannels == null) {
+      if (Boolean.TRUE.equals(key.enableDynamicChannelPool)) {
+        builder.enableDynamicChannelPool();
+        // Build custom GcpChannelPoolOptions if any DCP-specific options are set.
+        if (key.dcpMinChannels != null
+            || key.dcpMaxChannels != null
+            || key.dcpInitialChannels != null) {
+          // Build GcpChannelPoolOptions from scratch with custom values or Spanner defaults.
+          // Note: GcpChannelPoolOptions does not have a toBuilder() method, so we must
+          // construct from scratch using SpannerOptions defaults for unspecified values.
+          int minChannels =
+              key.dcpMinChannels != null
+                  ? key.dcpMinChannels
+                  : SpannerOptions.DEFAULT_DYNAMIC_POOL_MIN_CHANNELS;
+          int maxChannels =
+              key.dcpMaxChannels != null
+                  ? key.dcpMaxChannels
+                  : SpannerOptions.DEFAULT_DYNAMIC_POOL_MAX_CHANNELS;
+          int initChannels =
+              key.dcpInitialChannels != null
+                  ? key.dcpInitialChannels
+                  : SpannerOptions.DEFAULT_DYNAMIC_POOL_INITIAL_SIZE;
+          GcpChannelPoolOptions poolOptions =
+              GcpChannelPoolOptions.newBuilder()
+                  .setMinSize(minChannels)
+                  .setMaxSize(maxChannels)
+                  .setInitSize(initChannels)
+                  .setDynamicScaling(
+                      SpannerOptions.DEFAULT_DYNAMIC_POOL_MIN_RPC,
+                      SpannerOptions.DEFAULT_DYNAMIC_POOL_MAX_RPC,
+                      SpannerOptions.DEFAULT_DYNAMIC_POOL_SCALE_DOWN_INTERVAL)
+                  .setAffinityKeyLifetime(SpannerOptions.DEFAULT_DYNAMIC_POOL_AFFINITY_KEY_LIFETIME)
+                  .setCleanupInterval(SpannerOptions.DEFAULT_DYNAMIC_POOL_CLEANUP_INTERVAL)
+                  .build();
+          builder.setGcpChannelPoolOptions(poolOptions);
+        }
+      } else {
+        // Explicitly disable DCP when enableDynamicChannelPool=false.
+        // This ensures consistent behavior even if the default changes in the future.
+        builder.disableDynamicChannelPool();
       }
     }
     if (options.getChannelProvider() != null) {

google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionOptionsTest.java

@@ -1437,7 +1437,10 @@ public void testEnableDynamicChannelPool() {
             .setCredentials(NoCredentials.getInstance())
             .build()
             .isEnableDynamicChannelPool());
-    // Disabled
+  }
+
+  @Test
+  public void testDisableDynamicChannelPool() {
     assertFalse(
         ConnectionOptions.newBuilder()
             .setUri(

google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/SpannerPoolTest.java

@@ -741,4 +741,34 @@ public void testDynamicChannelPoolWithAllSettings() {
                 .setCredentials(NoCredentials.getInstance())
                 .build()));
   }
+
+  @Test
+  public void testExplicitlyDisabledDynamicChannelPool() {
+    SpannerPoolKey keyWithoutDcpSetting =
+        SpannerPoolKey.of(
+            ConnectionOptions.newBuilder()
+                .setUri("cloudspanner:/projects/p/instances/i/databases/d")
+                .setCredentials(NoCredentials.getInstance())
+                .build());
+    SpannerPoolKey keyWithDcpExplicitlyDisabled =
+        SpannerPoolKey.of(
+            ConnectionOptions.newBuilder()
+                .setUri(
+                    "cloudspanner:/projects/p/instances/i/databases/d?enableDynamicChannelPool=false")
+                .setCredentials(NoCredentials.getInstance())
+                .build());
+
+    // Keys should be different because one has explicit false and one has null (default)
+    assertNotEquals(keyWithoutDcpSetting, keyWithDcpExplicitlyDisabled);
+
+    // Verify the explicit false setting is preserved
+    assertEquals(
+        keyWithDcpExplicitlyDisabled,
+        SpannerPoolKey.of(
+            ConnectionOptions.newBuilder()
+                .setUri(
+                    "cloudspanner:/projects/p/instances/i/databases/d?enableDynamicChannelPool=false")
+                .setCredentials(NoCredentials.getInstance())
+                .build()));
+  }
 }