refactor(config): merge config files with BeanDefaults fallback

common/src/main/java/org/tron/core/config/BeanDefaults.java

@@ -0,0 +1,93 @@
+package org.tron.core.config;
+
+import com.typesafe.config.Config;
+import com.typesafe.config.ConfigFactory;
+import java.beans.BeanInfo;
+import java.beans.Introspector;
+import java.beans.PropertyDescriptor;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Generates a Typesafe {@link Config} from a bean instance's current field values.
+ *
+ * <p>Used by each {@code XxxConfig.fromConfig()} to replace the role that
+ * {@code reference.conf} played: ensures every key ConfigBeanFactory needs is
+ * present, so a partial user config works without throwing
+ * {@code ConfigException.Missing}.
+ *
+ * <p>Only public getter+setter pairs (standard JavaBean properties) are included —
+ * the same set that {@code ConfigBeanFactory.create()} auto-binds. Keys are
+ * decapitalized exactly as ConfigBeanFactory does:
+ * {@code Character.toLowerCase(name.charAt(0)) + name.substring(1)}.
+ *
+ * <p>Nested bean fields are recursed into nested HOCON objects.
+ * {@code List} fields are serialized as HOCON lists (empty by default).
+ * Fields with no public setter (e.g. {@code @Getter(AccessLevel.NONE)} overrides)
+ * are automatically skipped — these are handled manually in each
+ * {@code fromConfig()} via {@code hasPath} guards.
+ */
+public final class BeanDefaults {
+
+  private BeanDefaults() {}
+
+  /**
+   * Convert {@code bean}'s public JavaBean properties to a Typesafe Config.
+   * The resulting Config can be used as a {@code withFallback()} for a user's
+   * config section to guarantee all keys are present for ConfigBeanFactory.
+   */
+  public static Config toConfig(Object bean) {
+    return ConfigFactory.parseMap(toMap(bean));
+  }
+
+  private static Map<String, Object> toMap(Object bean) {
+    Map<String, Object> map = new LinkedHashMap<>();
+    try {
+      BeanInfo info = Introspector.getBeanInfo(bean.getClass());
+      for (PropertyDescriptor pd : info.getPropertyDescriptors()) {
+        Method getter = pd.getReadMethod();
+        Method setter = pd.getWriteMethod();
+        // Skip read-only properties (no setter) — matches ConfigBeanFactory's contract
+        if (getter == null || setter == null) {
+          continue;
+        }
+        // Use the property name exactly as Introspector produced it.
+        // ConfigBeanFactory does configProps.get(beanProp.getName()) — the lookup key
+        // is the property name verbatim, not decapitalized.  For ordinary camelCase
+        // setters (setMaxConnections → "MaxConnections" → decapitalize → "maxConnections")
+        // Introspector already returns the lowercase form.  For setters that start with
+        // two consecutive uppercase letters (setPBFTEnable → "PBFTEnable") the JavaBean
+        // spec forbids decapitalization, so pd.getName() == "PBFTEnable" — matching the
+        // capital-P key that config.conf uses for those fields.
+        String key = pd.getName();
+        Object value = getter.invoke(bean);
+        map.put(key, toValue(value));
+      }
+    } catch (Exception ignored) {
+      // Best-effort: any unresolvable field is simply omitted.
+      // ConfigBeanFactory will throw with a clear path if a required key is missing.
+    }
+    return map;
+  }
+
+  private static Object toValue(Object value) {
+    if (value == null) {
+      return "";
+    }
+    if (value instanceof Boolean || value instanceof Number || value instanceof String) {
+      return value;
+    }
+    if (value instanceof List) {
+      List<Object> list = new ArrayList<>();
+      for (Object item : (List<?>) value) {
+        list.add(toValue(item));
+      }
+      return list;
+    }
+    // Assume nested bean — recurse so it becomes a nested HOCON object.
+    return toMap(value);
+  }
+}

common/src/main/java/org/tron/core/config/Configuration.java

@@ -48,10 +48,11 @@ public static com.typesafe.config.Config getByFileName(
 
   private static void resolveConfigFile(String fileName, File confFile) {
     if (confFile.exists()) {
-      config = ConfigFactory.parseFile(confFile)
-          .withFallback(ConfigFactory.defaultReference());
+      config = ConfigFactory.parseFile(confFile);
     } else if (Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName)
         != null) {
+      // ConfigFactory.load merges system properties (higher priority than the file),
+      // which tests rely on to override storage.db.engine via -D flags.
       config = ConfigFactory.load(fileName);
     } else {
       throw new IllegalArgumentException(

common/src/main/java/org/tron/core/config/args/BlockConfig.java

@@ -7,6 +7,7 @@
 
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigBeanFactory;
+import org.tron.core.config.BeanDefaults;
 import lombok.Getter;
 import lombok.Setter;
 import lombok.extern.slf4j.Slf4j;
@@ -25,8 +26,6 @@ public class BlockConfig {
   private long proposalExpireTime = DEFAULT_PROPOSAL_EXPIRE_TIME;
   private int checkFrozenTime = 1;
 
-  // Defaults come from reference.conf (loaded globally via Configuration.java)
-
   /**
    * Create BlockConfig from the "block" section of the application config.
    * Also checks that committee.proposalExpireTime is not used (must use block.proposalExpireTime).
@@ -38,7 +37,10 @@ public static BlockConfig fromConfig(Config config) {
           + "config.conf, please set the value in block.proposalExpireTime.", PARAMETER_INIT);
     }
 
-    Config blockSection = config.getConfig("block");
+    Config defaults = BeanDefaults.toConfig(new BlockConfig());
+    Config blockSection = config.hasPath("block")
+        ? config.getConfig("block").withFallback(defaults)
+        : defaults;
     BlockConfig blockConfig = ConfigBeanFactory.create(blockSection, BlockConfig.class);
     blockConfig.postProcess();
     return blockConfig;

common/src/main/java/org/tron/core/config/args/CommitteeConfig.java

@@ -2,6 +2,7 @@
 
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigBeanFactory;
+import org.tron.core.config.BeanDefaults;
 import lombok.Getter;
 import lombok.Setter;
 import lombok.extern.slf4j.Slf4j;
@@ -87,8 +88,6 @@ public class CommitteeConfig {
 
   // proposalExpireTime is NOT a committee field — it's in block.* and handled by BlockConfig
 
-  // Defaults come from reference.conf (loaded globally via Configuration.java)
-
   /**
    * Create CommitteeConfig from the "committee" section of the application config.
    *
@@ -100,8 +99,10 @@ public class CommitteeConfig {
   private static final String ALLOW_PBFT_KEY = "allowPBFT";
 
   public static CommitteeConfig fromConfig(Config config) {
-    Config section = config.getConfig("committee");
-
+    Config defaults = BeanDefaults.toConfig(new CommitteeConfig());
+    Config section = config.hasPath("committee")
+        ? config.getConfig("committee").withFallback(defaults)
+        : defaults;
     CommitteeConfig cc = ConfigBeanFactory.create(section, CommitteeConfig.class);
     // Ensure the manually-named fields get the right values from the original keys
     cc.allowPBFT = section.hasPath(ALLOW_PBFT_KEY) ? section.getLong(ALLOW_PBFT_KEY) : 0;

common/src/main/java/org/tron/core/config/args/EventConfig.java

@@ -3,6 +3,7 @@
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigBeanFactory;
 import com.typesafe.config.ConfigFactory;
+import org.tron.core.config.BeanDefaults;
 import java.util.ArrayList;
 import java.util.List;
 import lombok.Getter;
@@ -68,23 +69,27 @@ public static class FilterConfig {
     private List<String> contractTopic = new ArrayList<>();
   }
 
-  // Defaults come from reference.conf (loaded globally via Configuration.java)
-
   /**
    * Create EventConfig from the "event.subscribe" section of the application config.
    *
    * <p>Note: HOCON key "native" is a Java reserved word, so the bean field is named
    * "nativeQueue" but config key is "native". We handle this manually after binding.
    */
   public static EventConfig fromConfig(Config config) {
-    Config section = config.getConfig("event.subscribe");
+    // BeanDefaults covers enable/version/startSyncBlockNum/path/server/dbconfig/
+    // contractParse/filter. nativeQueue and topics are excluded (no public setter).
+    Config defaults = BeanDefaults.toConfig(new EventConfig());
+    Config section = config.hasPath("event.subscribe")
+        ? config.getConfig("event.subscribe")
+        : ConfigFactory.empty();
 
     // "native" is a Java reserved word, "topics" has optional fields per item —
     // strip both before binding, read manually
     String nativeKey = "native";
     String topicsKey = "topics";
     Config bindable = section.withoutPath(nativeKey).withoutPath(topicsKey)
-        .withoutPath("topicDefaults");
+        .withoutPath("topicDefaults")
+        .withFallback(defaults);
     EventConfig ec = ConfigBeanFactory.create(bindable, EventConfig.class);
 
     // manually bind "native" sub-section

common/src/main/java/org/tron/core/config/args/GenesisConfig.java

@@ -2,6 +2,7 @@
 
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigBeanFactory;
+import org.tron.core.config.BeanDefaults;
 import java.util.ArrayList;
 import java.util.List;
 import lombok.Getter;
@@ -41,10 +42,11 @@ public static class WitnessConfig {
     private long voteCount = 0;
   }
 
-  // Defaults come from reference.conf (loaded globally via Configuration.java)
-
   public static GenesisConfig fromConfig(Config config) {
-    Config section = config.getConfig("genesis.block");
+    Config defaults = BeanDefaults.toConfig(new GenesisConfig());
+    Config section = config.hasPath("genesis.block")
+        ? config.getConfig("genesis.block").withFallback(defaults)
+        : defaults;
     return ConfigBeanFactory.create(section, GenesisConfig.class);
   }
 }

common/src/main/java/org/tron/core/config/args/MetricsConfig.java

@@ -2,6 +2,7 @@
 
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigBeanFactory;
+import org.tron.core.config.BeanDefaults;
 import lombok.Getter;
 import lombok.Setter;
 import lombok.extern.slf4j.Slf4j;
@@ -35,13 +36,11 @@ public static class InfluxDbConfig {
     private int metricsReportInterval = 10;
   }
 
-  // Defaults come from reference.conf (loaded globally via Configuration.java)
-
-  /**
-   * Create MetricsConfig from the "node.metrics" section of the application config.
-   */
   public static MetricsConfig fromConfig(Config config) {
-    Config section = config.getConfig("node.metrics");
+    Config defaults = BeanDefaults.toConfig(new MetricsConfig());
+    Config section = config.hasPath("node.metrics")
+        ? config.getConfig("node.metrics").withFallback(defaults)
+        : defaults;
     return ConfigBeanFactory.create(section, MetricsConfig.class);
   }
 }

common/src/main/java/org/tron/core/config/args/NodeConfig.java

@@ -5,6 +5,7 @@
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigBeanFactory;
 import com.typesafe.config.ConfigFactory;
+import org.tron.core.config.BeanDefaults;
 import java.util.ArrayList;
 import java.util.List;
 import lombok.Getter;
@@ -89,8 +90,8 @@ public class NodeConfig {
   private double activeConnectFactor = 0.1;
   private double connectFactor = 0.6;
   // Legacy alias `maxActiveNodesWithSameIp` has no bean field: we only peek at it via
-  // section.hasPath() below. Keeping it field-less means reference.conf doesn't have to
-  // ship a default that would otherwise mask the modern `maxConnectionsWithSameIp` key.
+  // section.hasPath() below. Keeping it field-less means BeanDefaults does not emit a
+  // default that would mask the modern `maxConnectionsWithSameIp` key.
 
   // ---- Sub-beans matching config's dot-notation nested structure ----
   private ListenConfig listen = new ListenConfig();
@@ -339,8 +340,6 @@ public static class DnsConfig {
     private String awsHostZoneId = "";
   }
 
-  // Defaults come from reference.conf (loaded globally via Configuration.java)
-
   // ===========================================================================
   // Factory method
   // ===========================================================================
@@ -359,8 +358,10 @@ public static class DnsConfig {
    * since ConfigBeanFactory expects typed bean lists, not string lists.
    */
   public static NodeConfig fromConfig(Config config) {
-    Config section = config.getConfig("node");
-
+    Config defaults = BeanDefaults.toConfig(new NodeConfig());
+    Config section = config.hasPath("node")
+        ? config.getConfig("node").withFallback(defaults)
+        : defaults;
     // Auto-bind all fields and sub-beans. ConfigBeanFactory fails fast with a
     // descriptive path on any `= null` value — external configs that use the
     // HOCON null keyword should fix their config rather than rely on silent coercion.
@@ -386,7 +387,7 @@ public static NodeConfig fromConfig(Config config) {
     }
 
     // Legacy key fallback: node.fullNodeAllowShieldedTransaction -> allowShieldedTransactionApi.
-    // reference.conf does not ship the legacy key, so hasPath here reliably means the user
+    // BeanDefaults does not emit this legacy key, so hasPath here reliably means the user
     // set it in their config. When present, it overrides the modern key.
     if (section.hasPath("fullNodeAllowShieldedTransaction")) {
       nc.allowShieldedTransactionApi = section.getBoolean("fullNodeAllowShieldedTransaction");

common/src/main/java/org/tron/core/config/args/RateLimiterConfig.java

@@ -2,6 +2,7 @@
 
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigBeanFactory;
+import org.tron.core.config.BeanDefaults;
 import java.util.ArrayList;
 import java.util.List;
 import lombok.Getter;
@@ -66,10 +67,11 @@ public static class RpcRateLimitItem {
     private String paramString = "";
   }
 
-  // Defaults come from reference.conf (loaded globally via Configuration.java)
-
   public static RateLimiterConfig fromConfig(Config config) {
-    Config section = config.getConfig("rate.limiter");
+    Config defaults = BeanDefaults.toConfig(new RateLimiterConfig());
+    Config section = config.hasPath("rate.limiter")
+        ? config.getConfig("rate.limiter").withFallback(defaults)
+        : defaults;
     return ConfigBeanFactory.create(section, RateLimiterConfig.class);
   }
 }

common/src/main/java/org/tron/core/config/args/StorageConfig.java

@@ -2,6 +2,7 @@
 
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigBeanFactory;
+import org.tron.core.config.BeanDefaults;
 import com.typesafe.config.ConfigObject;
 import java.util.ArrayList;
 import java.util.List;
@@ -205,11 +206,14 @@ public static class PropertyConfig {
     private int maxOpenFiles = 100;
   }
 
-  // Defaults come from reference.conf (loaded globally via Configuration.java)
-
   public static StorageConfig fromConfig(Config config) {
-    Config section = config.getConfig("storage");
-
+    Config defaults = BeanDefaults.toConfig(new StorageConfig());
+    // User's storage section takes priority; defaults fill in any omitted scalar keys.
+    // readDbOption() uses hasPath() on the merged section, so user-set optional keys
+    // (default, defaultM, defaultL) are still detected correctly.
+    Config section = config.hasPath("storage")
+        ? config.getConfig("storage").withFallback(defaults)
+        : defaults;
     StorageConfig sc = ConfigBeanFactory.create(section, StorageConfig.class);
     sc.rawStorageConfig = section;
 

common/src/main/java/org/tron/core/config/args/VmConfig.java

@@ -2,6 +2,7 @@
 
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigBeanFactory;
+import org.tron.core.config.BeanDefaults;
 import lombok.Getter;
 import lombok.Setter;
 import lombok.extern.slf4j.Slf4j;
@@ -28,13 +29,11 @@ public class VmConfig {
   private boolean saveFeaturedInternalTx = false;
   private boolean saveCancelAllUnfreezeV2Details = false;
 
-  /**
-   * Create VmConfig from the "vm" section of the application config.
-   * Defaults come from reference.conf (loaded globally via Configuration.java),
-   * so no per-bean DEFAULTS needed.
-   */
   public static VmConfig fromConfig(Config config) {
-    Config vmSection = config.getConfig("vm");
+    Config defaults = BeanDefaults.toConfig(new VmConfig());
+    Config vmSection = config.hasPath("vm")
+        ? config.getConfig("vm").withFallback(defaults)
+        : defaults;
     VmConfig vmConfig = ConfigBeanFactory.create(vmSection, VmConfig.class);
     vmConfig.postProcess();
     return vmConfig;