Fix callTracer missing revertReason and nested calls for reverted transactions

CHANGELOG.md

@@ -26,6 +26,7 @@
 
 ### Bug fixes
 - Fix promotion to prioritized layer for gas price fee markets [#9635](https://github.com/hyperledger/besu/pull/9635)
+- Fix callTracer to properly capture nested calls and populate revertReason field when transactions revert [#9651](https://github.com/hyperledger/besu/pull/9651)
 
 ##  25.12.0
 

ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/CallTracerResult.java

@@ -417,7 +417,7 @@ public Builder error(final String error) {
     /**
      * Sets the revert reason if the call was reverted.
      *
-     * @param revertReason the revert reason
+     * @param revertReason the revert reason as raw bytes (will be decoded)
      * @return this builder instance for method chaining
      */
     public Builder revertReason(final Bytes revertReason) {
@@ -426,6 +426,21 @@ public Builder revertReason(final Bytes revertReason) {
       return this;
     }
 
+    /**
+     * Sets the revert reason directly from a decoded string.
+     *
+     * <p>This method should be used when you have already decoded the revert reason and want to set
+     * it directly without any fallback to hex encoding. This is useful for Geth compatibility where
+     * revertReason should only be set if it's a valid decoded Error(string).
+     *
+     * @param revertReason the decoded revert reason string
+     * @return this builder instance for method chaining
+     */
+    public Builder revertReasonDecoded(final String revertReason) {
+      this.revertReason = revertReason;
+      return this;
+    }
+
     /**
      * Sets the list of nested calls made during this call's execution.
      *

ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/CallTracerResultConverter.java

@@ -90,7 +90,10 @@ public static CallTracerResult convert(final TransactionTrace transactionTrace)
   private static CallTracerResult buildCallHierarchyFromFrames(final TransactionTrace trace) {
     final CallTracerResult.Builder rootBuilder = initializeRootBuilder(trace);
 
-    if (!trace.getResult().isSuccessful()) {
+    // Only process frames if transaction succeeded OR reverted (not exceptional halt)
+    // Exceptional halts (stack underflow, out of gas, etc.) happen before execution really begins
+    if (!trace.getResult().isSuccessful()
+        && trace.getResult().getExceptionalHaltReason().isPresent()) {
       return rootBuilder.build();
     }
 

ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/calltrace/CallTracerErrorHandler.java

@@ -16,6 +16,7 @@
 
 import static org.hyperledger.besu.ethereum.api.jsonrpc.internal.results.calltrace.OpcodeCategory.isCreateOp;
 
+import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.JsonRpcErrorResponse;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.results.CallTracerResult;
 import org.hyperledger.besu.ethereum.core.Transaction;
 import org.hyperledger.besu.ethereum.processing.TransactionProcessingResult;
@@ -170,6 +171,9 @@ public static void handleRootError(
         && result.getRevertReason().isPresent()) {
       // For regular calls that reverted, set the output to the revert reason
       builder.output(result.getRevertReason().get().toHexString());
+      // Decode and set revertReason only if it's a valid Error(string) for Geth compatibility
+      JsonRpcErrorResponse.decodeRevertReason(result.getRevertReason().get())
+          .ifPresent(builder::revertReasonDecoded);
     }
   }
 
@@ -193,7 +197,18 @@ public static void setOutputAndErrorStatus(
       handleExceptionalHalt(builder, frame);
     } else if (OpcodeCategory.isRevertOp(opcode)) {
       builder.error(EXECUTION_REVERTED);
-      frame.getRevertReason().ifPresent(builder::revertReason);
+
+      // Try to decode revert reason from output data for Geth compatibility
+      // First check if frame has revert reason set
+      if (frame.getRevertReason().isPresent()) {
+        JsonRpcErrorResponse.decodeRevertReason(frame.getRevertReason().get())
+            .ifPresent(builder::revertReasonDecoded);
+      }
+      // Otherwise, decode from output data if present
+      else if (frame.getOutputData() != null && !frame.getOutputData().isEmpty()) {
+        JsonRpcErrorResponse.decodeRevertReason(frame.getOutputData())
+            .ifPresent(builder::revertReasonDecoded);
+      }
     }
   }