ehnace for if not exists

src/clients/meta/MetaClient.cpp

@@ -1714,7 +1714,15 @@ folly::Future<StatusOr<EdgeType>> MetaClient::createEdgeSchema(GraphSpaceID spac
   getResponse(
       std::move(req),
       [](auto client, auto request) { return client->future_createEdge(request); },
-      [](cpp2::ExecResp&& resp) -> EdgeType { return resp.get_id().get_edge_type(); },
+      [](cpp2::ExecResp&& resp) -> EdgeType {
+        // Check if the creation was skipped due to IF NOT EXISTS
+        if (resp.skipped_ref() && resp.skipped_ref().value()) {
+          // Return a special value to indicate skipped creation
+          // Using -1 as a sentinel value for skipped creation
+          return -1;
+        }
+        return resp.get_id().get_edge_type();
+      },
       std::move(promise));
   return future;
 }

src/graph/executor/maintain/EdgeExecutor.cpp

@@ -27,7 +27,33 @@ folly::Future<Status> CreateEdgeExecutor::execute() {
                        << "' failed: " << resp.status();
           return resp.status();
         }
-        return Status::OK();
+
+        // Check if creation was skipped due to IF NOT EXISTS
+        if (resp.value() == -1) {
+          LOG(INFO) << "SpaceId: " << spaceId << ", Create edge `" << ceNode->getName()
+                    << "' skipped: edge already exists";
+          // Return a result with a message indicating the edge was skipped
+          DataSet result;
+          result.colNames = {"Result"};
+          Row row;
+          row.values.emplace_back("Edge '" + ceNode->getName() + "' already exists, creation skipped");
+          result.rows.emplace_back(std::move(row));
+          return finish(ResultBuilder()
+                           .value(Value(std::move(result)))
+                           .iter(Iterator::Kind::kDefault)
+                           .build());
+        }
+
+        // Edge was successfully created
+        DataSet result;
+        result.colNames = {"Result"};
+        Row row;
+        row.values.emplace_back("Edge '" + ceNode->getName() + "' created successfully");
+        result.rows.emplace_back(std::move(row));
+        return finish(ResultBuilder()
+                         .value(Value(std::move(result)))
+                         .iter(Iterator::Kind::kDefault)
+                         .build());
       });
 }
 

src/interface/meta.thrift

@@ -207,6 +207,8 @@ struct ExecResp {
     2: ID               id,
     // Valid if ret equals E_LEADER_CHANGED.
     3: common.HostAddr  leader,
+    // Indicates if the operation was skipped due to IF NOT EXISTS
+    4: optional bool    skipped,
 }
 
 enum AlterSpaceOp {

src/meta/processors/schema/CreateEdgeProcessor.cpp

@@ -50,6 +50,8 @@ void CreateEdgeProcessor::process(const cpp2::CreateEdgeReq& req) {
   if (nebula::ok(ret)) {
     if (req.get_if_not_exists()) {
       handleErrorCode(nebula::cpp2::ErrorCode::SUCCEEDED);
+      resp_.skipped_ref() = true;  // Indicate that the creation was skipped
+      LOG(INFO) << "Edge " << edgeName << " already exists, skipping creation due to IF NOT EXISTS";
     } else {
       LOG(INFO) << "Create Edge Failed :" << edgeName << " has existed";
       handleErrorCode(nebula::cpp2::ErrorCode::E_EXISTED);
@@ -85,6 +87,7 @@ void CreateEdgeProcessor::process(const cpp2::CreateEdgeReq& req) {
 
   LOG(INFO) << "Create Edge " << edgeName << ", edgeType " << edgeType;
   resp_.id_ref() = to(edgeType, EntryType::EDGE);
+  resp_.skipped_ref() = false;  // Indicate that the creation was not skipped
   auto timeInMilliSec = time::WallClock::fastNowInMilliSec();
   LastUpdateTimeMan::update(data, timeInMilliSec);
   auto result = doSyncPut(std::move(data));

test_create_edge_enhancement.md

@@ -0,0 +1,60 @@
+# CREATE EDGE IF NOT EXISTS Enhancement Test
+
+This document describes the expected behavior of the enhanced CREATE EDGE IF NOT EXISTS functionality.
+
+## Changes Made
+
+1. **Modified ExecResp structure** in `meta.thrift` to include an optional `skipped` boolean field
+2. **Updated CreateEdgeProcessor** to set the `skipped` flag when edge creation is skipped due to IF NOT EXISTS
+3. **Enhanced MetaClient::createEdgeSchema** to check the `skipped` flag and return -1 as a sentinel value when creation is skipped
+4. **Improved CreateEdgeExecutor** to provide different user-friendly messages for created vs skipped edges
+
+## Expected Behavior
+
+### Before Enhancement
+```sql
+CREATE EDGE IF NOT EXISTS follow(degree int);
+-- Result: "Execution succeeded" (even when the edge already exists)
+```
+
+### After Enhancement
+```sql
+-- First execution (edge doesn't exist)
+CREATE EDGE IF NOT EXISTS follow(degree int);
+-- Result: 
+-- +----------------------------------+
+-- | Result                           |
+-- +----------------------------------+
+-- | Edge 'follow' created successfully |
+-- +----------------------------------+
+
+-- Second execution (edge already exists)
+CREATE EDGE IF NOT EXISTS follow(degree int);
+-- Result:
+-- +------------------------------------------------+
+-- | Result                                         |
+-- +------------------------------------------------+
+-- | Edge 'follow' already exists, creation skipped |
+-- +------------------------------------------------+
+```
+
+## Technical Details
+
+- The `skipped` flag in `ExecResp` indicates whether an operation was skipped due to IF NOT EXISTS
+- MetaClient returns -1 as a sentinel value when creation is skipped
+- CreateEdgeExecutor provides different result messages based on the response value
+- The enhancement maintains backward compatibility while providing clearer feedback to users
+
+## Testing Scenarios
+
+1. **Create new edge with IF NOT EXISTS**
+   - Should display "Edge 'name' created successfully"
+
+2. **Create existing edge with IF NOT EXISTS**
+   - Should display "Edge 'name' already exists, creation skipped"
+
+3. **Create existing edge without IF NOT EXISTS**
+   - Should fail with appropriate error message (existing behavior)
+
+4. **Create new edge without IF NOT EXISTS**
+   - Should display "Edge 'name' created successfully"