db was overwriting on overlapping CIDRs fffaaaaaaaaaaaacccccccckkkkkk my liffffffeeeeeeee

mmdb_writer/mmdb_writer.go

@@ -8,6 +8,7 @@ import (
 	"os"
 
 	"github.com/maxmind/mmdbwriter"
+	"github.com/maxmind/mmdbwriter/inserter"
 	"github.com/maxmind/mmdbwriter/mmdbtype"
 )
 
@@ -27,6 +28,9 @@ func run() error {
 	//   "1.1.1.1": {
 	//     "is_proxy": true,
 	//     "score": 42
+	//   },
+	//   "1.0.0.0/8": {
+	//     "is_hosting": true
 	//   }
 	// }
 	var input map[string]any
@@ -62,6 +66,20 @@ func run() error {
 	}
 
 	// Insert every IP/CIDR.
+	//
+	// Use TopLevelMergeWith instead of the normal Insert method.
+	//
+	// This is important when ranges overlap. For example:
+	//
+	//   1.2.0.0/16 -> {"is_proxy": true}
+	//   1.2.3.0/24 -> {"is_hosting": true}
+	//
+	// An address inside 1.2.3.0/24 will retain both fields:
+	//
+	//   {
+	//     "is_proxy": true,
+	//     "is_hosting": true
+	//   }
 	for address, rawRecord := range input {
 		network, err := parseNetwork(address)
 		if err != nil {
@@ -73,7 +91,10 @@ func run() error {
 			return fmt.Errorf("invalid record for %q: %w", address, err)
 		}
 
-		if err := tree.Insert(network, record); err != nil {
+		if err := tree.InsertFunc(
+			network,
+			inserter.TopLevelMergeWith(record),
+		); err != nil {
 			return fmt.Errorf("inserting %q: %w", address, err)
 		}
 	}