fix: harden scan edge cases

common/parsers/host_iterator_test.go

@@ -2,7 +2,9 @@ package parsers
 
 import (
 	"context"
+	"os"
 	"reflect"
+	"strings"
 	"testing"
 )
 
@@ -59,3 +61,45 @@ func TestHostIteratorExcludeCIDR(t *testing.T) {
 		t.Fatalf("batch = %#v, want %#v", batch, want)
 	}
 }
+
+func TestHostIteratorAcceptsMultipleExcludeSources(t *testing.T) {
+	iter, err := NewHostIterator("192.168.1.0/29", "", "192.168.1.2", "192.168.1.5")
+	if err != nil {
+		t.Fatalf("NewHostIterator error = %v", err)
+	}
+	defer iter.Close()
+
+	batch, err := iter.NextBatch(context.Background(), 10)
+	if err != nil {
+		t.Fatalf("NextBatch error = %v", err)
+	}
+
+	want := []string{"192.168.1.1", "192.168.1.3", "192.168.1.4", "192.168.1.6"}
+	if !reflect.DeepEqual(batch, want) {
+		t.Fatalf("batch = %#v, want %#v", batch, want)
+	}
+}
+
+func TestHostIteratorReadsLongHostFileLine(t *testing.T) {
+	dir := t.TempDir()
+	path := dir + "/hosts.txt"
+	longPrefix := strings.Repeat("a", 70*1024)
+	host := longPrefix + ".example.com"
+	if err := os.WriteFile(path, []byte(host+"\n"), 0o600); err != nil {
+		t.Fatalf("WriteFile error = %v", err)
+	}
+
+	iter, err := NewHostIterator("", path)
+	if err != nil {
+		t.Fatalf("NewHostIterator error = %v", err)
+	}
+	defer iter.Close()
+
+	batch, err := iter.NextBatch(context.Background(), 1)
+	if err != nil {
+		t.Fatalf("NextBatch error = %v", err)
+	}
+	if !reflect.DeepEqual(batch, []string{host}) {
+		t.Fatalf("batch = %#v, want long host", batch)
+	}
+}