feat: add StrictFieldMapping config

qrm/qrm.go

@@ -6,8 +6,9 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/go-jet/jet/v2/internal/utils/must"
 	"reflect"
+
+	"github.com/go-jet/jet/v2/internal/utils/must"
 )
 
 // Config holds the configuration settings for QRM scanning behavior.
@@ -18,6 +19,13 @@ type Config struct {
 	// Does not apply to statements build with SELECT_JSON_OBJ or SELECT_JSON_ARR
 	StrictScan bool
 
+	// StrictFieldMapping, when true, causes the scanning function to panic if it encounters any
+	// destination struct fields that do not have matching columns in the SQL query result.
+	// This check applies only to fields that are mapped from a single column (simple/scanner/json_column).
+	// Complex fields (struct/slice) are excluded because they are populated recursively and can be optional.
+	// Does not apply to statements build with SELECT_JSON_OBJ or SELECT_JSON_ARR
+	StrictFieldMapping bool
+
 	// JsonUnmarshalFunc is called by the Query method to unmarshal JSON query results created by
 	// SELECT_JSON_OBJ and SELECT_JSON_ARR statements.
 	// It can be replaced with any implementation that matches the standard "encoding/json" `Unmarshal` function signature.
@@ -28,8 +36,9 @@ type Config struct {
 // GlobalConfig is the package-wide configuration for SQL scanning.
 // This variable is not thread safe, and it should be modified only once, for instance, during application initialization.
 var GlobalConfig = Config{
-	StrictScan:        false,
-	JsonUnmarshalFunc: json.Unmarshal,
+	StrictScan:         false,
+	StrictFieldMapping: false,
+	JsonUnmarshalFunc:  json.Unmarshal,
 }
 
 // ErrNoRows is returned by Query when query result set is empty
@@ -230,6 +239,9 @@ func ScanOneRowToDest(scanContext *ScanContext, rows *sql.Rows, destPtr interfac
 	}
 
 	scanContext.EnsureEveryColumnRead() // can panic
+	if GlobalConfig.StrictFieldMapping {
+		scanContext.EnsureEveryFieldMapped() // can panic
+	}
 
 	return nil
 }
@@ -276,6 +288,9 @@ func queryToSlice(ctx context.Context, db Queryable, query string, args []interf
 		if scanContext.rowNum == 1 && GlobalConfig.StrictScan {
 			scanContext.EnsureEveryColumnRead()
 		}
+		if scanContext.rowNum == 1 && GlobalConfig.StrictFieldMapping {
+			scanContext.EnsureEveryFieldMapped()
+		}
 	}
 
 	err = rows.Close()