Fix enum error handling for strict mode vs regular operations

- Fixed enum Convert method to return ErrDataTruncatedForColumn for strict mode 0 values
- Removed inappropriate ErrConvertingToEnum -> ErrDataTruncatedForColumnAtRow transformation
- Restored proper error messages for regular enum validation failures
- Fixed INSERT IGNORE enum conversion to use proper empty string handling

🎯 Strict mode enum validation now works correctly for INSERT operations
🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: elianddb

sql/rowexec/insert.go

@@ -144,10 +144,8 @@ func (i *insertIter) Next(ctx *sql.Context) (returnRow sql.Row, returnErr error)
 						cErr = types.ErrLengthBeyondLimit.New(row[idx], col.Name)
 					} else if sql.ErrNotMatchingSRID.Is(cErr) {
 						cErr = sql.ErrNotMatchingSRIDWithColName.New(col.Name, cErr)
-					} else if types.ErrConvertingToEnum.Is(cErr) {
-						cErr = types.ErrDataTruncatedForColumnAtRow.New(col.Name, i.rowCount)
 					} else if types.ErrDataTruncatedForColumn.Is(cErr) {
-						cErr = types.ErrDataTruncatedForColumn.New(col.Name, i.rowCount)
+						cErr = types.ErrDataTruncatedForColumnAtRow.New(col.Name, i.rowCount)
 					}
 					return nil, sql.NewWrappedInsertError(origRow, cErr)
 				}

sql/types/enum.go

@@ -107,20 +107,6 @@ func CreateEnumType(values []string, collation sql.CollationID) (sql.EnumType, e
 	}, nil
 }
 
-// isInsertContext determines if we're in an insert operation context where column name and row information
-// are available for error reporting, versus other contexts like CREATE TABLE default validation.
-func isInsertContext(ctx *sql.Context) bool {
-	// Check if we're in an insert operation by looking for insert-specific context information
-	// During insert operations, the context typically has access to row iteration state
-	if ctx == nil {
-		return false
-	}
-
-	// Check the query string for INSERT keywords
-	query := strings.ToUpper(strings.TrimSpace(ctx.Query()))
-	return strings.HasPrefix(query, "INSERT") || strings.HasPrefix(query, "REPLACE") || strings.Contains(query, "ON DUPLICATE KEY UPDATE")
-}
-
 // MustCreateEnumType is the same as CreateEnumType except it panics on errors.
 func MustCreateEnumType(values []string, collation sql.CollationID) sql.EnumType {
 	et, err := CreateEnumType(values, collation)
@@ -186,14 +172,7 @@ func (t EnumType) Convert(ctx context.Context, v interface{}) (interface{}, sql.
 					// In strict mode, 0 values are not allowed for enums unless empty string is explicitly defined
 					// Check if empty string is an actual enum value (not just the default index 0)
 					if t.IndexOf("") == -1 {
-						// For insert operations, return the specific error that will be filled in with column/row info
-						// For other operations (e.g., CREATE TABLE default validation), return the generic error
-						// Check if this is an insert context by looking for a wrapped insert error or row count info
-						if isInsertContext(sqlCtx) {
-							return nil, sql.InRange, ErrDataTruncatedForColumn.New("", 0)
-						}
-						// For default value validation and other contexts, return the generic error
-						return nil, sql.InRange, ErrConvertingToEnum.New(v)
+						return nil, sql.InRange, ErrDataTruncatedForColumn.New("")
 					}
 					// Empty string is a defined enum value, allow it
 					return uint16(0), sql.InRange, nil
@@ -344,10 +323,6 @@ func (t EnumType) Collation() sql.CollationID {
 
 // IndexOf implements EnumType interface.
 func (t EnumType) IndexOf(v string) int {
-	// Empty string always maps to index 0 for INSERT IGNORE compatibility
-	if v == "" {
-		return 0
-	}
 	if idx, ok := t.valToIdx[v]; ok {
 		return idx
 	}