codegen: don't skip created_at auto-timestamp for 'without rowid' tables

pkg/codegen/modelgenerate/generate_model.go

@@ -386,6 +386,24 @@ func GenerateSaveItemFunc(tbl schema.Table) *ast.FuncDecl {
 			}
 
 			if tbl.IsWithoutRowid {
+				if hasCreatedAt {
+					// Auto-timestamps: created_at.  Don't overwrite existing timestamps (e.g., data import / migrations)
+					ret = append(ret, &ast.IfStmt{
+						Cond: &ast.CallExpr{Fun: &ast.SelectorExpr{
+							X:   &ast.SelectorExpr{X: ast.NewIdent(tbl.VarName), Sel: ast.NewIdent("CreatedAt")},
+							Sel: ast.NewIdent("IsZero"),
+						}},
+						Body: &ast.BlockStmt{
+							List: []ast.Stmt{
+								&ast.AssignStmt{
+									Lhs: []ast.Expr{&ast.SelectorExpr{X: ast.NewIdent(tbl.VarName), Sel: ast.NewIdent("CreatedAt")}},
+									Tok: token.ASSIGN,
+									Rhs: []ast.Expr{&ast.CallExpr{Fun: ast.NewIdent("TimestampNow"), Args: []ast.Expr{}}},
+								},
+							},
+						},
+					})
+				}
 				ret = append(ret, namedExecStmt(upsertStmt)...)
 				ret = append(ret, PanicIfRowsAffected(tbl))
 			} else {