all: use %w instead of %v to wrap errors (#1275)

* all: use %w instead of %v for nested errors with fmt.Errorf

* all: update generated code to use %w instead of %v for error wrapping

entc/gen/template/dialect/sql/decode.tmpl

@@ -98,7 +98,7 @@ func ({{ $receiver }} *{{ $.Name }}) assignValues(columns []string, values []int
 			return fmt.Errorf("unexpected type %T for field {{ $f.Name }}", values[{{ $i }}])
 		} else if value != nil && len(*value) > 0 {
 			if err := json.Unmarshal(*value, &{{ $ret }}.{{ $field }}); err != nil {
-				return fmt.Errorf("unmarshal field {{ $f.Name }}: %v", err)
+				return fmt.Errorf("unmarshal field {{ $f.Name }}: %w", err)
 			}
 		}
 	{{- else }}

entc/gen/template/dialect/sql/errors.tmpl

@@ -30,7 +30,7 @@ func isSQLConstraintError(err error) (*ConstraintError, bool) {
 // rollback calls tx.Rollback and wraps the given error with the rollback error if present.
 func rollback(tx dialect.Tx, err error) error {
 	if rerr := tx.Rollback(); rerr != nil {
-		err = fmt.Errorf("%s: %v", err.Error(), rerr)
+		err = fmt.Errorf("%w: %v", err, rerr)
 	}
 	if err, ok := isSQLConstraintError(err); ok {
 		return err

entc/gen/template/dialect/sql/query.tmpl

@@ -84,7 +84,7 @@ func ({{ $receiver }} *{{ $builder }}) sqlCount(ctx context.Context) (int, error
 func ({{ $receiver }} *{{ $builder }}) sqlExist(ctx context.Context) (bool, error) {
 	n, err := {{ $receiver }}.sqlCount(ctx)
 	if err != nil {
-		return false, fmt.Errorf("{{ $pkg }}: check existence: %v", err)
+		return false, fmt.Errorf("{{ $pkg }}: check existence: %w", err)
 	}
 	return n > 0, nil
 }
@@ -288,7 +288,7 @@ func ({{ $receiver }} *{{ $builder }}) sqlQuery(ctx context.Context) *sql.Select
 				{{- end }}
 			{{- end }}
 			if err := sqlgraph.QueryEdges(ctx, {{ $receiver }}.driver, _spec); err != nil {
-				return nil, fmt.Errorf(`query edges "{{ $e.Name }}": %v`, err)
+				return nil, fmt.Errorf(`query edges "{{ $e.Name }}": %w`, err)
 			}
 			query.Where({{ $e.Type.Package }}.IDIn(edgeids...))
 			neighbors, err := query.All(ctx)

entc/gen/template/dialect/sql/tx.tmpl

@@ -14,7 +14,7 @@ func (c *Client) BeginTx(ctx context.Context, opts *sql.TxOptions) (*Tx, error)
 		BeginTx(context.Context, *sql.TxOptions) (dialect.Tx, error)
 	}).BeginTx(ctx, opts)
 	if err != nil {
-		return nil, fmt.Errorf("ent: starting a transaction: %v", err)
+		return nil, fmt.Errorf("ent: starting a transaction: %w", err)
 	}
 	cfg := c.config
 	cfg.driver = &txDriver{tx: tx, drv: c.driver}