From 77950fe3011e3939e8e3457a5855d44bfacce4d1 Mon Sep 17 00:00:00 2001
From: TangoEnSkai <21152231+TangoEnSkai@users.noreply.github.com>
Date: Sat, 22 Aug 2026 12:05:30 +0900
Subject: [PATCH] fix: return underlying error in EnsureMigrationTable instead
 of swallowing it

EnsureMigrationTable treated any read error as "table does not exist"
and unconditionally attempted to create the migration table. This
masked real failures such as permission errors or deadlines, since
the CREATE TABLE call would then fail with a confusing or misleading
error instead of the original one.

Now only a NotFound error is treated as "table does not exist"; any
other error is returned wrapped in the existing Error type.

Fixes #114
---
 pkg/spanner/client.go | 7 +++++++
 pkg/spanner/errors.go | 1 +
 2 files changed, 8 insertions(+)

diff --git a/pkg/spanner/client.go b/pkg/spanner/client.go
index 68e9898..9997246 100644
--- a/pkg/spanner/client.go
+++ b/pkg/spanner/client.go
@@ -33,6 +33,7 @@ import (
 	"github.com/hashicorp/go-multierror"
 	"google.golang.org/api/iterator"
 	"google.golang.org/api/option"
+	"google.golang.org/grpc/codes"
 )
 
 const (
@@ -491,6 +492,12 @@ func (c *Client) EnsureMigrationTable(ctx context.Context, tableName string) err
 	if err == nil {
 		return nil
 	}
+	if spanner.ErrCode(err) != codes.NotFound {
+		return &Error{
+			Code: ErrorCodeEnsureMigrationTable,
+			err:  err,
+		}
+	}
 
 	stmt := fmt.Sprintf("CREATE TABLE `%s` ("+`
     Version INT64 NOT NULL,
diff --git a/pkg/spanner/errors.go b/pkg/spanner/errors.go
index 3e04121..222e8b7 100644
--- a/pkg/spanner/errors.go
+++ b/pkg/spanner/errors.go
@@ -41,6 +41,7 @@ const (
 	ErrorCodeWaitOperation
 	ErrorCodeCreateInstance
 	ErrorCodeDeleteInstance
+	ErrorCodeEnsureMigrationTable
 )
 
 type Error struct {