refactor: database interaction and error handling (#10762)

This pull request introduces a significant refactoring of the database
interaction layer, focusing on improving explicitness, transactional
control, and error handling. The core change is the removal of the
stateful `QueryExecutor` from repository instances. Instead, it is now
passed as an argument to each method that interacts with the database.

This change makes transaction management more explicit and flexible, as
the same repository instance can be used with a database pool or a
specific transaction without needing to be re-instantiated.

### Key Changes

- **Explicit `QueryExecutor` Passing:**
- All repository methods (`Get`, `List`, `Create`, `Update`, `Delete`,
etc.) in `InstanceRepository`, `OrganizationRepository`,
`UserRepository`, and their sub-repositories now require a
`database.QueryExecutor` (e.g., a `*pgxpool.Pool` or `pgx.Tx`) as the
first argument.
- Repository constructors no longer accept a `QueryExecutor`. For
example, `repository.InstanceRepository(pool)` is now
`repository.InstanceRepository()`.

- **Enhanced Error Handling:**
- A new `database.MissingConditionError` is introduced to enforce
required query conditions, such as ensuring an `instance_id` is always
present in `UPDATE` and `DELETE` operations.
- The database error wrapper in the `postgres` package now correctly
identifies and wraps `pgx.ErrTooManyRows` and similar errors from the
`scany` library into a `database.MultipleRowsFoundError`.

- **Improved Database Conditions:**
- The `database.Condition` interface now includes a
`ContainsColumn(Column) bool` method. This allows for runtime checks to
ensure that critical filters (like `instance_id`) are included in a
query, preventing accidental cross-tenant data modification.
- A new `database.Exists()` condition has been added to support `EXISTS`
subqueries, enabling more complex filtering logic, such as finding an
organization that has a specific domain.

- **Repository and Interface Refactoring:**
- The method for loading related entities (e.g., domains for an
organization) has been changed from a boolean flag (`Domains(true)`) to
a more explicit, chainable method (`LoadDomains()`). This returns a new
repository instance configured to load the sub-resource, promoting
immutability.
- The custom `OrgIdentifierCondition` has been removed in favor of using
the standard `database.Condition` interface, simplifying the API.

- **Code Cleanup and Test Updates:**
  - Unnecessary struct embeddings and metadata have been removed.
- All integration and repository tests have been updated to reflect the
new method signatures, passing the database pool or transaction object
explicitly.
- New tests have been added to cover the new `ExistsDomain`
functionality and other enhancements.

These changes make the data access layer more robust, predictable, and
easier to work with, especially in the context of database transactions.

backend/v3/storage/database/repository/instance_domain.go

@@ -10,9 +10,18 @@ import (
 
 var _ domain.InstanceDomainRepository = (*instanceDomain)(nil)
 
-type instanceDomain struct {
-	repository
-	*instance
+type instanceDomain struct{}
+
+func InstanceDomainRepository() domain.InstanceDomainRepository {
+	return new(instanceDomain)
+}
+
+func (instanceDomain) qualifiedTableName() string {
+	return "zitadel.instance_domains"
+}
+
+func (instanceDomain) unqualifiedTableName() string {
+	return "instance_domains"
 }
 
 // -------------------------------------------------------------
@@ -23,8 +32,7 @@ const queryInstanceDomainStmt = `SELECT instance_domains.instance_id, instance_d
 	`FROM zitadel.instance_domains`
 
 // Get implements [domain.InstanceDomainRepository].
-// Subtle: this method shadows the method ([domain.InstanceRepository]).Get of instanceDomain.instance.
-func (i *instanceDomain) Get(ctx context.Context, opts ...database.QueryOption) (*domain.InstanceDomain, error) {
+func (i instanceDomain) Get(ctx context.Context, client database.QueryExecutor, opts ...database.QueryOption) (*domain.InstanceDomain, error) {
 	options := new(database.QueryOpts)
 	for _, opt := range opts {
 		opt(options)
@@ -34,12 +42,11 @@ func (i *instanceDomain) Get(ctx context.Context, opts ...database.QueryOption)
 	builder.WriteString(queryInstanceDomainStmt)
 	options.Write(&builder)
 
-	return scanInstanceDomain(ctx, i.client, &builder)
+	return scanInstanceDomain(ctx, client, &builder)
 }
 
 // List implements [domain.InstanceDomainRepository].
-// Subtle: this method shadows the method ([domain.InstanceRepository]).List of instanceDomain.instance.
-func (i *instanceDomain) List(ctx context.Context, opts ...database.QueryOption) ([]*domain.InstanceDomain, error) {
+func (i instanceDomain) List(ctx context.Context, client database.QueryExecutor, opts ...database.QueryOption) ([]*domain.InstanceDomain, error) {
 	options := new(database.QueryOpts)
 	for _, opt := range opts {
 		opt(options)
@@ -49,11 +56,11 @@ func (i *instanceDomain) List(ctx context.Context, opts ...database.QueryOption)
 	builder.WriteString(queryInstanceDomainStmt)
 	options.Write(&builder)
 
-	return scanInstanceDomains(ctx, i.client, &builder)
+	return scanInstanceDomains(ctx, client, &builder)
 }
 
 // Add implements [domain.InstanceDomainRepository].
-func (i *instanceDomain) Add(ctx context.Context, domain *domain.AddInstanceDomain) error {
+func (i instanceDomain) Add(ctx context.Context, client database.QueryExecutor, domain *domain.AddInstanceDomain) error {
 	var (
 		builder              database.StatementBuilder
 		createdAt, updatedAt any = database.DefaultInstruction, database.DefaultInstruction
@@ -69,33 +76,41 @@ func (i *instanceDomain) Add(ctx context.Context, domain *domain.AddInstanceDoma
 	builder.WriteArgs(domain.InstanceID, domain.Domain, domain.IsPrimary, domain.IsGenerated, domain.Type, createdAt, updatedAt)
 	builder.WriteString(`) RETURNING created_at, updated_at`)
 
-	return i.client.QueryRow(ctx, builder.String(), builder.Args()...).Scan(&domain.CreatedAt, &domain.UpdatedAt)
+	return client.QueryRow(ctx, builder.String(), builder.Args()...).Scan(&domain.CreatedAt, &domain.UpdatedAt)
 }
 
 // Update implements [domain.InstanceDomainRepository].
-// Subtle: this method shadows the method ([domain.InstanceRepository]).Update of instanceDomain.instance.
-func (i *instanceDomain) Update(ctx context.Context, condition database.Condition, changes ...database.Change) (int64, error) {
+func (i instanceDomain) Update(ctx context.Context, client database.QueryExecutor, condition database.Condition, changes ...database.Change) (int64, error) {
+	if !condition.IsRestrictingColumn(i.InstanceIDColumn()) {
+		return 0, database.NewMissingConditionError(i.InstanceIDColumn())
+	}
 	if len(changes) == 0 {
 		return 0, database.ErrNoChanges
 	}
-	var builder database.StatementBuilder
+	if !database.Changes(changes).IsOnColumn(i.UpdatedAtColumn()) {
+		changes = append(changes, database.NewChange(i.UpdatedAtColumn(), database.NullInstruction))
+	}
 
+	var builder database.StatementBuilder
 	builder.WriteString(`UPDATE zitadel.instance_domains SET `)
 	database.Changes(changes).Write(&builder)
 
 	writeCondition(&builder, condition)
 
-	return i.client.Exec(ctx, builder.String(), builder.Args()...)
+	return client.Exec(ctx, builder.String(), builder.Args()...)
 }
 
 // Remove implements [domain.InstanceDomainRepository].
-func (i *instanceDomain) Remove(ctx context.Context, condition database.Condition) (int64, error) {
-	var builder database.StatementBuilder
+func (i instanceDomain) Remove(ctx context.Context, client database.QueryExecutor, condition database.Condition) (int64, error) {
+	if !condition.IsRestrictingColumn(i.InstanceIDColumn()) {
+		return 0, database.NewMissingConditionError(i.InstanceIDColumn())
+	}
 
+	var builder database.StatementBuilder
 	builder.WriteString(`DELETE FROM zitadel.instance_domains WHERE `)
 	condition.Write(&builder)
 
-	return i.client.Exec(ctx, builder.String(), builder.Args()...)
+	return client.Exec(ctx, builder.String(), builder.Args()...)
 }
 
 // -------------------------------------------------------------
@@ -146,40 +161,38 @@ func (i instanceDomain) TypeCondition(typ domain.DomainType) database.Condition
 // -------------------------------------------------------------
 
 // CreatedAtColumn implements [domain.InstanceDomainRepository].
-// Subtle: this method shadows the method ([domain.InstanceRepository]).CreatedAtColumn of instanceDomain.instance.
-func (instanceDomain) CreatedAtColumn() database.Column {
-	return database.NewColumn("instance_domains", "created_at")
+func (i instanceDomain) CreatedAtColumn() database.Column {
+	return database.NewColumn(i.unqualifiedTableName(), "created_at")
 }
 
 // DomainColumn implements [domain.InstanceDomainRepository].
-func (instanceDomain) DomainColumn() database.Column {
-	return database.NewColumn("instance_domains", "domain")
+func (i instanceDomain) DomainColumn() database.Column {
+	return database.NewColumn(i.unqualifiedTableName(), "domain")
 }
 
 // InstanceIDColumn implements [domain.InstanceDomainRepository].
-func (instanceDomain) InstanceIDColumn() database.Column {
-	return database.NewColumn("instance_domains", "instance_id")
+func (i instanceDomain) InstanceIDColumn() database.Column {
+	return database.NewColumn(i.unqualifiedTableName(), "instance_id")
 }
 
 // IsPrimaryColumn implements [domain.InstanceDomainRepository].
-func (instanceDomain) IsPrimaryColumn() database.Column {
-	return database.NewColumn("instance_domains", "is_primary")
+func (i instanceDomain) IsPrimaryColumn() database.Column {
+	return database.NewColumn(i.unqualifiedTableName(), "is_primary")
 }
 
 // UpdatedAtColumn implements [domain.InstanceDomainRepository].
-// Subtle: this method shadows the method ([domain.InstanceRepository]).UpdatedAtColumn of instanceDomain.instance.
-func (instanceDomain) UpdatedAtColumn() database.Column {
-	return database.NewColumn("instance_domains", "updated_at")
+func (i instanceDomain) UpdatedAtColumn() database.Column {
+	return database.NewColumn(i.unqualifiedTableName(), "updated_at")
 }
 
 // IsGeneratedColumn implements [domain.InstanceDomainRepository].
-func (instanceDomain) IsGeneratedColumn() database.Column {
-	return database.NewColumn("instance_domains", "is_generated")
+func (i instanceDomain) IsGeneratedColumn() database.Column {
+	return database.NewColumn(i.unqualifiedTableName(), "is_generated")
 }
 
 // TypeColumn implements [domain.InstanceDomainRepository].
-func (instanceDomain) TypeColumn() database.Column {
-	return database.NewColumn("instance_domains", "type")
+func (i instanceDomain) TypeColumn() database.Column {
+	return database.NewColumn(i.unqualifiedTableName(), "type")
 }
 
 // -------------------------------------------------------------