Diesel 2.3.0

This release includes a several large extensions to the query DSL provided by Diesel and also helps increases the number of platforms you can use Diesel on out of the box. Notable changes include:

• Improved query construction via #[derive(HasQuery)]
• Added support for window functions
• Using SQLite with WASM in your browser
• Extended support for various types, functions and operators in the PostgreSQL backend
• Support for JSON and JSONB in the SQLite backend

See the release blog for the full announcement

You can support the development of Diesel by:

• Contributing Code, Documentation or Guides. Checkout the planing for Diesel 2.4 for open tasks.
• Providing knowledge and help to maintain the MySQL/MariaDB backend. This is currently the only in-tree backend that is not used by any maintainers, so having someone around that actually uses this backend would be very helpful for the Diesel project.
• Answering questions in our discussion forum
• Reporting bugs in our issue tracker
• Helping triaging issues in our issue tracker
• Sponsoring the maintainers.

Added

• Added limit() and offset() DSL to combination clauses such as UNION
• Fixed #[derive(Identifiable)] ignoring attribute #[diesel(serialize_as)] on primary keys
• Added embedded struct support for AsChangeset via #[diesel(embed)]
• Added a #[diesel(skip_update)] attribute for the AsChangeset derive to skip updating a field present in the struct
• Support for libsqlite3-sys 0.35.0
• Add support for built-in PostgreSQL range operators and functions
• Support for postgres multirange type
• Added diesel::r2d2::TestCustomizer, which allows users to customize their diesel::r2d2::Pools
  in a way that makes the pools suitable for use in parallel tests.
• Added support for built-in PostgreSQL range operators and functions
• Added support for various built-in PostgreSQL array functions
• Added Json and Jsonb support for the SQLite backend.
• Added a #[diesel::declare_sql_function] attribute macro to easily define support for
  multiple sql functions at once via an extern "SQL" block
• Support [print_schema] allow_tables_to_appear_in_same_query_config = "fk_related_tables" to generate separate allow_tables_to_appear_in_same_query! calls containing only tables that are related through foreign keys. (Default: "all_tables".) It is not possible to build queries using two tables that don't appear in the same allow_tables_to_appear_in_same_query! call, but that macro generates O(n²) rust code, so this option may be useful to reduce compilation time. (#4333)
• Added wasm32-unknown-unknown target support for sqlite backend.
• Add support for the CAST operator
• Support [print_schema] allow_tables_to_appear_in_same_query_config = "none" to generate no allow_tables_to_appear_in_same_query! calls. (Default: "all_tables".). (#4333)
• Add [print_schema] pg_domains_as_custom_types parameter to generate custom types for PostgreSQL domains that matches any of the regexes in the given list. (Default: [].) This option allows an application to selectively give special meaning for the serialization/deserialization of these types, avoiding the default behavior of treating the domain as the underlying type. (#4592)
• Add support for batch insert and upsert statements with returning for SQLite
• Add support for window functions and aggregate expressions.

Fixed

• Fixed diesel thinking a.eq_any(b) was non-nullable even if a and b were nullable.
• Generate InstrumentationEvent::BeginTransaction for immediate and exclusive transactions in SQLite
• Use a single space instead of two spaces between DELETE FROM.
• Diesel CLI now ensures that migration versions are always unique. If it fails to generate a unique version, it will return an error. The new version format remains compatible with older Diesel versions.
• Updated ipnetwork to allow version 0.21.

Changed

• Use distinct DIESEL_LOG logging filter env variable instead of the default RUST_LOG one (#4575)
• The minimal supported Rust version is now 1.86.0

Full Changelog: v2.2.0...v2.3.0