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DataLinq v0.5.4 - Critical Memory Leak Fixes & Schema Generation Improvements
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@bazer bazer released this 11 Jun 23:14
· 41 commits to master since this release
0.5.4
fc34d96

This is a high-priority maintenance and enhancement release focused on resolving critical memory leaks, improving the fidelity of the schema-to-model generation process, and giving developers more control over their code generation workflow.

🚀 Highlights

  • Fixed Two Critical Memory Leaks: Identified and resolved two separate memory leaks related to cache clearing and event handling, drastically improving long-term stability and performance for applications under load.
  • Greatly Improved Database-to-C# Type Mapping: The create-models CLI tool is now much smarter, correctly generating unsigned types (uint, ulong, byte, etc.) and appropriately sized integer types (short, long) from MySQL/MariaDB schemas.
  • New --overwrite-types CLI Flag: Added a new powerful option to the create-models command that allows developers to force the regeneration of C# property types directly from the database schema, perfect for a "schema-first" workflow.

🐛 Critical Bug Fixes

  • Fixed Major Memory Leak in Relation Caching:
    • The previous event handling system for cache notifications (WeakEventManager) had a subtle flaw that prevented ImmutableRelation and ImmutableForeignKey objects from being garbage collected. This could lead to significant memory consumption over time.
    • Solution: The WeakEventManager has been completely replaced with a new, highly performant, lock-free CacheNotificationManager. This new system uses a custom array-swapping pattern with Interlocked.CompareExchange to ensure thread-safety and memory-safety without the overhead of reflection or the risks of finalizers, completely curing the leak.
  • Fixed Memory Leak in Index Cache:
    • A bug was discovered where calling TableCache.ClearCache() would not fully clear the IndexCache. The reverse mapping dictionary (primaryKeysToForeignKeys) was not being cleared, causing it to grow indefinitely. This has been fixed.
  • Corrected Nullability for Generated Properties:
    • Auto-incrementing primary key columns are now correctly generated with nullable C# types (e.g., int?) to reflect their null state before an entity is inserted into the database.
    • Columns with a DEFAULT value in the database are also now correctly generated as nullable, as the value is optional on insert.

✨ Features & Enhancements

  • Enhanced Schema-to-Model Type Mapping:
    • The MetadataFromMySqlFactory now correctly maps database integer types to their corresponding C# types based on size and UNSIGNED flags. This improves type safety and correctness when generating models from a MySQL/MariaDB database. The new mappings include:
      MySQL Type C# Type
      TINYINT UNSIGNED byte
      TINYINT sbyte
      SMALLINT UNSIGNED ushort
      SMALLINT short
      INT UNSIGNED uint
      INT int
      BIGINT UNSIGNED ulong
      BIGINT long
  • New --overwrite-types CLI Flag:
    • The datalinq create-models command now accepts an --overwrite-types flag.
    • Default Behavior: DataLinq preserves user-defined types in source code (like custom classes or enums) even if the underlying database column is a primitive type.
    • New Behavior: When --overwrite-types is used, DataLinq will force C# property types to be updated based on the schema from the database. This is ideal for when you change a column type in the database (e.g., from INT to BIGINT) and want your C# model to automatically update. This override intelligently preserves user-defined enum types and other custom classes.
  • Improved CLI Filtering Logic:
    • Unified the Tables and Views configuration lists in datalinq.json into a single, more intuitive Include list. If the list is empty or omitted, all tables and views are included. Otherwise, only the specified items are included.

🛠️ Internal Improvements & Testing

  • Improved Test Isolation: Created new, dedicated test fixtures (MySqlFilteringTestFixture, MySqlTypeMappingFixture) that create temporary databases. This ensures that tests for metadata parsing are fully isolated, faster, and more reliable.
  • Comprehensive Test Coverage: Added a full suite of unit tests for the new type mapping logic, CLI filtering behavior, and the --overwrite-types feature to prevent future regressions.

Full Changelog: 0.5.3...0.5.4

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