dagx/CHANGELOG.md

Changelog

All notable changes to dagx will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

Fixed

• Now able to return bare tuples as task outputs
• No longer able to create a DAG with cyclic dependencies (#3)
• The #[task] macro no longer requires an explicit return type (#2)

Changed

• Task inputs no longer need to be Clone (#7)
• Building a DAG is now a single-threaded operation (#12)
• Running a DAG now consumes the DagRunner and returns a DagOutput from which to get results (#12)
• #[task] macro support is now gated behind the derive default feature
• Tasks now receive input via the TaskInput type, which guarantees via the public API that dependencies can be extracted (#7)
• Task outputs are now extracted as owned values, not clones of an Arc value (#7)

Internal

• The task_fn macro has been extracted to the dagx-test crate
• Task inputs are passed to tasks directly from the runner, not through channels (#1)
• Redundant tests/examples/benchmarks removed to lower maintenance and refactor burden (#11)
• parking_lot dependency removed (#12)
• futures dependency replaced with futures-util (#8)

0.3.1 - 2025-10-10

View changes

Fixed

• Custom types now work automatically! The #[task] macro now generates inline extract_and_run() methods with type-specific extraction logic. This means ANY type implementing Clone + Send + Sync + 'static works automatically without implementing any special traits.
  • Previously, only types with ExtractInput implementations worked (primitives, String, Vec, HashMap, etc.)
  • Now, custom user types work seamlessly - just derive Clone and you're good to go!
  • No ExtractInput trait implementation needed for custom types
  • Nested structs, collections of custom types, and complex type hierarchies all work out of the box
  • New example: examples/custom_types.rs demonstrating custom types flowing through a DAG

Changed

• Documentation improvements
  • Updated README.md to highlight custom type support as a key feature
  • Added "Custom Types" section to Core Concepts with examples
  • Added custom_types.rs to the examples list
  • Updated feature list to emphasize "Works with ANY type"

Internal

• ExtractInput trait is now only used by the internal task_fn test helper
• The #[task] macro generates custom extraction logic per task, bypassing ExtractInput entirely
• This architectural change enables ANY type to work without requiring trait implementations

0.3.0 - 2025-10-08

View changes

Added

• Compile-time cycle prevention proof via new src/cycle_prevention.rs module

  • Comprehensive documentation with compile_fail tests proving cycles are impossible
  • New integration test suite tests/cycle_prevention.rs demonstrating type-state pattern
  • Documents how the type system prevents cycles at compile-time (zero runtime cost)
  • Added prominent documentation section in README.md explaining the feature

• New DagError::ConcurrentExecution variant

  • Replaces misuse of CycleDetected for concurrent run protection
  • More semantically accurate error reporting

Removed - BREAKING CHANGES

• Removed DagError::CycleDetected error variant
  • Cycles are provably impossible via the public API due to type-state pattern
  • Removed 24 lines of unreachable cycle detection code from runner.rs
  • Migration: If you were handling DagError::CycleDetected, remove that match arm
  • This error could never occur in practice, so no runtime behavior changes

Changed

• Documentation improvements

  • Added comprehensive "Compile-Time Cycle Prevention" section to README.md
  • Updated lib.rs documentation to highlight cycle prevention as first feature
  • Fixed rustdoc links in src/cycle_prevention.rs
  • Updated all error documentation references (removed cycle detection)
  • Added code examples demonstrating type-state pattern
  • Updated tagline to emphasize compile-time cycle prevention

• Test coverage improvements

  • Added #[cfg(not(tarpaulin_include))] to untestable type alias
  • Coverage at ~83% after removing dead code (target set to 80%)
  • Remaining uncovered lines are primarily tracing macros and unreachable error paths

• Enhanced CI configuration (.github/workflows/ci.yml)

  • MSRV verification now tests all 3 feature combinations (no-default, all, default)
  • Test matrix expanded to 18 runs (3 platforms × 2 Rust versions × 3 feature combos)
  • New cargo check job for all feature combinations
  • Lint (clippy) now runs on all feature combinations
  • Doc generation for all feature combinations
  • Coverage threshold set to 80% (accounts for tracing macros and unreachable error paths)

• Release check script improvements (scripts/release_check.sh)

  • Now reads MSRV from Cargo.toml instead of hardcoded version
  • Uses cargo msrv verify for all feature combinations
  • Tests all feature combinations (no-default, all, default)
  • Runs clippy, check, and tests on all feature combos
  • Includes coverage verification with 80% threshold

Fixed

• Clippy lints in test code

  • Removed unnecessary .clone() call on Copy type in tests/cycle_prevention.rs
  • Removed unnecessary borrow in test dependency wiring

• Flaky timing test on macOS CI

  • Increased timeout threshold from 140ms to 200ms in test_arc_parallel_execution
  • macOS CI runners are significantly slower than Linux/Windows
  • 200ms threshold still proves parallelism while accounting for CI variability

0.2.3 - 2025-10-08

View changes

Added

• Optional tracing support via tracing feature flag
  • Zero-cost when disabled (literally 0ns overhead - code removed at compile time)
  • Structured logging at INFO, DEBUG, TRACE, and ERROR levels
  • Instrumentation for DAG construction, execution, and error paths
  • New example: examples/tracing_example.rs demonstrating usage
  • Comprehensive test coverage in tests/tracing/ for both with/without feature
  • Follows same pattern as tokio/hyper for performance-critical libraries
  • Updated documentation in README.md and lib.rs

Changed

• Improved examples/04_parallel_computation.rs to actually prove parallelism
  • Now compares parallel vs sequential execution with timing measurements
  • Calculates and displays speedup ratio (e.g., "4.0x faster")
  • Clarifies difference from basic fan-in pattern in 03_fan_in.rs
  • Added warnings for debug builds with low speedup

Fixed

• Fixed broken ASCII diagram in examples/04_parallel_computation.rs

0.2.2 - 2025-10-07

View changes

Fixed

• Fixed README.md to reference correct crate version (0.2 instead of 0.1)
• Enhanced release check script to validate version consistency in documentation
  • Automatically extracts major.minor version and verifies documentation matches

0.2.1 - 2025-10-07

View changes

Fixed

• Fixed test execution on macOS by forcing tokio::test to use multi-threaded runtime
  • Ensures tests pass consistently across all platforms

0.2.0 - 2025-10-08

View changes

Changed

• BREAKING: Updated MSRV (Minimum Supported Rust Version) from 1.78.0 to 1.81.0
  • Required by updated dependencies: criterion@0.7.0, half@2.6.0, rayon@1.11.0
  • Updated in both dagx and dagx-macros crates
  • Updated all documentation (README.md, CONTRIBUTING.md)

Added

• Comprehensive test coverage improvements (82.61% → 92.94%)
  • Added 9 new unit tests for error paths in ExtractInput implementations
  • Added 3 new type conversion tests in src/types/tests.rs
  • Added 1 new trait implementation test in src/task/tests.rs
  • Added 1 new dependency tuple test in src/deps/tests.rs
  • Added 6 new execution path tests in tests/execution/basic.rs
  • Added error handling tests for HashMap, Result, Option, Vec, and Arc types
  • Added tests for tuple dependency count validation
  • Improved concurrent run protection test with better synchronization
• Added tarpaulin_include to lint configuration for coverage tooling compatibility

Fixed

• Fixed GitHub Actions cargo-audit workflow
  • Replaced deprecated actions-rs/audit-check@v1 with direct cargo audit command
  • Resolved "Resource not accessible by integration" error
• Fixed clippy warnings in test code
  • Removed unnecessary borrows in .depends_on() calls
  • Added #[allow(clippy::clone_on_copy)] for explicit clone test
• Marked timing-sensitive and resource-intensive tests with #[cfg_attr(tarpaulin, ignore)]
  • test_arc_parallel_execution (timing unreliable under instrumentation)
  • test_100000_nodes_stress (resource intensive)
  • test_10000_level_chain_stress (resource intensive)

Internal

• Improved test organization following existing patterns in tests/ directory
• Enhanced error path coverage for all ExtractInput trait implementations
• Better separation between unit tests and integration tests
• Refactored scripts/release_check.sh to use configurable VERSION variable
  • Replaced hardcoded version references throughout script
  • Updated instructions to use jj commands instead of git
  • Simplified version bumps for future releases

0.1.0 - 2025-10-05

Added

Core Features

• Type-safe async DAG executor with compile-time dependency validation
• Runtime-agnostic design (works with Tokio, async-std, smol, and other runtimes)
• Fluent builder API with type-state pattern for compile-time safety
• Comprehensive error handling with DagResult<T> and DagError enum
• Support for up to 8 dependencies per task
• True parallel execution with automatic task spawning

Task Patterns

• Stateless tasks: Pure functions with no self parameter
• Read-only state: Tasks with &self for configuration
• Mutable state: Tasks with &mut self for stateful operations
• Sync and async: Both synchronous and asynchronous task execution
• Procedural macro: #[task] macro for ergonomic task definitions

Error Handling

• Cycle detection with detailed node information
• Type-safe handle validation
• Panic isolation and conversion to errors
• Actionable error messages with recovery suggestions

Testing

• Comprehensive unit tests covering core functionality
• Documentation tests ensuring examples compile and run
• Panic handling and isolation tests
• Type safety verification tests
• Concurrency stress tests
• Integration tests for end-to-end workflows
• Runtime compatibility tests (Tokio, async-std, smol)
• Quirky runtime tests (async-executor, pollster, futures-executor)
• Dependency tuple tests (1-8 dependency support)
• Large DAG scalability tests (10,000+ nodes)

Performance

• Benchmark suite using Criterion
• True parallel execution (tasks spawn to multiple threads)
• Linear scaling verified up to 10,000+ tasks
• ~1-2µs overhead per task
• Efficient memory usage (~200 bytes per task)
• Zero-cost abstractions via generics and monomorphization

Documentation

• Comprehensive API documentation
• Tutorial examples (numbered, beginner-friendly):
  • 01_basic.rs - Getting started
  • 02_fan_out.rs - 1→N dependencies
  • 03_fan_in.rs - N→1 dependencies
  • 04_parallel_computation.rs - Parallel map-reduce
• Reference examples (practical patterns):
  • complex_dag.rs - Multi-layer workflows
  • conditional_workflow.rs - Conditional execution
  • data_pipeline.rs - ETL pipeline pattern
  • error_handling.rs - Error propagation and recovery
  • timeout.rs - Task timeouts
  • large_dag.rs - Scalability demonstration
  • parallelism_proof.rs - True parallelism proof
• Architecture documentation
• Security policy
• Contributing guidelines

Dependencies

• futures = "0.3" (runtime-agnostic async)
• parking_lot = "0.12" (efficient synchronization)
• dagx-macros (procedural macros)

Dev Dependencies

• tokio = "1" (async runtime)
• async-std = "1" (async runtime)
• smol = "2" (async runtime)
• criterion = "0.7" (benchmarking)
• async-executor = "1.13" (quirky runtime testing)
• pollster = "0.4" (quirky runtime testing)
• futures-executor = "0.3" (quirky runtime testing)

Tested Platforms

• Linux (primary development and CI)
• macOS (compatible)
• Windows (compatible)