unchecked-io/docs/build-cleanup-chrono.md

Technical Task: Build Fixes & Profiler Cleanup Date: 2025-11-21 Goal: Fix PyPI build failures and remove heavy profiling code from production wheels.

1. Fix PyPI Build Failure (chrono-tz) Issue: The build fails on Linux/Mac/Windows CI because chrono-tz requires complex C-bindings that are often missing in standard Python environments. Analysis: UncheckedIO returns Apache Arrow RecordBatch objects (where timestamps are raw i64). We do not need pyo3 to convert Rust chrono types directly to Python datetime objects. The chrono-tz feature in pyo3 is dead weight causing build failures.

Action: Update Cargo.toml to remove the conflicting feature.

Ini, TOML

Cargo.toml

OLD

pyo3 =

NEW (Remove "chrono-tz")

pyo3 = { version = "0.27.1", features = ["extension-module"] } 2. Productionize the Profiler (Remove Tracy) Issue: The tracy-client and tracing-tracy crates add significant binary size and runtime overhead. They should not be present in the production library installed by users. Solution: Use Rust Feature Flags to make profiling "opt-in" for development only.

Step A: Update Cargo.toml Define a profiling feature and make the heavy dependencies optional.

Ini, TOML

[features] default = []

The "profiling" feature enables these two optional crates

profiling = ["dep:tracing-tracy", "dep:tracy-client"]

[dependencies]

Keep this (Lightweight facade)

tracing = "0.1.41"

Make these OPTIONAL (Heavy implementation)

tracing-tracy = { version = "0.11.2", optional = true } tracy-client = { version = "0.17.6", optional = true }

... other dependencies ...

Step B: Update src/lib.rs Wrap the profiler initialization logic so it only compiles when the flag is active.

Rust

// src/lib.rs

#[pymodule] fn unchecked_io(py: Python<'>, m: &Bound<'_, PyModule>) -> PyResult<()> {

// --- START PROFILER LOGIC ---
// This block now ONLY compiles if you run with `--features profiling`
#[cfg(feature = "profiling")] 
{
    use tracing_subscriber::layer::SubscriberExt;
    use tracing_subscriber::util::SubscriberInitExt;
    
    // Initialize the Tracy layer
    let _ = tracing_subscriber::registry()
        .with(tracing_tracy::TracyLayer::default())
        .try_init();
        
    println!("--- UncheckedIO: Profiling Enabled (Tracy) ---");
}
// --- END PROFILER LOGIC ---

m.add_function(wrap_pyfunction!(load_data_from_config, m)?)?;
m.add_function(wrap_pyfunction!(to_pandas_dataframe, m)?)?;
m.add_function(wrap_pyfunction!(profile_data, m)?)?;
Ok(())

} 3. How to Build For Development (With Profiler): Use this when you want to see the tracks in the Tracy GUI.

Bash

maturin develop --features profiling For Production / PyPI (Zero Overhead): This builds the "clean" version for users. The profiler code is stripped out entirely.

Bash

maturin publish