chore: turn off profiling by default (#842)

Author: cdc-as81

Cargo.toml

@@ -77,7 +77,7 @@ homepage.workspace = true
 authors.workspace = true
 
 [features]
-default = ["logging", "progress_bar", "profiling"]
+default = ["logging", "progress_bar"]
 
 logging = ["log4rs", "fern", "wasm-bindgen", "web-sys"]
 progress_bar = ["dep:progress_bar", "anyhow"]

docs/book/src/examples.md

@@ -29,7 +29,7 @@ Demonstrates the profiling module: counting events, opening spans, computing
 statistics, and writing profiling data to JSON.
 
 ```sh
-cargo run --example profiling
+cargo run --example profiling --features profiling
 ```
 
 ## End-to-end Examples

docs/book/src/topics/profiling-module.md

@@ -8,8 +8,15 @@ Ixa includes a lightweight, feature-gated profiling module you can use to:
 - Write results to a JSON file along with execution statistics
 
 The API lives under `ixa::profiling` and is behind the `profiling` Cargo feature
-(enabled by default). If you disable the feature, the API becomes a no-op so you
-can leave profiling calls in your code.
+(disabled by default). If you do not enable the feature, the API becomes a no-op
+so you can leave profiling calls in your code.
+
+When running the built-in profiling example from the root crate, enable the
+feature explicitly:
+
+```sh
+cargo run --example profiling --features profiling
+```
 
 ## Example console output
 

examples/profiling/Cargo.toml

@@ -10,7 +10,7 @@ authors.workspace = true
 publish = false
 
 [dependencies]
-ixa = { path = "../../" }
+ixa = { path = "../../", features = ["profiling"] }
 serde_json.workspace = true
 
 [lints]

src/lib.rs

@@ -31,7 +31,7 @@
 //!
 //! - **`logging`**: enables structured logging for native and wasm targets.
 //! - **`progress_bar`**: enables the timeline progress bar for long-running simulations.
-//! - **`profiling`**: enables collection and reporting of execution profiling statistics.
+//! - **`profiling`**: enables collection and reporting of execution profiling statistics. Disabled by default.
 
 #![doc = include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/docs/book/src/cli-usage.md"))]
 

src/profiling/mod.rs

@@ -10,7 +10,7 @@
 //! - Computed statistics – define custom, derived metrics over collected data.
 //! - A default computed statistic, infection forecasting efficiency.
 //!
-//! Feature flag: all functionality is gated behind the `profiling` feature (enabled by default).
+//! Feature flag: all functionality is gated behind the `profiling` feature (disabled by default).
 //! When the feature is disabled, the public API remains available but becomes a no-op and gets
 //! optimized away by the compiler, so you can leave profiling calls in your code at zero cost.
 //!
@@ -173,7 +173,7 @@ pub use reporting::*;
 
 use crate::{error, Context, ContextReportExt};
 
-#[cfg(test)]
+#[cfg(all(test, feature = "profiling"))]
 /// Publicly expose access to profiling data only for testing.
 pub fn get_profiling_data() -> std::sync::MutexGuard<'static, ProfilingData> {
     profiling_data()

src/profiling/reporting.rs

@@ -51,8 +51,8 @@ pub trait ProfilingContextExt: ContextReportExt {
 }
 impl ProfilingContextExt for Context {}
 
-#[cfg(test)]
-mod tests {
+#[cfg(all(test, feature = "profiling"))]
+mod profiling_tests {
     use std::fs;
     use std::time::Duration;
 
@@ -183,3 +183,16 @@ mod tests {
         );
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::ProfilingContextExt;
+    use crate::context::Context;
+
+    #[test]
+    fn context_implements_profiling_extension() {
+        let mut context = Context::new();
+        context.print_execution_statistics(false);
+        context.write_profiling_data();
+    }
+}