diff --git a/Cargo.toml b/Cargo.toml
index 2ce6f51..4ee6171 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,7 +7,7 @@ version = "0.14.2"
edition = "2024"
rust-version = "1.88"
description = "Automatic instrumentation-based profiler for Rust. Measures self-time, call counts, and heap allocations per function."
-license = "MIT"
+license = "GPL-3.0-only"
repository = "https://github.com/rocketman-code/piano"
keywords = ["profiling", "profiler", "instrumentation", "performance", "timing"]
categories = ["development-tools::profiling"]
diff --git a/LICENSE b/LICENSE
index 2688efb..d0656df 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,18 +1,689 @@
-MIT License
+piano - Automatic instrumentation-based profiler for Rust
+Copyright (C) 2026 Harnoor Lal
-Copyright (c) 2025-present Harnoor Lal
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, version 3.
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
-associated documentation files (the "Software"), to deal in the Software without restriction, including
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-copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the
-following conditions:
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
-The above copyright notice and this permission notice shall be included in all copies or substantial
-portions of the Software.
+You should have received a copy of the GNU General Public License
+along with this program. If not, see .
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
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-USE OR OTHER DEALINGS IN THE SOFTWARE.
+ GNU GENERAL PUBLIC LICENSE
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+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+ If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+ Later license versions may give you additional or different
+permissions. However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+ 15. Disclaimer of Warranty.
+
+ THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+ 16. Limitation of Liability.
+
+ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+
+ Copyright (C)
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see .
+
+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ Copyright (C)
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+.
diff --git a/README.md b/README.md
index 97e624d..7536f68 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
# piano
[](https://crates.io/crates/piano)
-[](LICENSE)
+[](LICENSE)
Automatic instrumentation-based profiler for Rust. Measures self-time, call counts, and heap allocations per function across sync, threaded, and async code.
@@ -160,4 +160,4 @@ The runtime has zero external dependencies to avoid conflicts with your project.
## License
-MIT
+GPLv3. See [LICENSE](LICENSE).
diff --git a/src/build.rs b/src/build.rs
index 26999f4..66fa096 100644
--- a/src/build.rs
+++ b/src/build.rs
@@ -8,6 +8,12 @@ use toml_edit::DocumentMut;
use crate::error::{Error, io_context};
+/// Which cargo target to build.
+pub enum CargoTarget<'a> {
+ Bin(&'a str),
+ Example(&'a str),
+}
+
// --- Cargo metadata types ---
#[derive(Debug, Deserialize)]
@@ -55,19 +61,20 @@ pub fn cargo_metadata(project_dir: &Path) -> Result {
.map_err(|e| Error::BuildFailed(format!("failed to parse cargo metadata: {e}")))
}
-/// Find a binary target in the metadata for the given package.
+/// Find a target of the given kind in the metadata for the given package.
///
-/// When `bin_name` is `Some`, looks for that specific binary target.
-/// When `None`, returns the first binary target found.
+/// `kind` is the cargo target kind: "bin" or "example".
+/// When `name` is `Some`, looks for that specific target.
+/// When `None`, returns the first target of that kind found.
///
/// Returns `(package_name, src_path)` where src_path is the absolute path
-/// to the binary's entry point.
-pub fn find_bin_target(
+/// to the target's entry point.
+pub fn find_target(
metadata: &CargoMetadata,
package_name: Option<&str>,
- bin_name: Option<&str>,
+ name: Option<&str>,
+ kind: &str,
) -> Result<(String, PathBuf), Error> {
- // Filter packages: if package_name given, match it; otherwise use all.
let candidates: Vec<&MetadataPackage> = if let Some(pkg) = package_name {
metadata.packages.iter().filter(|p| p.name == pkg).collect()
} else {
@@ -75,18 +82,18 @@ pub fn find_bin_target(
};
if candidates.is_empty() {
- let name = package_name.unwrap_or("");
+ let pkg = package_name.unwrap_or("");
return Err(Error::BuildFailed(format!(
- "no package '{name}' found in cargo metadata"
+ "no package '{pkg}' found in cargo metadata"
)));
}
for pkg in &candidates {
for target in &pkg.targets {
- if !target.kind.iter().any(|k| k == "bin") {
+ if !target.kind.iter().any(|k| k == kind) {
continue;
}
- if let Some(wanted) = bin_name {
+ if let Some(wanted) = name {
if target.name != wanted {
continue;
}
@@ -95,10 +102,10 @@ pub fn find_bin_target(
}
}
- let bin_desc = bin_name.unwrap_or("default");
+ let target_desc = name.unwrap_or("default");
let pkg_desc = package_name.unwrap_or("");
Err(Error::BuildFailed(format!(
- "no binary target '{bin_desc}' found in package '{pkg_desc}'"
+ "no {kind} target '{target_desc}' found in package '{pkg_desc}'"
)))
}
@@ -732,7 +739,7 @@ pub fn build_instrumented(
project_dir: &Path,
target_dir: &Path,
package: Option<&str>,
- bin: Option<&str>,
+ target: Option>,
config_path: &Path,
modified_files: &std::collections::HashSet,
) -> Result {
@@ -756,8 +763,14 @@ pub fn build_instrumented(
if let Some(pkg) = package {
cmd.arg("-p").arg(pkg);
}
- if let Some(bin_name) = bin {
- cmd.arg("--bin").arg(bin_name);
+ match target {
+ Some(CargoTarget::Bin(name)) => {
+ cmd.arg("--bin").arg(name);
+ }
+ Some(CargoTarget::Example(name)) => {
+ cmd.arg("--example").arg(name);
+ }
+ None => {}
}
let output = cmd.output()?;
@@ -936,7 +949,7 @@ edition = "2021"
}],
};
- let (name, path) = find_bin_target(&metadata, None, None).unwrap();
+ let (name, path) = find_target(&metadata, None, None, "bin").unwrap();
assert_eq!(name, "demo");
assert_eq!(path, PathBuf::from("/project/src/main.rs"));
}
@@ -963,7 +976,7 @@ edition = "2021"
}],
};
- let (name, path) = find_bin_target(&metadata, None, Some("worker")).unwrap();
+ let (name, path) = find_target(&metadata, None, Some("worker"), "bin").unwrap();
assert_eq!(name, "demo");
assert_eq!(path, PathBuf::from("/project/src/worker.rs"));
}
@@ -990,7 +1003,7 @@ edition = "2021"
}],
};
- let (_, path) = find_bin_target(&metadata, None, None).unwrap();
+ let (_, path) = find_target(&metadata, None, None, "bin").unwrap();
assert_eq!(path, PathBuf::from("/project/src/main.rs"));
}
@@ -1009,7 +1022,7 @@ edition = "2021"
}],
};
- let result = find_bin_target(&metadata, None, Some("nonexistent"));
+ let result = find_target(&metadata, None, Some("nonexistent"), "bin");
assert!(result.is_err());
let msg = result.unwrap_err().to_string();
assert!(
@@ -1044,11 +1057,49 @@ edition = "2021"
],
};
- let (name, path) = find_bin_target(&metadata, Some("core"), None).unwrap();
+ let (name, path) = find_target(&metadata, Some("core"), None, "bin").unwrap();
assert_eq!(name, "core");
assert_eq!(path, PathBuf::from("/ws/crates/core/src/main.rs"));
}
+ #[test]
+ fn find_target_finds_example() {
+ let metadata = CargoMetadata {
+ workspace_root: PathBuf::from("/project"),
+ packages: vec![MetadataPackage {
+ name: "demo".to_string(),
+ manifest_path: PathBuf::from("/project/Cargo.toml"),
+ targets: vec![
+ MetadataTarget {
+ name: "demo".to_string(),
+ kind: vec!["lib".to_string()],
+ src_path: PathBuf::from("/project/src/lib.rs"),
+ },
+ MetadataTarget {
+ name: "demo".to_string(),
+ kind: vec!["bin".to_string()],
+ src_path: PathBuf::from("/project/src/main.rs"),
+ },
+ MetadataTarget {
+ name: "bench".to_string(),
+ kind: vec!["example".to_string()],
+ src_path: PathBuf::from("/project/examples/bench.rs"),
+ },
+ ],
+ }],
+ };
+
+ let (name, path) = find_target(&metadata, None, Some("bench"), "example").unwrap();
+ assert_eq!(name, "demo");
+ assert_eq!(path, PathBuf::from("/project/examples/bench.rs"));
+
+ let result = find_target(&metadata, None, None, "example");
+ assert!(result.is_ok());
+
+ let result = find_target(&metadata, None, None, "bin");
+ assert_eq!(result.unwrap().1, PathBuf::from("/project/src/main.rs"));
+ }
+
#[test]
fn find_current_package_matches_dir() {
let tmp = TempDir::new().unwrap();
diff --git a/src/main.rs b/src/main.rs
index a356846..faaa123 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,8 +8,8 @@ use std::time::Duration;
use clap::{Parser, Subcommand};
use piano::build::{
- build_instrumented, cargo_metadata, clean_stale_piano_files, find_bin_target,
- find_current_package, find_project_root, prebuild_runtime, prebuild_runtime_from_path,
+ CargoTarget, build_instrumented, cargo_metadata, clean_stale_piano_files, find_current_package,
+ find_project_root, find_target, prebuild_runtime, prebuild_runtime_from_path,
};
use piano::error::{Error, io_context};
use piano::report::{
@@ -74,9 +74,13 @@ struct BuildOpts {
/// Build and profile a specific binary target (for projects with multiple
/// [[bin]] entries). Matches cargo's --bin flag.
- #[arg(long)]
+ #[arg(long, conflicts_with = "example")]
bin: Option,
+ /// Build and profile an example target. Matches cargo's --example flag.
+ #[arg(long, conflicts_with = "bin")]
+ example: Option,
+
/// Capture per-thread CPU time alongside wall time (Unix only).
#[arg(long)]
cpu_time: bool,
@@ -424,6 +428,7 @@ fn build_project(
project,
runtime_path,
bin,
+ example,
cpu_time,
output_dir,
list_skipped,
@@ -471,25 +476,25 @@ fn build_project(
))
})?;
- // Find the target package and binary.
- // If the user specified --bin, look for it. Otherwise find the current
- // package from the project directory.
- let (package_name, bin_src_path) = if bin.is_some() || metadata.packages.len() == 1 {
+ // Find the target package and binary/example.
+ let target_kind = if example.is_some() { "example" } else { "bin" };
+ let target_name = example.as_deref().or(bin.as_deref());
+ let (package_name, bin_src_path) = if target_name.is_some() || metadata.packages.len() == 1 {
let pkg_filter = if metadata.packages.len() == 1 {
None
} else {
find_current_package(&metadata, &project).map(|p| p.name.as_str())
};
- find_bin_target(&metadata, pkg_filter, bin.as_deref())?
+ find_target(&metadata, pkg_filter, target_name, target_kind)?
} else {
- // Multiple packages, no --bin: find the package matching project dir.
+ // Multiple packages, no --bin/--example: find the package matching project dir.
let pkg = find_current_package(&metadata, &project).ok_or_else(|| {
Error::BuildFailed(format!(
"could not determine which package to build in workspace at {}",
workspace_root.display()
))
})?;
- find_bin_target(&metadata, Some(&pkg.name), None)?
+ find_target(&metadata, Some(&pkg.name), None, "bin")?
};
// Derive source directory from the binary's src_path.
@@ -752,11 +757,16 @@ fn build_project(
} else {
None
};
+ let cargo_target = if let Some(ref ex) = example {
+ Some(CargoTarget::Example(ex.as_str()))
+ } else {
+ bin.as_deref().map(CargoTarget::Bin)
+ };
let binary = build_instrumented(
&workspace_root,
&target_dir,
pkg_arg,
- bin.as_deref(),
+ cargo_target,
&config_path,
&modified_files,
)?;
@@ -789,39 +799,45 @@ fn is_binary_extension(ext: &std::ffi::OsStr) -> bool {
fn find_latest_binary(project_root: &Option) -> Result {
let project = project_root.as_ref().ok_or(Error::NoBinary)?;
- let dir = project.join("target/piano/release");
- if !dir.is_dir() {
+ let release_dir = project.join("target/piano/release");
+ if !release_dir.is_dir() {
return Err(Error::NoBinary);
}
+ let mut dirs = vec![release_dir.clone()];
+ let examples_dir = release_dir.join("examples");
+ if examples_dir.is_dir() {
+ dirs.push(examples_dir);
+ }
let mut best: Option<(PathBuf, std::time::SystemTime)> = None;
- for entry in std::fs::read_dir(&dir).map_err(io_context("read directory", &dir))? {
- let entry = entry.map_err(io_context("read directory entry", &dir))?;
- let path = entry.path();
- if !path.is_file() {
- continue;
- }
- // Skip non-binary files by extension. On Unix, binaries have no extension.
- // On Windows, binaries have .exe extension -- allow those through.
- if let Some(ext) = path.extension() {
- if !is_binary_extension(ext) {
+ for dir in &dirs {
+ let entries = std::fs::read_dir(dir).map_err(io_context("read directory", dir))?;
+ for entry in entries {
+ let entry = entry.map_err(io_context("read directory entry", dir))?;
+ let path = entry.path();
+ if !path.is_file() {
continue;
}
- }
- let meta = entry
- .metadata()
- .map_err(io_context("read metadata", &path))?;
- #[cfg(unix)]
- {
- use std::os::unix::fs::PermissionsExt;
- if meta.permissions().mode() & 0o111 == 0 {
- continue; // not executable
+ if let Some(ext) = path.extension() {
+ if !is_binary_extension(ext) {
+ continue;
+ }
+ }
+ let meta = entry
+ .metadata()
+ .map_err(io_context("read metadata", &path))?;
+ #[cfg(unix)]
+ {
+ use std::os::unix::fs::PermissionsExt;
+ if meta.permissions().mode() & 0o111 == 0 {
+ continue;
+ }
+ }
+ let mtime = meta
+ .modified()
+ .map_err(io_context("read modified time", &path))?;
+ if best.as_ref().is_none_or(|(_, t)| mtime > *t) {
+ best = Some((path, mtime));
}
- }
- let mtime = meta
- .modified()
- .map_err(io_context("read modified time", &path))?;
- if best.as_ref().is_none_or(|(_, t)| mtime > *t) {
- best = Some((path, mtime));
}
}
best.map(|(p, _)| p).ok_or(Error::NoBinary)
diff --git a/src/rewrite/mod.rs b/src/rewrite/mod.rs
index 8ac6600..60403df 100644
--- a/src/rewrite/mod.rs
+++ b/src/rewrite/mod.rs
@@ -67,8 +67,9 @@ pub fn instrument_source(
continue;
};
let Some(body) = func.body() else { continue };
- let Some(name) = func.name() else { continue };
- let fn_name = name.text().to_string();
+ let Some(fn_name) = qualified_fn_name(&func) else {
+ continue;
+ };
// Shutdown: inject lifecycle into fn main()
if fn_name == "main" {
@@ -169,6 +170,26 @@ fn brace_offset_after_inner_attrs(stmt_list: &ast::StmtList) -> Result Option {
+ let bare = func.name()?.text().to_string();
+ let mut node = func.syntax().parent();
+ while let Some(n) = node {
+ if let Some(imp) = ast::Impl::cast(n.clone()) {
+ let self_ty = imp.self_ty()?;
+ let impl_name = crate::naming::render_impl_name(&self_ty, imp.trait_().as_ref());
+ return Some(format!("{impl_name}::{bare}"));
+ }
+ if ast::Fn::can_cast(n.kind()) {
+ break;
+ }
+ node = n.parent();
+ }
+ Some(bare)
+}
+
/// Check if a function's return type contains `impl Future`.
fn returns_impl_future(func: &ast::Fn) -> bool {
let Some(ret) = func.ret_type() else {
@@ -467,8 +488,9 @@ fn inject_guards_into_expansion(expanded: &str, measured: &HashMap)
continue;
};
let Some(body) = func.body() else { continue };
- let Some(name) = func.name() else { continue };
- let fn_name = name.text().to_string();
+ let Some(fn_name) = qualified_fn_name(&func) else {
+ continue;
+ };
let Some(&name_id) = measured.get(&fn_name) else {
continue;
@@ -633,7 +655,8 @@ mod tests {
#[test]
fn instruments_trait_method_impl() {
let source = "struct S;\nimpl std::fmt::Display for S {\n fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {\n write!(f, \"S\")\n }\n}\n";
- let measured: HashMap = [("fmt".into(), 0)].into_iter().collect();
+ let measured: HashMap =
+ [("::fmt".into(), 0)].into_iter().collect();
let result = instrument_source(source, &measured, None).unwrap();
assert!(result.source.contains("piano_runtime::enter(0)"));
}
@@ -671,7 +694,7 @@ mod tests {
#[test]
fn instruments_inherent_impl_method() {
let source = "struct S;\nimpl S {\n fn method(&self) {\n let x = 1;\n }\n}\n";
- let measured: HashMap = [("method".into(), 0)].into_iter().collect();
+ let measured: HashMap = [("S::method".into(), 0)].into_iter().collect();
let result = instrument_source(source, &measured, None).unwrap();
assert!(result.source.contains("piano_runtime::enter(0)"));
assert!(
@@ -903,10 +926,10 @@ m!();
let measured: HashMap = [
("free".into(), 0),
("in_module".into(), 1),
- ("inherent_method".into(), 2),
+ ("S::inherent_method".into(), 2),
("trait_default".into(), 3),
- ("trait_impl".into(), 4),
- ("trait_abstract".into(), 5),
+ ("::trait_impl".into(), 4),
+ ("::trait_abstract".into(), 5),
("nested".into(), 6),
("outer".into(), 7),
("macro_fn".into(), 8),
diff --git a/src/wrapper.rs b/src/wrapper.rs
index 136b24a..9b9f4ca 100644
--- a/src/wrapper.rs
+++ b/src/wrapper.rs
@@ -136,7 +136,10 @@ pub fn run_wrapper(config_path: &str) -> i32 {
let has_target = config.targets.contains_key(&source_key);
if !has_target && !is_entry_point {
- return exec_rustc(real_rustc, &rustc_args);
+ let source_parent = source_key.parent().unwrap_or(Path::new(""));
+ if !config.targets.keys().any(|t| t.starts_with(source_parent)) {
+ return exec_rustc(real_rustc, &rustc_args);
+ }
}
let crate_name = parsed.crate_name.as_deref().unwrap_or("unknown");
diff --git a/tests/workspace_layout.rs b/tests/workspace_layout.rs
index b0648cb..ea1953f 100644
--- a/tests/workspace_layout.rs
+++ b/tests/workspace_layout.rs
@@ -245,6 +245,134 @@ fn work() -> u64 {
.unwrap();
}
+/// Create a single-package project with both `[lib]` and `[[bin]]` targets.
+/// The library crate (`src/lib.rs`) re-exports a `compute` module containing
+/// functions. The binary (`src/bin/main.rs`) calls those library functions.
+/// This layout triggers the wrapper gate bug: `lib.rs` has no functions itself,
+/// so it is not in `config.targets`, causing the wrapper to skip the entire
+/// library crate and leaving `compute::add` / `compute::multiply`
+/// uninstrumented.
+fn create_lib_bin_package(root: &Path) {
+ fs::create_dir_all(root.join("src/compute")).unwrap();
+ fs::create_dir_all(root.join("src/bin")).unwrap();
+
+ fs::write(
+ root.join("Cargo.toml"),
+ r#"[package]
+name = "libbin"
+version = "0.1.0"
+edition = "2024"
+
+[[bin]]
+name = "libbin"
+path = "src/bin/main.rs"
+"#,
+ )
+ .unwrap();
+
+ fs::write(root.join("src/lib.rs"), "pub mod compute;\n").unwrap();
+
+ fs::write(
+ root.join("src/compute/mod.rs"),
+ r#"pub fn add(a: u64, b: u64) -> u64 {
+ a + b
+}
+
+pub fn multiply(a: u64, b: u64) -> u64 {
+ a * b
+}
+"#,
+ )
+ .unwrap();
+
+ fs::write(
+ root.join("src/bin/main.rs"),
+ r#"fn main() {
+ let product = libbin::compute::multiply(5, 6);
+ let sum = libbin::compute::add(5, 7);
+ println!("{product} {sum}");
+}
+"#,
+ )
+ .unwrap();
+}
+
+#[test]
+fn single_package_lib_bin_instruments_library_functions() {
+ let tmp = tempfile::tempdir().unwrap();
+ let project_dir = tmp.path().join("libbin");
+ create_lib_bin_package(&project_dir);
+
+ common::prepopulate_deps(&project_dir, common::mini_seed());
+
+ let piano_bin = env!("CARGO_BIN_EXE_piano");
+ let manifest_dir = Path::new(env!("CARGO_MANIFEST_DIR"));
+ let runtime_path = manifest_dir.join("piano-runtime");
+
+ let output = Command::new(piano_bin)
+ .args(["build", "--project"])
+ .arg(&project_dir)
+ .arg("--runtime-path")
+ .arg(&runtime_path)
+ .output()
+ .expect("failed to run piano build");
+
+ let stderr = String::from_utf8_lossy(&output.stderr);
+ let stdout = String::from_utf8_lossy(&output.stdout);
+
+ assert!(
+ output.status.success(),
+ "piano build failed:\nstderr: {stderr}\nstdout: {stdout}"
+ );
+
+ let binary_path = stdout.trim();
+ let runs_dir = tmp.path().join("runs");
+ fs::create_dir_all(&runs_dir).unwrap();
+
+ let run_output = Command::new(binary_path)
+ .env("PIANO_RUNS_DIR", &runs_dir)
+ .output()
+ .expect("failed to run instrumented binary");
+
+ assert!(
+ run_output.status.success(),
+ "instrumented binary failed:\n{}",
+ String::from_utf8_lossy(&run_output.stderr)
+ );
+
+ let program_stdout = String::from_utf8_lossy(&run_output.stdout);
+ assert!(
+ program_stdout.contains("30 12"),
+ "program should produce '30 12', got: {program_stdout}"
+ );
+
+ let run_file = common::largest_ndjson_file(&runs_dir);
+ let content = fs::read_to_string(&run_file).unwrap();
+ let stats = common::aggregate_ndjson(&content);
+
+ // Library functions should be instrumented even though lib.rs itself
+ // has no functions (only `pub mod compute;`).
+ assert!(
+ stats.contains_key("compute::add"),
+ "library function 'compute::add' should be instrumented, got keys: {:?}",
+ stats.keys().collect::>()
+ );
+ assert!(
+ stats["compute::add"].calls >= 1,
+ "compute::add should have at least 1 call"
+ );
+
+ assert!(
+ stats.contains_key("compute::multiply"),
+ "library function 'compute::multiply' should be instrumented, got keys: {:?}",
+ stats.keys().collect::>()
+ );
+ assert!(
+ stats["compute::multiply"].calls >= 1,
+ "compute::multiply should have at least 1 call"
+ );
+}
+
/// Create a workspace with two member crates (cli and lib-user), each with
/// its own binary. This exercises the multi-package branch in build dispatch
/// that the single-member tests above skip.