feat: change panic to an error if cannot initialize libquil

lib/src/lib.rs

@@ -4,7 +4,7 @@
 
 use std::{
     ffi::{CStr, CString},
-    path::{Path, PathBuf},
+    path::PathBuf,
     str::Utf8Error,
     sync::Once,
 };
@@ -22,7 +22,7 @@ pub(crate) mod bindings {
 static START: Once = Once::new();
 
 #[derive(Debug, thiserror::Error)]
-enum Error {
+pub enum Error {
     #[error("Could not find libquil core file. Set the LIBQUIL_CORE_PATH environment variable.")]
     CoreFileNotFound,
 }
@@ -45,13 +45,11 @@ fn find_core_file() -> Result<String, Error> {
 }
 
 /// Initializes libquil using it's core image. No-op after the first call.
-pub(crate) fn init_libquil() {
+pub(crate) fn init_libquil() -> Result<(), Error> {
+    let core_path = find_core_file()?;
+
     START.call_once(|| {
-        let path = match find_core_file() {
-            Ok(path) => path,
-            Err(e) => panic!("{e}"),
-        };
-        let ptr = CString::new(path).unwrap().into_raw();
+        let ptr = CString::new(core_path).unwrap().into_raw();
 
         unsafe {
             // The library built by maturin does link to libquil, but
@@ -67,7 +65,9 @@ pub(crate) fn init_libquil() {
             bindings::init(ptr);
             let _ = CString::from_raw(ptr);
         }
-    })
+    });
+
+    Ok(())
 }
 
 pub(crate) fn handle_libquil_error(errno: libquil_error_t) -> Result<(), String> {

lib/src/quilc.rs

@@ -41,6 +41,8 @@ pub enum Error {
     ProgramString(String),
     #[error("invalid UTF-8 program: {0}")]
     ProgramUtf8(#[from] std::str::Utf8Error),
+    #[error("failed to initialize libquil: {0}")]
+    FailedToInitializeLibquil(#[from] crate::Error),
 }
 /// A quilc chip specification
 #[derive(Clone, Debug)]
@@ -54,7 +56,7 @@ impl TryFrom<CString> for Chip {
     type Error = Error;
 
     fn try_from(json: CString) -> Result<Self, Self::Error> {
-        crate::init_libquil();
+        crate::init_libquil()?;
 
         let ptr = json.into_raw();
         let mut chip: chip_specification = std::ptr::null_mut();
@@ -97,7 +99,7 @@ impl TryFrom<CString> for Program {
     type Error = Error;
 
     fn try_from(program: CString) -> Result<Self, Self::Error> {
-        init_libquil();
+        init_libquil()?;
 
         let ptr = program.into_raw();
         let mut parsed_program: quil_program = std::ptr::null_mut();
@@ -128,7 +130,7 @@ impl Drop for Program {
 
 impl Program {
     pub fn to_string(&self) -> Result<String, Error> {
-        init_libquil();
+        init_libquil()?;
 
         unsafe {
             let mut program_string_ptr: *mut std::os::raw::c_char = std::ptr::null_mut();
@@ -145,7 +147,7 @@ impl Program {
 
 /// Compiles the [`Program`] for the given [`Chip`]
 pub fn compile_program(program: &Program, chip: &Chip) -> Result<CompilationResult, Error> {
-    init_libquil();
+    init_libquil()?;
     let mut compiled_program: quil_program = std::ptr::null_mut();
 
     unsafe {
@@ -238,7 +240,8 @@ pub struct CompilationResult {
 /// Compiles the [`Program`] for the given [`Chip`] and restricts
 /// the resulting [`Program`] to satisfy "protoquil" constraints
 pub fn compile_protoquil(program: &Program, chip: &Chip) -> Result<CompilationResult, Error> {
-    init_libquil();
+    init_libquil()?;
+
     let mut compiled_program: quil_program = std::ptr::null_mut();
     let metadata_ptr: quilc_compilation_metadata = std::ptr::null_mut();
 
@@ -265,7 +268,8 @@ pub fn compile_protoquil(program: &Program, chip: &Chip) -> Result<CompilationRe
 
 /// Get a fully-connected 2Q [`Chip`]
 pub fn get_chip() -> Result<Chip, Error> {
-    init_libquil();
+    init_libquil()?;
+
     let mut chip: chip_specification = std::ptr::null_mut();
 
     unsafe {
@@ -278,7 +282,7 @@ pub fn get_chip() -> Result<Chip, Error> {
 
 /// Prints the given [`Program`] to stdout
 pub fn print_program(program: &Program) -> Result<(), Error> {
-    init_libquil();
+    init_libquil()?;
 
     unsafe {
         let err = quilc_print_program.unwrap()(program.0);
@@ -299,7 +303,7 @@ pub fn conjugate_pauli_by_clifford(
     pauli_terms: Vec<CString>,
     clifford: &Program,
 ) -> Result<ConjugatePauliByCliffordResult, Error> {
-    init_libquil();
+    init_libquil()?;
 
     unsafe {
         let mut phase = 0;
@@ -336,7 +340,7 @@ pub fn generate_rb_sequence(
     seed: Option<i32>,
     interleaver: Option<&Program>,
 ) -> Result<Vec<Vec<i32>>, Error> {
-    init_libquil();
+    init_libquil()?;
 
     let mut gateset = gateset.iter().map(|p| p.0).collect::<Vec<_>>();
     let mut results_ptr: *mut std::ffi::c_int = std::ptr::null_mut();
@@ -399,7 +403,7 @@ impl Display for VersionInfo {
 }
 
 pub fn get_version_info() -> Result<VersionInfo, Error> {
-    init_libquil();
+    init_libquil()?;
 
     unsafe {
         let mut version_info: quilc_version_info = std::ptr::null_mut();

lib/src/qvm.rs

@@ -28,6 +28,8 @@ pub enum Error {
     Wavefunction(String),
     #[error("failed to perform expectation: {0}")]
     Expectation(String),
+    #[error("failed to initialize libquil: {0}")]
+    FailedToInitializeLibquil(#[from] crate::Error),
 }
 
 #[derive(Debug)]
@@ -43,7 +45,7 @@ impl Display for VersionInfo {
 }
 
 pub fn get_version_info() -> Result<VersionInfo, Error> {
-    init_libquil();
+    init_libquil()?;
 
     unsafe {
         let mut version_info: qvm_version_info = std::ptr::null_mut();
@@ -144,7 +146,7 @@ pub fn multishot(
 ) -> Result<HashMap<String, Vec<Vec<u32>>>, Error> {
     let mut multishot = HashMap::new();
 
-    init_libquil();
+    init_libquil()?;
     let addresses: QvmMultishotAddresses = addresses.try_into()?;
     let mut result_ptr: qvm_multishot_result = std::ptr::null_mut();
 
@@ -205,7 +207,7 @@ pub fn multishot_measure(
     qubits: &[i32],
     trials: i32,
 ) -> Result<Vec<Vec<i32>>, Error> {
-    init_libquil();
+    init_libquil()?;
 
     // NOTE(mgsk): There might be a way for this to be a Vec<Vec<i32>>
     // which would exactly match our return type. In practice, however,
@@ -237,7 +239,7 @@ pub fn wavefunction(
     program: &quilc::Program,
     n_qubits: u32,
 ) -> Result<Vec<num_complex::Complex64>, Error> {
-    init_libquil();
+    init_libquil()?;
 
     let mut wavefunction = vec![0.0; 2 * 2u32.pow(n_qubits) as usize];
 
@@ -259,7 +261,7 @@ pub fn wavefunction(
 /// of finding the quantum state in `|i>`. For example, `v[2]` is the probability
 /// of finding the quantum state in `|10>`; `v[5]` the probability of `|101>`; etc.
 pub fn probabilities(program: &quilc::Program, n_qubits: u32) -> Result<Vec<f64>, Error> {
-    init_libquil();
+    init_libquil()?;
 
     let mut probabilities = vec![0.0; 2u32.pow(n_qubits) as usize];
 
@@ -277,7 +279,7 @@ pub fn expectation(
     program: &quilc::Program,
     operators: Vec<&quilc::Program>,
 ) -> Result<Vec<f64>, Error> {
-    init_libquil();
+    init_libquil()?;
 
     unsafe {
         let mut expectations = vec![0.0; operators.len()];