Fix abi3 wheel build when no Python interpreters found

Changelog.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Allow user to override default Emscripten settings in [#1059](https://github.com/PyO3/maturin/pull/1059)
 * Enable `--crate-type cdylib` on Rust 1.64.0 in [#1060](https://github.com/PyO3/maturin/pull/1060)
 * Update MSRV to 1.59.0 in [#1071](https://github.com/PyO3/maturin/pull/1071)
+* Fix abi3 wheel build when no Python interpreters found in [#1072](https://github.com/PyO3/maturin/pull/1072)
 
 ## [0.13.2] - 2022-08-14
 

src/build_options.rs

@@ -403,18 +403,28 @@ impl BuildOptions {
                         bail!("Failed to find a python interpreter");
                     }
                 } else {
-                    let interpreters = find_interpreter_in_host(
+                    let found_interpreters = find_interpreter_in_host(
                         bridge,
                         interpreter,
                         target,
                         Some(*minor as usize),
                     )
-                    .unwrap_or_else(|_| {
-                        find_interpreter_in_sysconfig(interpreter, target, Some(*minor as usize))
-                            .unwrap_or_default()
-                    });
+                    .or_else(|err| {
+                        let interps = find_interpreter_in_sysconfig(
+                            interpreter,
+                            target,
+                            Some(*minor as usize),
+                        )
+                        .unwrap_or_default();
+                        if interps.is_empty() && !self.interpreter.is_empty() {
+                            // Print error when user supplied `--interpreter` option
+                            Err(err)
+                        } else {
+                            Ok(interps)
+                        }
+                    })?;
                     println!("🐍 Not using a specific python interpreter");
-                    if interpreter.is_empty() {
+                    if self.interpreter.is_empty() {
                         // Fake one to make `BuildContext::build_wheels` happy for abi3 when no cpython/pypy found on host
                         // The python interpreter config doesn't matter, as it's not used for anything
                         Ok(vec![PythonInterpreter {
@@ -432,9 +442,9 @@ impl BuildOptions {
                             runnable: false,
                         }])
                     } else if target.cross_compiling() {
-                        let mut interps = Vec::with_capacity(interpreters.len());
+                        let mut interps = Vec::with_capacity(found_interpreters.len());
                         let mut pypys = Vec::new();
-                        for interp in interpreters {
+                        for interp in found_interpreters {
                             if interp.interpreter_kind.is_pypy() {
                                 pypys.push(PathBuf::from(format!(
                                     "pypy{}.{}",
@@ -458,10 +468,10 @@ impl BuildOptions {
                         }
                         Ok(interps)
                     } else {
-                        if interpreters.is_empty() {
+                        if found_interpreters.is_empty() {
                             bail!("Failed to find any python interpreter");
                         }
-                        Ok(interpreters)
+                        Ok(found_interpreters)
                     }
                 }
             }

tests/common/other.rs

@@ -150,3 +150,58 @@ pub fn test_source_distribution(
     );
     Ok(())
 }
+
+pub fn abi3_python_interpreter_args() -> Result<()> {
+    // Case 1: maturin build without `-i`, should work
+    let options = BuildOptions::try_parse_from(vec![
+        "build",
+        "--manifest-path",
+        "test-crates/pyo3-pure/Cargo.toml",
+        "--quiet",
+    ])?;
+    let result = options.into_build_context(false, cfg!(feature = "faster-tests"), false);
+    assert!(result.is_ok());
+
+    // Case 2: maturin build -i python3.10, should work because python3.10 is in bundled sysconfigs
+    let options = BuildOptions::try_parse_from(vec![
+        "build",
+        "--manifest-path",
+        "test-crates/pyo3-pure/Cargo.toml",
+        "--quiet",
+        "-i",
+        "python3.10",
+    ])?;
+    let result = options.into_build_context(false, cfg!(feature = "faster-tests"), false);
+    assert!(result.is_ok());
+
+    // Windows is a bit different so we exclude it from case 3 & 4
+
+    // Case 3: maturin build -i python2.7, errors because python2.7 is supported
+    #[cfg(not(windows))]
+    {
+        let options = BuildOptions::try_parse_from(vec![
+            "build",
+            "--manifest-path",
+            "test-crates/pyo3-pure/Cargo.toml",
+            "--quiet",
+            "-i",
+            "python2.7",
+        ])?;
+        let result = options.into_build_context(false, cfg!(feature = "faster-tests"), false);
+        assert!(result.is_err());
+
+        // Case 4: maturin build -i python-does-not-exists, errors because python executable is not found
+        let options = BuildOptions::try_parse_from(vec![
+            "build",
+            "--manifest-path",
+            "test-crates/pyo3-pure/Cargo.toml",
+            "--quiet",
+            "-i",
+            "python-does-not-exists",
+        ])?;
+        let result = options.into_build_context(false, cfg!(feature = "faster-tests"), false);
+        assert!(result.is_err());
+    }
+
+    Ok(())
+}

tests/run.rs

@@ -292,3 +292,8 @@ fn workspace_with_path_dep_sdist() {
         "workspace_with_path_dep_sdist",
     ))
 }
+
+#[test]
+fn abi3_python_interpreter_args() {
+    handle_result(other::abi3_python_interpreter_args());
+}