Add a --target option to maturin list-python command

Changelog.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Fix incompatibility with cibuildwheel for 32-bit Windows in [#951](https://github.com/PyO3/maturin/pull/951)
 * Don't require `pip` error messages to be utf-8 encoding in [#953](https://github.com/PyO3/maturin/pull/953)
 * Compare minimum python version requirement between `requires-python` and bindings crate in [#954](https://github.com/PyO3/maturin/pull/954)
+* Add a `--target` option to `maturin list-python` command in [#957](https://github.com/PyO3/maturin/pull/957)
 
 ## [0.12.19] - 2022-06-05
 

src/main.rs

@@ -59,7 +59,10 @@ enum Opt {
     },
     #[clap(name = "list-python")]
     /// Searches and lists the available python installations
-    ListPython,
+    ListPython {
+        #[clap(long)]
+        target: Option<String>,
+    },
     #[clap(name = "develop")]
     /// Installs the crate as module in the current virtualenv
     ///
@@ -361,10 +364,15 @@ fn run() -> Result<()> {
 
             upload_ui(&items, &publish)?
         }
-        Opt::ListPython => {
-            let target = Target::from_target_triple(None)?;
-            // We don't know the targeted bindings yet, so we use the most lenient
-            let found = PythonInterpreter::find_all(&target, &BridgeModel::Cffi, None)?;
+        Opt::ListPython { target } => {
+            let found = if target.is_some() {
+                let target = Target::from_target_triple(target)?;
+                PythonInterpreter::find_by_target(&target)
+            } else {
+                let target = Target::from_target_triple(None)?;
+                // We don't know the targeted bindings yet, so we use the most lenient
+                PythonInterpreter::find_all(&target, &BridgeModel::Cffi, None)?
+            };
             println!("🐍 {} python interpreter found:", found.len());
             for interpreter in found {
                 println!(" - {}", interpreter);

src/python_interpreter/config.rs

@@ -85,6 +85,16 @@ impl InterpreterConfig {
         None
     }
 
+    /// Lookup wellknown sysconfigs for a given target
+    pub fn lookup_target(target: &Target) -> Vec<Self> {
+        if let Some(os_sysconfigs) = WELLKNOWN_SYSCONFIG.get(&target.target_os()) {
+            if let Some(sysconfigs) = os_sysconfigs.get(&target.target_arch()).cloned() {
+                return sysconfigs;
+            }
+        }
+        Vec::new()
+    }
+
     /// Construct a new InterpreterConfig from a pyo3 config file
     pub fn from_pyo3_config(config_file: &Path, target: &Target) -> Result<Self> {
         let config_file = fs::File::open(config_file)?;

src/python_interpreter/mod.rs

@@ -619,6 +619,14 @@ impl PythonInterpreter {
         }
     }
 
+    /// Find all available python interpreters for a given target
+    pub fn find_by_target(target: &Target) -> Vec<PythonInterpreter> {
+        InterpreterConfig::lookup_target(target)
+            .into_iter()
+            .map(Self::from_config)
+            .collect()
+    }
+
     /// Tries to find all installed python versions using the heuristic for the
     /// given platform
     pub fn find_all(