getpath

RustPython · youknowone · Dec 20, 2025 · Dec 20, 2025 · Dec 20, 2025 · Dec 20, 2025
commit cc98ba60664a99cf70ad4bc2ca524a46171db3bb
diff --git a/crates/vm/src/getpath.rs b/crates/vm/src/getpath.rs
@@ -0,0 +1,237 @@
+//! Path configuration for RustPython (ref: Modules/getpath.py)
+//!
+//! This module provides path calculation logic but implemented directly in Rust.
+//!
+//! The main entry point is `init_path_config()` which should be called
+//! before interpreter initialization to populate Settings with path info.
+
+use std::env;
+use std::path::{Path, PathBuf};
+
+use crate::version;
+use crate::vm::Settings;
+
+/// Initialize path configuration in Settings (like getpath.py)
+///
+/// This function should be called before interpreter initialization.
+/// It computes executable, base_executable, prefix, and module_search_paths.
+pub fn init_path_config(settings: &mut Settings) {
+    // Skip if already configured
+    if settings.module_search_paths_set {
+        return;
+    }
+
+    // 1. Compute executable path
+    if settings.executable.is_none() {
+        settings.executable = get_executable_path().map(|p| p.to_string_lossy().into_owned());
+    }
+
+    let exe_path = settings
+        .executable
+        .as_ref()
+        .map(PathBuf::from)
+        .or_else(get_executable_path);
+
+    // 2. Compute base_executable (for venv support)
+    if settings.base_executable.is_none() {
+        settings.base_executable = compute_base_executable(exe_path.as_deref());
+    }
+
+    // 3. Compute prefix paths (with fallbacks to ensure all values are set)
+    let (prefix, base_prefix) = compute_prefixes(exe_path.as_deref());
+    let default_prefix = || {
+        std::option_env!("RUSTPYTHON_PREFIX")
+            .map(String::from)
+            .unwrap_or_else(|| if cfg!(windows) { "C:" } else { "/usr/local" }.to_owned())
+    };
+
+    if settings.prefix.is_none() {
+        settings.prefix = Some(prefix.clone().unwrap_or_else(default_prefix));
+    }
+    if settings.base_prefix.is_none() {
+        settings.base_prefix = Some(
+            base_prefix
+                .clone()
+                .or_else(|| prefix.clone())
+                .unwrap_or_else(default_prefix),
+        );
+    }
+    if settings.exec_prefix.is_none() {
+        settings.exec_prefix = settings.prefix.clone();
+    }
+    if settings.base_exec_prefix.is_none() {
+        settings.base_exec_prefix = settings.base_prefix.clone();
+    }
+
+    // 4. Build module_search_paths (use settings.base_prefix which is now guaranteed to be set)
+    settings.module_search_paths =
+        compute_module_search_paths(settings, settings.base_prefix.as_deref());
+    settings.module_search_paths_set = true;
+}
+
+/// Compute base_executable from executable path
+fn compute_base_executable(exe_path: Option<&Path>) -> Option<String> {
+    let exe_path = exe_path?;
+
+    // Check for __PYVENV_LAUNCHER__ environment variable (like getpath.c env_to_dict)
+    if let Ok(launcher) = env::var("__PYVENV_LAUNCHER__") {
+        return Some(launcher);
+    }
+
+    // Check if we're in a venv
+    if let Some(venv_home) = get_venv_home(exe_path) {
+        // venv_home is the bin directory containing the base Python
+        let home_path = PathBuf::from(&venv_home);
+        let exe_name = exe_path.file_name()?;
+        let base_exe = home_path.join(exe_name);
+        if base_exe.exists() {
+            return Some(base_exe.to_string_lossy().into_owned());
+        }
+        // Fallback: just return the home directory path with exe name
+        return Some(base_exe.to_string_lossy().into_owned());
+    }
+
+    // Not in venv: base_executable == executable
+    Some(exe_path.to_string_lossy().into_owned())
+}
+
+/// Compute prefix and base_prefix from executable path
+fn compute_prefixes(exe_path: Option<&Path>) -> (Option<String>, Option<String>) {
+    let Some(exe_path) = exe_path else {
+        return (None, None);
+    };
+
+    let exe_dir = match exe_path.parent() {
+        Some(d) => d,
+        None => return (None, None),
+    };
+
+    // Check if we're in a venv
+    if let Some(venv_home) = get_venv_home(exe_path) {
+        // prefix is the venv directory (parent of bin/)
+        let prefix = exe_dir.parent().map(|p| p.to_string_lossy().into_owned());
+
+        // base_prefix is parent of venv_home (the original Python's prefix)
+        let home_path = PathBuf::from(&venv_home);
+        let base_prefix = home_path.parent().map(|p| p.to_string_lossy().into_owned());
+
+        return (prefix, base_prefix);
+    }
+
+    // Not in venv: prefix == base_prefix
+    let prefix = exe_dir.parent().map(|p| p.to_string_lossy().into_owned());
+    (prefix.clone(), prefix)
+}
+
+/// Build the complete module_search_paths (sys.path)
+fn compute_module_search_paths(settings: &Settings, base_prefix: Option<&str>) -> Vec<String> {
+    let mut paths = Vec::new();
+
+    // 1. Add paths from path_list (PYTHONPATH/RUSTPYTHONPATH)
+    paths.extend(settings.path_list.iter().cloned());
+
+    // 2. Add zip stdlib path
+    if let Some(base_prefix) = base_prefix {
+        let platlibdir = "lib";
+        let zip_name = format!("rustpython{}{}", version::MAJOR, version::MINOR);
+        let zip_path = PathBuf::from(base_prefix).join(platlibdir).join(&zip_name);
+        paths.push(zip_path.to_string_lossy().into_owned());
+    }
+
+    paths
+}
+
+/// Get the zip stdlib path to add to sys.path
+///
+/// Returns a path like `/usr/local/lib/rustpython313` or
+/// `/path/to/venv/lib/rustpython313` for virtual environments.
+pub fn get_zip_stdlib_path() -> Option<String> {
+    // ZIP_LANDMARK pattern: {platlibdir}/{impl_name}{VERSION_MAJOR}{VERSION_MINOR}
+    let platlibdir = "lib";
+    let zip_name = format!("rustpython{}{}", version::MAJOR, version::MINOR);
+
+    let base_prefix = get_base_prefix()?;
+    let zip_path = base_prefix.join(platlibdir).join(&zip_name);
+
+    Some(zip_path.to_string_lossy().into_owned())
+}
+
+/// Get the base prefix directory
+///
+/// For installed Python: parent of the bin directory
+/// For venv: the 'home' value from pyvenv.cfg
+fn get_base_prefix() -> Option<PathBuf> {
+    let exe_path = get_executable_path()?;
+    let exe_dir = exe_path.parent()?;
+
+    // Check if we're in a venv by looking for pyvenv.cfg
+    if let Some(venv_home) = get_venv_home(&exe_path) {
+        // venv_home is the directory containing the base Python
+        // Go up one level to get the prefix (e.g., /usr/local from /usr/local/bin)
+        let home_path = PathBuf::from(&venv_home);
+        if let Some(parent) = home_path.parent() {
+            return Some(parent.to_path_buf());
+        }
+        return Some(home_path);
+    }
+
+    // Not in venv: go up from bin/ to get prefix
+    // e.g., /usr/local/bin/rustpython -> /usr/local
+    exe_dir.parent().map(|p| p.to_path_buf())
+}
+
+/// Get the current executable path
+fn get_executable_path() -> Option<PathBuf> {
+    #[cfg(not(target_arch = "wasm32"))]
+    {
+        let exec_arg = env::args_os().next()?;
+        which::which(exec_arg).ok()
+    }
+    #[cfg(target_arch = "wasm32")]
+    {
+        let exec_arg = env::args().next()?;
+        Some(PathBuf::from(exec_arg))
+    }
+}
+
+/// Get the 'home' value from pyvenv.cfg if running in a virtual environment
+///
+/// pyvenv.cfg is located in the parent directory of the bin directory
+/// (e.g., venv/pyvenv.cfg when executable is venv/bin/rustpython)
+pub fn get_venv_home(exe_path: &Path) -> Option<String> {
+    let exe_dir = exe_path.parent()?;
+    let venv_dir = exe_dir.parent()?;
+    let pyvenv_cfg = venv_dir.join("pyvenv.cfg");
+
+    if !pyvenv_cfg.exists() {
+        return None;
+    }
+
+    parse_pyvenv_home(&pyvenv_cfg)
+}
+
+/// Parse pyvenv.cfg and extract the 'home' key value
+fn parse_pyvenv_home(pyvenv_cfg: &Path) -> Option<String> {
+    let content = std::fs::read_to_string(pyvenv_cfg).ok()?;
+
+    for line in content.lines() {
+        if let Some((key, value)) = line.split_once('=')
+            && key.trim().to_lowercase() == "home"
+        {
+            return Some(value.trim().to_string());
+        }
+    }
+
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_zip_stdlib_path_format() {
+        // Just verify it returns something and doesn't panic
+        let _path = get_zip_stdlib_path();
+    }
+}
diff --git a/crates/vm/src/lib.rs b/crates/vm/src/lib.rs
@@ -60,6 +60,7 @@ pub mod exceptions;
 pub mod format;
 pub mod frame;
 pub mod function;
+pub mod getpath;
 pub mod import;
 mod intern;
 pub mod iter;