Automatically create RYE_HOME in config

rye/src/config.rs

@@ -55,6 +55,10 @@ impl Config {
 
     /// Saves changes back.
     pub fn save(&self) -> Result<(), Error> {
+        // try to make the parent folder if it does not exist.  ignore the error though.
+        if let Some(parent) = self.path.parent() {
+            fs::create_dir_all(parent).ok();
+        }
         fs::write(&self.path, self.doc.to_string())
             .path_context(&self.path, "failed to save config")?;
         Ok(())

rye/tests/test_config.rs

@@ -1,3 +1,7 @@
+use std::fs;
+
+use insta::assert_snapshot;
+
 use crate::common::{rye_cmd_snapshot, Space};
 
 mod common;
@@ -109,3 +113,24 @@ fn test_config_show_path_and_any_action() {
     error: an argument cannot be used with one or more of the other specified arguments
     "###);
 }
+
+#[test]
+fn test_config_save_missing_folder() {
+    let space = Space::new();
+    let fake_home = space.project_path().join("missing-thing");
+    rye_cmd_snapshot!(space.rye_cmd()
+        .arg("config")
+        .arg("--set")
+        .arg("default.toolchain=cpython@3.12")
+        .env("RYE_HOME", fake_home.as_os_str()), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    "###);
+    assert_snapshot!(fs::read_to_string(fake_home.join("config.toml")).unwrap(), @r###"
+    [default]
+    toolchain = "cpython@3.12"
+    "###);
+}