fix: prepend virtualenv path rather than append (#1751)

prepend all virtualenv PATHs so the most nested directory is at the
front of the vector.

otherwise the most globally configured virtualenv takes precedence

add unit tests and e2e tests to verify this change

e2e/test_python

@@ -19,6 +19,23 @@ assert_contains "mise x [email protected] -- python --version" "Python 3.12.0"
 assert_contains "mise env -s bash | grep VIRTUAL_ENV" "$MISE_DATA_DIR/venv"
 assert "mise x -- which python" "$MISE_DATA_DIR/venv/bin/python"
 
+# verify nested virtualenv is used
+mkdir -p subdir
+cat >subdir/.e2e.mise.toml <<EOF
+[env._.python]
+venv = {path = "{{env.MISE_DATA_DIR}}/subvenv", create=true}
+[tools]
+python = "{{exec(command='echo 3.12.0')}}"
+EOF
+
+cd subdir
+mise i
+assert_contains "mise x [email protected] -- python --version" "Python 3.12.0"
+assert_contains "mise env -s bash | grep VIRTUAL_ENV" "$MISE_DATA_DIR/subvenv"
+assert "mise x -- which python" "$MISE_DATA_DIR/subvenv/bin/python"
+
+rm -rf subdir
+
 if [ "${TEST_ALL:-}" != 1 ]; then
 	exit
 fi

src/config/env_directive.rs

@@ -191,7 +191,7 @@ impl EnvResults {
                         }
                     }
                     if venv.exists() {
-                        r.env_paths.push(venv.join("bin"));
+                        r.env_paths.insert(0, venv.join("bin"));
                         env.insert(
                             "VIRTUAL_ENV".into(),
                             (venv.to_string_lossy().to_string(), Some(source.clone())),
@@ -279,4 +279,39 @@ mod tests {
         "###
         );
     }
+
+    #[test]
+    fn test_venv_path() {
+        let env = HashMap::new();
+        let results = EnvResults::resolve(
+            &env,
+            vec![
+                (
+                    EnvDirective::PythonVenv {
+                        path: PathBuf::from("/"),
+                        create: false,
+                    },
+                    Default::default(),
+                ),
+                (
+                    EnvDirective::PythonVenv {
+                        path: PathBuf::from("./"),
+                        create: false,
+                    },
+                    Default::default(),
+                ),
+            ],
+        )
+        .unwrap();
+        // expect order to be reversed as it processes directives from global to dir specific
+        assert_debug_snapshot!(
+            results.env_paths.into_iter().map(|p| replace_path(&p.display().to_string())).collect::<Vec<_>>(),
+            @r###"
+        [
+            "~/cwd/bin",
+            "/bin",
+        ]
+        "###
+        );
+    }
 }