feat: add mise_env tera variable for templates

docs/templates.md

@@ -128,6 +128,7 @@ These variables offer key information about the current environment:
 - `config_root: PathBuf` – Locates the directory containing your `mise.toml` file, or in the case of something like `~/src/myproj/.config/mise.toml`, it will point to `~/src/myproj`.
 - `mise_bin: String` - Points to the path to the current mise executable
 - `mise_pid: String` - Points to the pid of the current mise process
+- `mise_env: String` - The configuration environment as specified by `MISE_ENV`, `-E`, or `--env`. Will be undefined if the configuration environment is not set.
 - `xdg_cache_home: PathBuf` - Points to the directory of XDG cache home
 - `xdg_config_home: PathBuf` - Points to the directory of XDG config home
 - `xdg_data_home: PathBuf` - Points to the directory of XDG data home

e2e/env/test_env_profiles

@@ -7,3 +7,13 @@ echo 'env.AAA = "override-2"' >mise.override2.toml
 assert "mise env --json | jq -r .AAA" "main"
 MISE_ENV=override1 assert "mise env --json | jq -r .AAA" "override-1"
 MISE_ENV=override1,override2 assert "mise env --json | jq -r .AAA" "override-2"
+
+cat <<EOF >mise.toml
+[tasks.print]
+run = '{% if mise_env %}echo {{mise_env}}{% endif %}'
+EOF
+assert "mise run print" ""
+MISE_ENV=env1 assert "mise run print" "[env1]"
+MISE_ENV=env1,env2 assert "mise run print" "[env1, env2]"
+assert "mise --env env3 run print" "[env3]"
+assert "mise -E env3,env4 run print" "[env3, env4]"

src/tera.rs

@@ -22,6 +22,9 @@ pub static BASE_CONTEXT: Lazy<Context> = Lazy::new(|| {
     context.insert("env", &*env::PRISTINE_ENV);
     context.insert("mise_bin", &*env::MISE_BIN);
     context.insert("mise_pid", &*env::MISE_PID);
+    if !(*env::MISE_ENV).is_empty() {
+        context.insert("mise_env", &*env::MISE_ENV);
+    }
     if let Ok(dir) = env::current_dir() {
         context.insert("cwd", &dir);
     }
@@ -381,6 +384,11 @@ mod tests {
         assert_eq!(render("{{config_root}}"), "/");
     }
 
+    #[test]
+    fn test_mise_env() {
+        assert_eq!(render("{% if mise_env %}{{mise_env}}{% endif %}"), "");
+    }
+
     #[test]
     fn test_cwd() {
         assert_eq!(render("{{cwd}}"), "/");