Merge stack before printing (#9304)

Could you @fdncred try it?

close?: #9264

---------

Signed-off-by: Maxim Zhiburt <zhiburt@gmail.com>
Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>

crates/nu-protocol/src/engine/engine_state.rs

@@ -279,11 +279,7 @@ impl EngineState {
     }
 
     /// Merge the environment from the runtime Stack into the engine state
-    pub fn merge_env(
-        &mut self,
-        stack: &mut Stack,
-        cwd: impl AsRef<Path>,
-    ) -> Result<(), ShellError> {
+    pub fn merge_env(&mut self, stack: &mut Stack) -> Result<(), ShellError> {
         for mut scope in stack.env_vars.drain(..) {
             for (overlay_name, mut env) in scope.drain() {
                 if let Some(env_vars) = self.env_vars.get_mut(&overlay_name) {
@@ -310,12 +306,27 @@ impl EngineState {
             }
         }
 
+        Ok(())
+    }
+
+    /// Set a CWD.
+    pub fn set_current_working_dir(&mut self, cwd: impl AsRef<Path>) -> Result<(), ShellError> {
         // TODO: better error
         std::env::set_current_dir(cwd)?;
-
         Ok(())
     }
 
+    /// Merge the environment from the runtime Stack into the engine state
+    ///
+    /// A merge which does not consume the stack env.
+    pub fn clone_with_env(&self, stack: &Stack) -> Result<Self, ShellError> {
+        let mut engine = self.clone();
+        let mut stack = stack.clone();
+        engine.merge_env(&mut stack)?;
+
+        Ok(engine)
+    }
+
     /// Mark a starting point if it is a script (e.g., nu spam.nu)
     pub fn start_in_file(&mut self, file_path: Option<&str>) {
         self.currently_parsed_cwd = if let Some(path) = file_path {