Make if work like a def-env

crates/nu-command/src/core_commands/if_.rs

@@ -37,50 +37,88 @@ impl Command for If {
  fn run(
  &self,
  engine_state: &EngineState,
- stack: &mut Stack,
+ caller_stack: &mut Stack,
  call: &Call,
  input: PipelineData,
  ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
  let cond = &call.positional[0];
- let then_block: CaptureBlock = call.req(engine_state, stack, 1)?;
+ let then_block: CaptureBlock = call.req(engine_state, caller_stack, 1)?;
  let else_case = call.positional.get(2);
 
- let result = eval_expression(engine_state, stack, cond)?;
+ let result = eval_expression(engine_state, caller_stack, cond)?;
  match &result {
  Value::Bool { val, .. } => {
  if *val {
  let block = engine_state.get_block(then_block.block_id);
- let mut stack = stack.captures_to_stack(&then_block.captures);
- eval_block(
+ let mut callee_stack = caller_stack.captures_to_stack(&then_block.captures);
+ let result = eval_block(
  engine_state,
- &mut stack,
+ &mut callee_stack,
  block,
  input,
  call.redirect_stdout,
  call.redirect_stderr,
- )
+ );
+ let caller_env_vars = caller_stack.get_env_var_names(engine_state);
+
+ // remove env vars that are present in the caller but not in the callee
+ // (the callee hid them)
+ for var in caller_env_vars.iter() {
+ if !callee_stack.has_env_var(engine_state, var) {
+ caller_stack.remove_env_var(engine_state, var);
+ }
+ }
+
+ // add new env vars from callee to caller
+ for env_vars in callee_stack.env_vars {
+ for (var, value) in env_vars {
+ caller_stack.add_env_var(var, value);
+ }
+ }
+
+ result
  } else if let Some(else_case) = else_case {
  if let Some(else_expr) = else_case.as_keyword() {
  if let Some(block_id) = else_expr.as_block() {
- let result = eval_expression(engine_state, stack, else_expr)?;
+ let result = eval_expression(engine_state, caller_stack, else_expr)?;
  let else_block: CaptureBlock = FromValue::from_value(&result)?;
 
- let mut stack = stack.captures_to_stack(&else_block.captures);
+ let mut callee_stack =
+ caller_stack.captures_to_stack(&else_block.captures);
  let block = engine_state.get_block(block_id);
- eval_block(
+ let result = eval_block(
  engine_state,
- &mut stack,
+ &mut callee_stack,
  block,
  input,
  call.redirect_stdout,
  call.redirect_stderr,
- )
+ );
+
+ let caller_env_vars = caller_stack.get_env_var_names(engine_state);
+
+ // remove env vars that are present in the caller but not in the callee
+ // (the callee hid them)
+ for var in caller_env_vars.iter() {
+ if !callee_stack.has_env_var(engine_state, var) {
+ caller_stack.remove_env_var(engine_state, var);
+ }
+ }
+
+ // add new env vars from callee to caller
+ for env_vars in callee_stack.env_vars {
+ for (var, value) in env_vars {
+ caller_stack.add_env_var(var, value);
+ }
+ }
+
+ result
  } else {
- eval_expression(engine_state, stack, else_expr)
+ eval_expression(engine_state, caller_stack, else_expr)
  .map(|x| x.into_pipeline_data())
  }
  } else {
- eval_expression(engine_state, stack, else_case)
+ eval_expression(engine_state, caller_stack, else_case)
  .map(|x| x.into_pipeline_data())
  }
  } else {