From 9a8da93145e24666e1676120d791135d4e4eb2e5 Mon Sep 17 00:00:00 2001
From: Stephen Chung <schungx@live.com>
Date: Sat, 17 Apr 2021 18:10:57 +0800
Subject: [PATCH] Delay creation of global module until actually needed.

---
 src/engine.rs  | 10 +++++++++-
 src/fn_call.rs |  4 ----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/engine.rs b/src/engine.rs
index 8196d18d..1eaca300 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -2517,7 +2517,15 @@ impl Engine {
                 let (var_name, _alias): (Cow<'_, str>, _) = if state.is_global() {
                     #[cfg(not(feature = "no_function"))]
                     if entry_type == AccessMode::ReadOnly {
-                        let global = mods.get_mut(mods.find(KEYWORD_GLOBAL).unwrap()).unwrap();
+                        let index = if let Some(index) = mods.find(KEYWORD_GLOBAL) {
+                            index
+                        } else {
+                            // Create automatic global module
+                            mods.push(crate::engine::KEYWORD_GLOBAL, Module::new());
+                            mods.len() - 1
+                        };
+
+                        let global = mods.get_mut(index).unwrap();
                         let global = Shared::get_mut(global).unwrap();
                         global.set_var(name.clone(), value.clone());
                         global.build_index();
diff --git a/src/fn_call.rs b/src/fn_call.rs
index 3840c587..2a5c904c 100644
--- a/src/fn_call.rs
+++ b/src/fn_call.rs
@@ -826,10 +826,6 @@ impl Engine {
         lib: &[&Module],
         level: usize,
     ) -> RhaiResult {
-        // Create the global module
-        #[cfg(not(feature = "no_function"))]
-        mods.push(crate::engine::KEYWORD_GLOBAL, Module::new());
-
         self.eval_stmt_block(scope, mods, state, lib, &mut None, statements, false, level)
             .or_else(|err| match *err {
                 EvalAltResult::Return(out, _) => Ok(out),