From d511aac7a4c42ee824a0054fa3f83bf79922fd59 Mon Sep 17 00:00:00 2001
From: Stephen Chung <Stephen.Chung@intexact.com>
Date: Thu, 8 Oct 2020 23:00:01 +0800
Subject: [PATCH] Reduce max call stack size for debug.

---
 RELEASES.md                      | 1 +
 doc/src/safety/max-call-stack.md | 6 +++---
 src/engine.rs                    | 2 +-
 tests/optimizer.rs               | 2 +-
 tests/stack.rs                   | 4 ++--
 5 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/RELEASES.md b/RELEASES.md
index a3124b96..038d3b2a 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -26,6 +26,7 @@ Enhancements
 ------------
 
 * Many one-liners and few-liners are now marked `#[inline]` or `[inline(always)]`, just in case it helps when LTO is not turned on.
+* Default call stack depth for `debug` builds is reduced to 12 (from 16).
 
 
 Version 0.19.0
diff --git a/doc/src/safety/max-call-stack.md b/doc/src/safety/max-call-stack.md
index 2d33d653..374dc2a6 100644
--- a/doc/src/safety/max-call-stack.md
+++ b/doc/src/safety/max-call-stack.md
@@ -6,7 +6,7 @@ Maximum Call Stack Depth
 Limit How Stack Usage by Scripts
 -------------------------------
 
-Rhai by default limits function calls to a maximum depth of 128 levels (16 levels in debug build).
+Rhai by default limits function calls to a maximum depth of 128 levels (12 levels in debug build).
 
 This limit may be changed via the `Engine::set_max_call_levels` method.
 
@@ -17,9 +17,9 @@ This check can be disabled via the [`unchecked`] feature for higher performance
 ```rust
 let mut engine = Engine::new();
 
-engine.set_max_call_levels(10); // allow only up to 10 levels of function calls
+engine.set_max_call_levels(10);     // allow only up to 10 levels of function calls
 
-engine.set_max_call_levels(0);  // allow no function calls at all (max depth = zero)
+engine.set_max_call_levels(0);      // allow no function calls at all (max depth = zero)
 ```
 
 
diff --git a/src/engine.rs b/src/engine.rs
index 9708f365..156551a9 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -75,7 +75,7 @@ pub type Imports = Vec<(ImmutableString, Module)>;
 
 #[cfg(not(feature = "unchecked"))]
 #[cfg(debug_assertions)]
-pub const MAX_CALL_STACK_DEPTH: usize = 16;
+pub const MAX_CALL_STACK_DEPTH: usize = 12;
 #[cfg(not(feature = "unchecked"))]
 #[cfg(debug_assertions)]
 pub const MAX_EXPR_DEPTH: usize = 32;
diff --git a/tests/optimizer.rs b/tests/optimizer.rs
index da224262..4e66552c 100644
--- a/tests/optimizer.rs
+++ b/tests/optimizer.rs
@@ -1,6 +1,6 @@
 #![cfg(not(feature = "no_optimize"))]
 
-use rhai::{Engine, EvalAltResult, OptimizationLevel, INT, RegisterFn};
+use rhai::{Engine, EvalAltResult, OptimizationLevel, RegisterFn, INT};
 
 #[test]
 fn test_optimizer_run() -> Result<(), Box<EvalAltResult>> {
diff --git a/tests/stack.rs b/tests/stack.rs
index b7ff9a57..03edee0e 100644
--- a/tests/stack.rs
+++ b/tests/stack.rs
@@ -10,10 +10,10 @@ fn test_stack_overflow_fn_calls() -> Result<(), Box<EvalAltResult>> {
         engine.eval::<INT>(
             r"
                 fn foo(n) { if n <= 1 { 0 } else { n + foo(n-1) } }
-                foo(8)
+                foo(7)
     ",
         )?,
-        35
+        27
     );
 
     #[cfg(not(feature = "unchecked"))]