From 009abf4932f7940939526ca3412a3d908394516f Mon Sep 17 00:00:00 2001
From: Matt Hillsdon <44397098+microbit-matt-hillsdon@users.noreply.github.com>
Date: Tue, 26 Sep 2023 16:48:19 +0100
Subject: [PATCH] Increase asyncify stack size (#106)

Pick the first power of two where we fail with a pystack exhausted
error in MicroPython rather than an asyncify-related error.

Add an example to the demo that finds the max stack size.
---
 src/Makefile               |  2 ++
 src/demo.html              |  1 +
 src/examples/stack_size.py | 10 ++++++++++
 3 files changed, 13 insertions(+)
 create mode 100644 src/examples/stack_size.py

diff --git a/src/Makefile b/src/Makefile
index a9f0512a..66dbdcba 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -44,6 +44,8 @@ COPT += -O3 -DNDEBUG
 endif
 
 JSFLAGS += -s ASYNCIFY
+# We can hit lower values due to user stack use. See stack_size.py example.
+JSFLAGS += -s ASYNCIFY_STACK_SIZE=262144
 JSFLAGS += -s EXIT_RUNTIME
 JSFLAGS += -s MODULARIZE=1
 JSFLAGS += -s EXPORT_NAME=createModule
diff --git a/src/demo.html b/src/demo.html
index 5889f7cf..83dabe83 100644
--- a/src/demo.html
+++ b/src/demo.html
@@ -100,6 +100,7 @@ <h1>MicroPython-micro:bit simulator example embedding</h1>
               </option>
               <option value="sound_effects_user">Sound effects (user)</option>
               <option value="speech">Speech</option>
+              <option value="stack_size">Stack size</option>
               <option value="volume">Volume</option>
             </select>
             <textarea
diff --git a/src/examples/stack_size.py b/src/examples/stack_size.py
new file mode 100644
index 00000000..4e9fae6c
--- /dev/null
+++ b/src/examples/stack_size.py
@@ -0,0 +1,10 @@
+def g():
+    global depth
+    depth += 1
+    g()
+depth = 0
+try:
+    g()
+except RuntimeError:
+    pass
+print('maximum recursion depth g():', depth)