Address review: tighten max_call_depth on MSVC Debug

Windows MSVC Debug builds crashed unit.recursion_depth_protection.chai
with SEGFAULT before the depth check could fire. Windows defaults to a
1 MiB thread stack and Debug builds emit much larger per-frame native
stack usage (no inlining, /RTC, buffer security checks), so 256 nested
ChaiScript calls overflow the native stack long before the dispatcher
reaches max_call_depth. Linux/macOS and MSVC Release pass at 256.

Pick a tighter default (32) only for the MSVC + _DEBUG configuration
that needs it, leaving every other build at the original 256, and shrink
the count_down recursion in the regression test so the bounded path
stays well below every platform's default.

Requested by @lefticus in PR #700 review.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
leftibot 2026-04-30 16:54:56 -06:00
parent 5cf5049549
commit ec05fcf3d4
2 changed files with 14 additions and 2 deletions

View File

@ -79,9 +79,19 @@ static_assert(_MSC_FULL_VER >= 190024210, "Visual C++ 2015 Update 3 or later req
// causes the dispatcher to throw chaiscript::exception::stack_overflow_error
// instead of letting the native call stack overflow. Defining the macro on
// the command line overrides the default.
//
// MSVC Debug builds emit very large per-frame native stack usage (no inlining,
// /RTC, buffer security checks) and Windows defaults to a 1 MiB thread stack,
// so the same ChaiScript depth that fits comfortably on Linux/macOS or in an
// MSVC Release build overflows the native stack before the depth check fires.
// We pick a tighter default in that configuration to keep the throw reachable.
#ifndef CHAISCRIPT_MAX_CALL_DEPTH
#if defined(CHAISCRIPT_MSVC) && defined(_DEBUG)
#define CHAISCRIPT_MAX_CALL_DEPTH 32
#else
#define CHAISCRIPT_MAX_CALL_DEPTH 256
#endif
#endif
#include <cmath>
#include <memory>

View File

@ -30,10 +30,12 @@ assert_true(caught)
// distinguish it from an arbitrary script-level error.
assert_true(find(message, "call stack") != -1)
// A bounded recursion that stays below the limit must keep working.
// A bounded recursion that stays well below the limit must keep working.
// Use a small depth so the test passes on every platform default - notably
// the MSVC Debug build where the native stack budget forces a tighter cap.
def count_down(n) {
if (n <= 0) { return 0 }
return count_down(n - 1) + 1
}
assert_equal(50, count_down(50))
assert_equal(10, count_down(10))