CPPIA JIT: typed-array helper exceptions bypass script catches and terminate the host #404

CPPIA's JIT terminates the host when these typed-array operations throw, even when the script wraps the operation in try/catch:

• cpp.NativeArray.blit(dest, -1, source, 0, 1) with two-element Int arrays.
• cpp.NativeArray.setSize(values, -1) with a two-element Int array.
• values.resize(0x40000000) with an Int array. The runtime rejects the element count before allocating the buffer.

The same script catches all three exceptions and continues under the interpreter and native C++. A mixed Array<Dynamic> blit with an invalid source range also recovers under both CPPIA engines in this test.

Minimal example:

var values = [7, 8];
try {
    cpp.NativeArray.setSize(values, -1);
} catch (e:Dynamic) {
    Sys.println("caught");
}
Sys.println("continued");

Expected: the script catches the exception and continues with the original array intact.

Observed on Windows x64: the JIT child exits with -529697949 (0xE06D7363, an unhandled C++ exception). Neither the script catch nor the host catch around Host.runFile runs.

src/hx/cppia/ArrayBuiltin.cpp calls runBlit, runSetSizeExact and runResize directly from generated code. These helpers do not use TRY_NATIVE / CATCH_NATIVE, and their call sites do not check the pending exception. Helpers such as runSort and runToString already use that exception bridge.

Added the conventional local regression fixture test/regression/CppiaBlitException/{Script.hx,Main.hx,build.hxml,stdout.txt} before reporting. It runs each engine and operation in a separate child, checks array contents after the catch, and includes a valid blit and the dynamic-array control. No runtime fix is included. The fixture is local and has not been committed.

Validation on 4cdca96, Haxe 4.3.7, MSVC 19.44, Windows x64 release:

The fix belongs in libhxcpp's JIT/native exception bridge and does not require a compiler or stdlib change. This is separate from #66, which concerned script exceptions returning to native callers.