runtime_debug/checkInt overly aggressive when ASSERTIONS=2

[RosHartigan]

When I run my emscripten app for debugging after compiling it with ASSERTIONS=2, the app aborts after calling stat, and after calling fillMouseEventData.

• In stat, the stat.rdev instance member is 'undefined', which causes an abort. (library_workerfs.js:85)
• In fillMouseEventData, 'e.clientX - rect.left' resolves to a float, not an int, which also causes an abort. (library_html5.js:439)

I believe this pull request is the breaking change for me: #19251

I've reverted to ASSERTIONS=1, but I'd love to debug with a higher assertion level.

Console output
t RuntimeError: Aborted(Assertion failed: attempt to write non-integer (undefined) into integer heap)
at abort (cskyclasses-debug.js:836:10)
at assert (cskyclasses-debug.js:615:3)
at checkInt (cskyclasses-debug.js:1074:2)
at checkInt32 (cskyclasses-debug.js:1085:27)
at setValue_safe (cskyclasses-debug.js:5460:3)
at SAFE_HEAP_STORE (cskyclasses-debug.js:564:2)
at Object.doStat (cskyclasses-debug.js:4697:3)
at ___syscall_stat64 (cskyclasses-debug.js:5807:19)
at fstatat (fstatat.c:148:9)
at stat (stat.c:6:9)

Version of emscripten/emsdk:
emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.1.41 (71634e0)
clang version 17.0.0 (https://github.com/llvm/llvm-project 88421ea973916e60c34beb26597a5fc33f83dd8f)
Target: wasm32-unknown-emscripten
Thread model: posix

Full link command and output with -v appended:
Output of link is attached.
ssww_emcc_link_log_2023-06-19.txt

[sbc100]

For the rdev issues I have uploaded #19657.. for the fillMouseEventData issue, do you know why e.clientX - rect.left results in a floating point value? I would have through those would be measures in pixels and be integers... but I'm not an export on these things. Can you share the values that e.clientX and rect.left have?

[RosHartigan]

Thanks for responding!

rect is a DOMRect with members that can be floating point, e is the event structure with int members.

rect: DOMRect {x: 175.1953125, y: 0, width: 1701, height: 410, top: 0, …}
e: MouseEvent {isTrusted: true, screenX: 689, screenY: 475, clientX: 414, clientY: 368, …}

[sbc100]

I think we should probably explicit round the DOMRect values to the nearest integer.

[RosHartigan]

That seems like the best solution, given that all the other coordinates are integer.