[rfc] V8 debug build CI?

[bnoordhuis]

Correct me if I'm wrong but I believe there's currently no CI job that builds V8 with all debug checks enabled?

I'm doing some local light testing in that mode and so many bugs fall out, it's not even funny (ex. #55325.) Testing that regularly would be a Very Good Thing indeed.

On a very related subject: can I suggest mirroring V8's v8_enable_debugging_features=true feature set? Right now, the configure flags one needs to use to get a build that's similar to an upstream debug build is... the words "haphazard" and "scattered" come to mind.

I know naming is hard but... ./configure --v8-non-optimized-debug? For real?!

cc @targos

[targos]

We do have a debug CI job that runs on every pull request: https://ci.nodejs.org/job/node-test-commit-arm-debug/

I don't know if ./configure --debug is "optimized" by design. Maybe it's acceptable to change the V8 flags it sets?

[targos]

@nodejs/build

[joyeecheung]

If ./configure --debug doesn't already imply v8_enable_debugging_features then IMO we should. Also the last time I checked --debug doesn't seem to make it step-debuggable on Linux, so I always ended up adding CXXFLAGS=-g, so it's probably time for --debug to get cleaned up/fixed a bit.

[joyeecheung]

I don't know if ./configure --debug is "optimized" by design. Maybe it's acceptable to change the V8 flags it sets?

My understanding is that it's similar to the is_debug setting you use for V8 GN builds (and it implies v8_enable_debugging_features in the upstream). v8_optimized_debug defaults to true in the upstream, so that's probably what --debug is also for. v8_optimized_debug = false on the other hand would make the build very slow (because it turns on a lot of slow checks) and thus is more like something you want to specifically opt into, see the PR that added --v8-non-optimized-debug #23704 - we could consider adding a daily build that uses ci.nodejs.org/job/node-test-commit-custom-suites to run the tests with a build that uses --v8-non-optimized-debug, but I would recommend against turning it on for the debug build CI that runs for every PR because it's very slow. Fixing --debug to turn on v8_enable_debugging_features in the debug CI for PRs sounds fine though.

[richardlau]

we could consider adding a daily build that uses ci.nodejs.org/job/node-test-commit-custom-suites to run the tests with a build that uses --v8-non-optimized-debug, but I would recommend against turning it on for the debug build CI that runs for every PR because it's very slow.

Part of the reason that the debug build CI we do have runs on arm64 is because those are the biggest (in terms of number of CPUs/memory) machines that we have.