Update submodules while running build.sh, and make it runs well

[TheKK]

No description provided.

[kripken]

I actually don't know git submodules that well - what do those commands do? I wouldn't want them to pull new changes from those repos, as I need to pull them manually and fix things when they break.

[jcbeyler]

Agreed, I do that manually to keep the HEAD sane. Doing it at build time is really an invitation to having issues for the user / testers / etc.

[jcbeyler]

Plus bug reports would become really annoying since each user might have a different configuration depending on what is happening in the submodules compared to what you have or will have by the time you test...

[binji]

None of those commands pull new changes, see https://git-scm.com/docs/git-submodule.

[jcbeyler]

True I read way too fast the code. The pull command would be adding new updates :)

[TheKK]

git submodule update won't checkout the latest commit for submodules, but stay at the commit when you add it as submodule unless you manually checkout to different commit in submodules then commit changes in binaryen.

Perhapse updating submodule in build.sh is not the best idea. But since files from these submodules are needed while running check.py, I think we should tell others to download them or help them with that.

[kripken]

I see, thanks. How about creating an update.sh that does this? And perhaps warn from check.py if those directories are not created/up to date?

On the other hand, keeping it in build.sh as currently done in this pull is nice for simplicity, it would just work for most people. I guess I don't feel strongly either way.

[jcbeyler]

Actually you could put an option to build.sh that does the update or not and then test for that option. At least that way you don' t have to have two different scripts, no?

It' s mostly a build time question. Every time you build you will have to wait for git to finish checking the submodules. So depending on how often you are building, you may or not start caring about this

[TheKK]

As I know binaryen is now seeking for new build system, does that means build.sh will gone in the future? If so, maybe we could just put submodule update instruction to README, otherwise adding an option to build.sh sounds nice.

[kripken]

Yeah, we need a proper build system anyhow, so build.sh will be going away, I hope ;)

So I'm ok to merge this as-is. Although, the idea of putting the info in the README instead sounds better actually.

[kripken]

Thinking some more, let's do both, I'll merge this and add it to the readme.