EMSDK 1.39.7 broken in a recent release of the tools

[janjongboom]

Hi @kripken, not sure if this is something you want to address, but we're using EMSDK 1.39.7 in some of our build pipelines. We run this in a container, basically via:

$ git clone https://github.com/emscripten-core/emsdk.git && \
    cd emsdk && \
    ./emsdk install 1.39.7 && \
    ./emsdk activate 1.39.7

$ echo "PATH=$PATH:/app/emsdk:/app/emsdk/node/12.9.1_64bit/bin:/app/emsdk/upstream/emscripten" > ~/.bashrc

This worked fine up until yesterday (this could have been broken earlier, but yesterday a rebuild of this container was triggered), but now fails with:

#16 0.631 shared:ERROR: BINARYEN_ROOT is set to empty value in /root/.emscripten

Naturally fixed quickly on our end by checking out the 1.39.7 tag for EMSDK, but FYI.

[kripken]

Interesting, I'm not sure what could cause that. I don't think we've done any changes to how BINARYEN_ROOT is set up, did we @sbc100 ?

One possibility is that @sbc100 made the .emscripten file be emitted in the emsdk directory by default, instead of the home dir. Perhaps there was an older file in one of the two locations?

When it gives that error, what are the full contents of your .emscripten file?

[sbc100]

Ah yes. the change that broke this use case I believe is that one that made --embedded the default: #472

Really you are supposed to run source ./emsdk_env.sh to ensure not just PATH but other environment variables such as EM_CONFIG got set correctly. However, it turns that that it was possible in that past to just set PATH alone and it would be enough (since emscripten would find the $HOME/.emscripten file on its own by default).

With newer version of emscripten this also works fine since they will try to look two levels up and so will also find the embedded config by default. Older version of emscripten require EM_CONFIG to be set to find the embedded config.

There are several solutions that I can offer here:

1. Use source ./emsdk_env.sh in your bash shell. This is technically the correct way to configure the emsdk which is why this is my number one suggestion :)
2. Pass --no-embedded to emsdk activate (not recommended as I hope to remove this option at some point but will work until that point).
3. Set EM_CONFIG=/path/to/emsdk/.emscripten as well as adding to your PATH (this emulates part of what emsdk_env would do).
4. Upgrade to a more recent version of the sdk (probably not easy otherwise you would already have done it)