In CI check that the snapshots have been checked in.

[cristianoc]

Fail CI otherwise. CC @cknitt

E.g. current CI is not clean.

[cristianoc]

Example: https://github.com/rescript-lang/rescript-compiler/pull/5399

[cristianoc]

Again: https://github.com/rescript-lang/rescript-compiler/pull/5408

[cknitt]

I think for now this is good idea to avoid inconsistencies, but for the longer term, we should investigate whether we can avoid checking in those snapshots with every change, as they are of significant size:

du -sch lib/4.06.1/**/*compiler*.ml
 12M    lib/4.06.1/unstable/js_compiler.ml
 13M    lib/4.06.1/unstable/js_playground_compiler.ml
 13M    lib/4.06.1/whole_compiler.ml
 38M    total

[cknitt]

Unfortunately my tests so far have shown that the build of the above files is non-deterministic, i.e., the output is different on every build. 😞

Therefore, I only made a PR to check whether lib/js and lib/es6 are up to date: #5435.

[cknitt]

Closing as there are no snapshots anymore. 🎉