Run rustfmt on Travis

[ekmartin]

This runs rustfmt with --write-mode=diff on Travis, so that the build fails if there are formatting errors. It installs rustfmt from git, with the SHA 6e41100725267974fa6dcc61134d4377b676ad01.

Also shortened a few lines that were above 100 characters, to make the build pass.

[jonhoo]

Good idea. I'm guessing we should rebase this on top of #32 to see that it actually works.

[ekmartin]

Yep! Although it did pass here earlier: https://travis-ci.org/ekmartin/distributary/builds/282452240

[jonhoo]

@ekmartin merged #32 -- rebase?

[ekmartin]

Rebased :)

[ekmartin]

Should be good to go now @jonhoo (added a commit for two more long lines: b7d7fa9)

[jonhoo]

@ekmartin why did you close this?

[ekmartin]

Woops, sorry. Deleted a bunch of branches on my fork while testing stuff with taster.

[ekmartin]

cargo fmt failed with a weird error when using the cached rustfmt binary so removed the which rustfmt || clause in e2b5649 so it reinstalls each time instead.

rustfmt: error while loading shared libraries: libsyntax-d36743e8d4fe92fe.so: cannot open shared object file: No such file or directory

[ms705]

IIRC, this happens if the Rust nightly is updated without also reinstalling rustfmt; we've had to locally do cargo install -f --git https://github.com/rust-lang-nursery/rustfmt --rev <revision> after each Rust upgrade. The reason is that rustfmt depends on a matching libsyntax from the Rust compiler.

I suspect something similar happens on Travis (e.g., they cache an old version of rustfmt).

[jonhoo]

@ms705 is right -- this is caused by a version mismatch between the compiler and rustfmt. I've cleared the travis cache, which tends to help, but it's annoying to deal with nonetheless.