cargo recursive install is broken

[erickt]

Here's an example:

% cargo install mongrel2
info: syncing source: central...
info: synced source: central
info: installing central/mongrel2 via git...
info: installing central/zmq via git...
rust: task failed at 'Assertion task::local_data::local_data_get(cast::transmute::<(uint, uint),
                                                   &
                                                   fn&
                                                       (+v:
                                                            @@token::ident_interner)>((-3
                                                                                           as
                                                                                           uint,
                                                                                       0u))).is_none() failed', /Users/etryzelaar/Projects/rust/rust/src/libsyntax/parse/token.rs:362

[erickt]

I'm going to vote for this to be a 0.4 blocker since it's breaking cargos like rust-mongrel2.

Cargo is violating an assumption in the parser that there's only one parser made per task. syntax::parse::new_parse_sess calls syntax::parse::token::mk_ident_interner, which caches an interner in TLS on the first call, or assert if an interner has already been created. Unfortunately cargo creates a new parser session per crate, which triggers the assertion.

I think this won't be too hard to work around. We could just get rid of the assertion, and share the interner across all parsers in the same thread. I'll prep a patch for this. I'm not sure if this will violate other assumptions in the compiler though.

The other option would be to hack up cargo to run cargo::load_crate in a new thread. This will require some jury rigging, but it'll keep us from having to tweak the parser this close to release.

[catamorphism]

@erickt -- is this bug fixed now that your interner cache fix is merged?

[erickt]

@catamorphism, yep, closing.