Esy Install

But in ocaml this time. With a real solver, so we get good dependencies.

Status: self-hosting! Also can install reason-wall-demo

Completed

• parsing opam files & mostly converting the dependencies (I bail on the more complex boolean operations, pretending they are "any")
• parsing package.json files
• talking to the npm registry
• looking in a local copy of the opam registry
• using MCCS (a SAT solver) to find a valid assignment of dependencies!
• tracking buildDependencies separately
• sharing resolved buildDependencies when possible
• generating a lockfile! (it's yojson at the moment, so don't expect anything fancy)
• fetching all the things, with some opam -> package.json conversion
• write out override files
• get the files from opam too tho
• handle override patches too
• add a _resolved field
• opam conversion
  • incorporate esy-opam-overrides
• get jbuilder building
• get [the test repository] building!
• handle opam versions correctly (>= 1.2.0 & < 1.3.0)
• respect the "available" flag in opam
• get tsdl building ok
• get reason-wall-demo building!
• be able to install its own deps!
• ~ should resolve before the empty string in opam land
• make the "fetch" step not depend on having opam-repository around
• grab & update esy-opam-overrides and opam-repository automatically

After that

• be able to process normal npm dependencies -- first by trying to do it without conflicts, and then relaxing the requirement and doing an after-pass to remove unneeded duplicates.
• output a nice "esy.resolved" file that esy b can then read to know where dependencies live.

Needed less urgently

• use Lwt! So we can parallelize a ton of things
• actually validate checksums
• deciding what we want to do with devDependencies (currently they're dumped into build dependences)
• make the generated lockfile a nicer format (maybe yaml/toml?)
• parallelize some things, but make sure not to compromise reproducability
• handle the not-fresh case
  • inflate from lockfile
  • check staleness
  • add/remove/upgrade deps

Needed for cross-platform

• use Cohttp instead of shelling out to curl
• maybe use an ocaml git client? instead of shelling out to git
• use an ocaml decompression library instead of shelling out to tar
• audit for "/" vs Filename.concat

Later on

• maybe fetch tarballs from the opam mirror directly
• maybe use a global cache for fetched things? currently using a project-local cache
• support multiple architecture targets!