Tim's journal

Today I was able to finish the first three items on the "Build all of Servo" milestone on the schedule:

• Sub-package-IDs allow you to name a subdirectory of a package directory by its own package ID. For example, if your package foo has an extras directory with several subdirectories, and foo/extras/baz has a crate file in it, you can rustpkg build foo/extras/baz without building the other crates in the foo package. This pull request landed already.
  
• Recursive dependencies: actually, this almost worked before, and it was a matter of fixing a bug that assumed that all of the dependencies for a package (except for system libraries) were in the same workspace. This is building on the bots and should land in another ten minutes or so.
  
• Installing to RUST_PATH: previously, rustpkg would install a package to the same workspace its sources were in. Now, it installs the package to the first workspace in RUST_PATH, if you've set a RUST_PATH in the environment; if you didn't, it defaults to the old behavior. This is in the queue to build.
  

I'm working on putting build output in a target-specific subdirectory now, which is easy except for cleaning up all of my crufty test code that made assumptions in lots of different places about the directory structure. Along those lines, I'm also cleaning up some of the test code to make it less crufty.

I looked at #7879 (infinite loop compiling dependencies) too, and it's harder than I thought; right now, rustpkg assumes it's okay to build the crates in a multi-crate package in any order. That's not necessarily true (as the examples given in the original bug and in my comment show) and so rustpkg can end up telling workcache that there's a circular dependency between two files (when there's not). I think fixing this will require topologically sorting the crates in a package in dependency order, which in turn will actually require... writing a graph library in Rust, since there isn't one. So that will be fun, but I don't have time today.