Now the derivation outputs are parsed up front, we can avoid a reparse
by doing it. Also, this just feels a bit better as the `output*` env
vars are more of a `libnixexpr` interface than `libnixstore` interface:
ultimately, it's the derivation outputs that decide whether the
derivation is fixed-output.
Yes, hashed mirrors might go away with #3689, but this bit of code would
be moved rather than deleted, so it's worth doing a cleanup anyways I
think.
We have a larger problem that passsing computed strings to the first
variable argument of many exception constructors is unsafe because that
first variable argument is interpreted not as a plain string, but format
string, and if it contains '%' boost::format will abort, since there are
no arguments to the format string.
In this particular instance '%' was used as part of an escape code in a
URL, which, when the download failed, caused Nix to abort displaying the
`FileTransferError`.
Nix installation now requires following redirects using `curl -L`. This
is currently represented on the [Nix download page][] but not in the
manual. This change updates the manual to reflect this.
Using `curl` without the `-L` flag results in an empty body, making
installation a no-op.
[Nix download page]: https://nixos.org/download.html
This is a bit complex because we want to expose extra functionality the
wrapped class has. Perhaps there is some inheritancy trickery to do this
nicer, but I don't know it, and this is the first thing we tried after a
series of attempts that did build.
This design is kind of like that of Rust's Writer, Reader, or Iter
adapters, which impliment more traits based on what the inner type
implements.
This was introduced in fa125b9b28, and
then "reverted" in 1cf4801108, except that
revert left the struct around doing nothing useful.
We're removing it all the way now because we want to make a new
`TeeSink` complementing the already-exiting `TeeSource`, that is
actually a completely different concept as far as the class hierarchy is
concerned.
