This is arguably nitpicky, but I think this new formulation is even
clearer. My thinking is that it's easier to comprehend when the
calculated hash value is displayed close to the output path. (I think it
is somewhat similar to eliminating double negatives in logic
statements.)
The formulation is inspired / copied from the OpenEmbedded build tool,
bitbake.
Rather than using $<host-TMPDIR>/nix-build-<drvname>-<number>, the
temporary directory is now always /tmp/nix-build-<drvname>-0. This
improves bitwise-exact reproducibility for builds that store $TMPDIR
in their build output. (Of course, those should still be fixed...)
edolstra:
“…since callers of readDirectory have to handle the possibility of
DT_UNKNOWN anyway, and we don't want to do a stat call for every
directory entry unless it's really needed.”
Some benchmarking suggested this as a good value. Running
$ benchmark -f ... -t 25 -- sh -c 'rm -f /nix/var/nix/binary-cache*; nix-store -r /nix/store/x5z8a2yvz8h6ccmhwrwrp9igg03575jg-nixos-15.09.git.5fd87e1M.drv --dry-run --option binary-caches-parallel-connections <N>'
gave the following mean elapsed times for these values of N:
N=10: 3.3541
N=20: 2.9320
N=25: 2.6690
N=30: 2.9417
N=50: 3.2021
N=100: 3.5718
N=150: 4.2079
Memory usage is also reduced (N=150 used 186 MB, N=25 only 68 MB).
Closes#708.
There is really no conceivable reason why building Nix would need
access to the host's nix.conf. If it does, it's a bug, and we should
fix that instead.
The nixpkgs manual prescribes the use of values from stdenv.lib.licenses
for the meta.license attribute. Those values are attribute sets and
currently skipped when running nix-env with '--xml --meta'. This has the
consequence that also nixpkgs-lint will report missing licenses.
With this commit nix-env with '--xml --meta' will print all attributes
of an attribute set that are of type tString. For example the output for
the package nixpkgs.hello is
<meta name="license" type="strings">
<string type="url" value="http://spdx.org/licenses/GPL-3.0+" />
<string type="shortName" value="gpl3Plus" />
<string type="fullName" value="GNU General Public License v3.0 or later" />
<string type="spdxId" value="GPL-3.0+" />
</meta>
This commit fixes nixpkgs-lint, too.
