This is used by some build tools to provide reproducible builds. See
https://reproducible-builds.org/specs/source-date-epoch/
for more info.
Later, we'll want to set this to a more intelligent value (such as the
most recent mtime of any source file).
So far if no configure script is found or no makefile,
the rest of the phase is skipped, *including* post-hooks.
I find that behavior unexpected/unintuitive.
Earlier version of this patch had problems due to me assuming
that $configureScript is always a simple path, but that turned out
to be false in many cases, e.g. perl.
- IMO using a temporary is not needed here (anymore),
- temporary at that location can cause a problem (in a specific case):
for example, when using the substituteAll function from nixpkgs
on a single file directly under /nix/store/ (or ./foo-file),
the stdenv's substitute tries to create a temporary directly under
/nix/store, which causes problems on chrooted darwin
(according to @copumpkin earlier today on IRC)
Getting the names of all environment variables is tricky. The previous
implementation easily got confused by multi-line variables. The new
one is more reliable but not still not perfect.
This works around a segfault in Bash 4.3, where the expression
"${!var}" (where var="-9") crashes under certain conditions.
http://hydra.nixos.org/build/16693445
Otherwise, stdenv won't have a reference to e.g. patchelf on Linux
(because it was passed in by mkDerivation). This causes the installer
tests to fail, because having "stdenv" in the installation CD closure
is not enough to pull in all stdenv packages.
http://hydra.nixos.org/build/16546643
Now gcc is just another build input, making it possible in the future
to have a stdenv that doesn't depend on a C compiler. This is very
useful on NixOS, since it would allow trivial builders like
writeTextFile to work without pulling in the C compiler.
If $src refers to a directory, then always copy it. Previously, we
checked the extension first, so if the directory had an extension like
.tar, unpackPhase would fail.
If a build input is a regular file, use it as a setup hook. This makes
setup hooks more efficient to create: you don't need a derivation that
copies them to $out/nix-support/setup-hook, instead you can use the
file as is.
You can now register multiple values per named hook, e.g.
addHook preConfigure "echo foo"
addHook preConfigure "echo bar"
will cause ‘runHook preConfigure’ to run both ‘echo foo’ and ‘echo
bar’ (in that order). It will also call the shell function
preConfigure() or eval the shell variable $preConfigure, if
defined. Thus, if you don't call addHook, it works like the old hook
mechanism.
Allowing multiple hooks makes stdenv more modular and extensible. For
instance, multiple setup hooks can define a preFixup hook, and all of
these will be executed.
setup.sh uses the anti-pattern `for f in $(find ...); do` in several
places. `find` returns one path per line, but `for` splits its arguments
by words, so paths which contain spaces are incorrectly split! The
correct way is `find ... | while read f; do`