Evaluation of attribute sets is strict in the attribute names, which
means immediate evaluation of `with` attribute sets rules out some
potentially interesting use cases (e.g. where the attribute names of one
set depend in some way on another but we want to bring those names into
scope for some values in the second set).
The major example of this is overridable self-referential package sets
(e.g. all-packages.nix). With immediate `with` evaluation, the only
options for such sets are to either make them non-recursive and
explicitly use the name of the overridden set in non-overridden one
every time you want to reference another package, or make the set
recursive and use the `__overrides` hack. As shown in the test case that
comes with this commit, though, delayed `with` evaluation allows a nicer
third alternative.
Signed-off-by: Shea Levy <shea@shealevy.com>
Previously, if the Nix evaluator gets a stack overflow due to a deep
or infinite recursion in the Nix expression, the user gets an
unhelpful message ("Segmentation fault") that doesn't indicate that
the problem is in the user's code rather than Nix itself. Now it
prints:
error: stack overflow (possible infinite recursion)
This only works on x86_64-linux and i686-linux.
Fixes#35.
The kill(2) in Apple's libc follows POSIX semantics, which means that
kill(-1, SIGKILL) will kill the calling process too. Since nix has no
way to distinguish between the process successfully killing everything
and the process being killed by a rogue builder in that case, it can't
safely conclude that killUser was successful.
Luckily, the actual kill syscall takes a parameter that determines
whether POSIX semantics are followed, so we can call that syscall
directly and avoid the issue on Apple.
Signed-off-by: Shea Levy <shea@shealevy.com>
buildPythonPackage does not leave easy_install.pth and site.py
anymore. A python package that leaves these files is broken. An
exception to this is setuptoolsSite which packages setuptools'
site.py. To include it into a buildenv, this patch is even needed, not
just cosmetic.
This reverts commit 69b8f9980f.
The timeout should be enforced remotely. Otherwise, if the garbage
collector is running either locally or remotely, if will block the
build or closure copying for some time. If the garbage collector
takes too long, the build may time out, which is not what we want.
Also, on heavily loaded systems, copying large paths to and from the
remote machine can take a long time, also potentially resulting in a
timeout.
mount(2) with MS_BIND allows mounting a regular file on top of a regular
file, so there's no reason to only bind directories. This allows finer
control over just which files are and aren't included in the chroot
without having to build symlink trees or the like.
Signed-off-by: Shea Levy <shea@shealevy.com>
With C++ std::map, doing a comparison like ‘map["foo"] == ...’ has the
side-effect of adding a mapping from "foo" to the empty string if
"foo" doesn't exist in the map. So we ended up setting some
environment variables by accident.
In particular this means that "trivial" derivations such as writeText
are not substituted, reducing the number of GET requests to the binary
cache by about 200 on a typical NixOS configuration.
This substituter basically cannot work reliably since we switched to
SQLite, since SQLite databases may need write access to open them even
just for reading (and in WAL mode they always do).
For instance, it's pointless to keep copy-from-other-stores running if
there are no other stores, or download-using-manifests if there are no
manifests. This also speeds things up because we don't send queries
to those substituters.
Before calling dumpPath(), we have to make sure the files are owned by
the build user. Otherwise, the build could contain a hard link to
(say) /etc/shadow, which would then be read by the daemon and
rewritten as a world-readable file.
This only affects systems that don't have hard link restrictions
enabled.
The assertion in canonicalisePathMetaData() failed because the
ownership of the path already changed due to the hash rewriting. The
solution is not to check the ownership of rewritten paths.
Issue #122.
Otherwise subsequent invocations of "--repair" will keep rebuilding
the path. This only happens if the path content differs between
builds (e.g. due to timestamps).
Previously, if a binary cache is hanging/unreachable/slow,
download-from-binary-cache.pl would also hang without any indication
to the user. Now, if fetching a URL takes more than 5 seconds, it
will print a message to that effect.
Amazon S3 returns HTTP status code 403 if a file doesn't exist and the
user has no permission to list the contents of the bucket. So treat
it as 404 (meaning it's cached in the NARExistence table).
The "$UID != 0" makes no sense: if the local side has write access to
the Nix store (which is always the case) then it doesn't matter if
we're root - we can import unsigned paths either way.
