mirror of
https://github.com/privatevoid-net/nix-super.git
synced 2024-11-30 01:26:15 +02:00
108 lines
4.4 KiB
XML
108 lines
4.4 KiB
XML
<appendix><title>Bugs / To-Do</title>
|
|
|
|
<itemizedlist>
|
|
|
|
<listitem>
|
|
<para>
|
|
The man-pages generated from the DocBook documentation are ugly.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
Generations properly form a tree. E.g., if after switching to
|
|
generation 39, we perform an installation action, a generation
|
|
43 is created which is a descendant of 39, not 42. So a
|
|
rollback from 43 ought to go back to 39. This is not
|
|
currently implemented; generations form a linear sequence.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
Unify the concepts of successors and substitutes into a
|
|
general notion of <emphasis>equivalent expressions</emphasis>.
|
|
Expressions are equivalent if they have the same target paths
|
|
with the same identifiers. However, even though they are
|
|
functionally equivalent, they may differ stronly with respect
|
|
to their <emphasis>performance characteristics</emphasis>.
|
|
For example, realising a closure expression is more efficient
|
|
that realising the derivation expression from which it was
|
|
produced. On the other hand, distributing sources may be more
|
|
efficient (storage- or bandwidth-wise) than distributing
|
|
binaries. So we need to be able to attach weigths or
|
|
priorities or performance annotations to expressions; Nix can
|
|
then choose the most efficient expression dependent on the
|
|
context.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
<emphasis>Build management.</emphasis> In principle it is already
|
|
possible to do build management using Nix (by writing builders that
|
|
perform appropriate build steps), but the Nix expression language is
|
|
not yet powerful enough to make this pleasant (?). The language should
|
|
be extended with features from the <ulink
|
|
url='http://www.cs.uu.nl/~eelco/maak/'>Maak build manager</ulink>.
|
|
Another interesting idea is to write a <command>make</command>
|
|
implementation that uses Nix as a back-end to support <ulink
|
|
url='http://www.research.att.com/~bs/bs_faq.html#legacy'>legacy</ulink>
|
|
build files.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
There are race conditions between the garbage collector and
|
|
other Nix tools. For instance, when we run
|
|
<command>nix-env</command> to build and install a derivation
|
|
and run the garbage collector at the same time, the garbage
|
|
collector may kick in exactly between the build and
|
|
installation steps, i.e., before the newly built derivation
|
|
has become reachable from a root of the garbage collector.
|
|
</para>
|
|
|
|
<para>
|
|
One solution would be for these programs to properly register
|
|
temporary roots for the collector. Another would be to use
|
|
stop-the-world garbage collection: if any tool is running, the
|
|
garbage collector blocks, and vice versa. These solutions do
|
|
not solve the situation where multiple tools are involved,
|
|
e.g.,
|
|
|
|
<screen>
|
|
$ nix-store -r $(nix-instantiate foo.nix)</screen>
|
|
|
|
since even if <command>nix-instantiate</command> where to
|
|
register a temporary root, it would be released by the time
|
|
<command>nix-store</command> is started. A solution would be
|
|
to write the intermediate value to a file that is used as a
|
|
root to the collector, e.g.,
|
|
|
|
<screen>
|
|
$ nix-instantiate foo.nix > /nix/var/nix/roots/bla
|
|
$ nix-store -r $(cat /nix/var/nix/roots/bla)</screen>
|
|
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem><para>For security, <command>nix-push</command> manifests
|
|
should be digitally signed, and <command>nix-pull</command> should
|
|
verify the signatures. The actual NAR archives in the cache do not
|
|
need to be signed, since the manifest contains cryptographic hashes of
|
|
these files (and <filename>fetchurl.nix</filename> checks
|
|
them).</para></listitem>
|
|
|
|
<listitem><para>We should switch away from MD5, since it has been
|
|
more-or-less cracked. We don't currently depend very much on the
|
|
collision-resistance of MD5, but we will once we start sharing build
|
|
results between users.</para></listitem>
|
|
|
|
<listitem><para>It would be useful to have an option in
|
|
<command>nix-env --delete-generations</command> to remove non-current
|
|
generations older than a certain age.</para></listitem>
|
|
|
|
</itemizedlist>
|
|
|
|
</appendix>
|