As mentioned in previous commit, Big Sur changes the syntax for the
xpath command slightly.
In the process of testing out replacements for these, I noticed a few
small simplification wins.
- xpath -> xmllint: xpath's cli interface changed in Big Sur
rather than add conditional logic for picking the correct
syntax for xpath, I'm changing to xmllint --xpath, which
appears to be consistent across versions I've tested...
- /plist/dict/key[text()='Writable']/following-sibling::true[1]
doesn't do quite what's expected. It was written to try to
select a <true /> node paired with the Writable key, but it
will also select the *next* <true /> node that appears even
if it was paired with another key.
- I think there's also a logic bug in the conditionals here.
I'm not sure anyone ever actuall saw it, thanks to the xpath
bug, though. With the xpath fix, this conditional passes if /nix
does not exist, / IS writable, and the version is Catalina+.
I think it meant to test for /nix does not exist, / is NOT
writable, and the version is Catalina+. I reworked this lightly
to make it a little clearer at the code level.
This means profiles outside of /nix/var/nix/profiles don't get
garbage-collected. It also means we don't need to scan
/nix/var/nix/profiles for GC roots anymore, except for compatibility
with previously existing generations.
This was broken in 50f13b06fb. Once
again it turns out that putting a bool in a std::variant is a bad
idea, since pointers get silently cast to them...
Otherwise, the steps advertised in this document won't actually work
(e.g. `make install` will fail, trying to access /usr, and
`./inst/bin/nix` won't exist).
The command line options --arg and --argstr that are used by a bunch of
CLI commands to pass arguments to top-level functions in files go
through the same code-path as auto-calling top-level functions with
their default arguments - this, however, was only passing the arguments
that were *explicitly* mentioned in the formals of the function - in the
case of an as-pattern with an ellipsis (eg args @ { ... }) extra passed
arguments would get omitted. This fixes that to instead pass *all*
specified auto args in the case that our function has an ellipsis.
Fixes#598
