We're getting more reports in https://github.com/NixOS/nix/issues/10985
It appears that something hasn't gone right process-wise.
I find this mistake not to be worth investigating, but rather something
to pay attention to going forward.
Let's nip this in the bud.
Closes https://github.com/NixOS/nix/issues/10985
(cherry picked from commit e948c8e033)
Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
This also reworks the Mercurial fetcher (which was still using the
old cache interface) to have two distinct cache mappings:
* A ref-to-rev mapping, which is store-independent.
* A rev-to-store-path mapping.
All OS and IO operations should be moved out, leaving only some misc
portable pure functions.
This is useful to avoid copious CPP when doing things like Windows and
Emscripten ports.
Newly exposed functions to break cycles:
- `restoreSignals`
- `updateWindowSize`
This provides a pluggable mechanism for defining new fetchers. It adds
a builtin function 'fetchTree' that generalizes existing fetchers like
'fetchGit', 'fetchMercurial' and 'fetchTarball'. 'fetchTree' takes a
set of attributes, e.g.
fetchTree {
type = "git";
url = "https://example.org/repo.git";
ref = "some-branch";
rev = "abcdef...";
}
The existing fetchers are just wrappers around this. Note that the
input attributes to fetchTree are the same as flake input
specifications and flake lock file entries.
All fetchers share a common cache stored in
~/.cache/nix/fetcher-cache-v1.sqlite. This replaces the ad hoc caching
mechanisms in fetchGit and download.cc (e.g. ~/.cache/nix/{tarballs,git-revs*}).
This also adds support for Git worktrees (c169ea5904).
