Instead of making a complete copy of the repo, fetching the
submodules, and writing the result to the store (which is all
superexpensive), we now fetch the submodules recursively using the Git
fetcher, and return a union accessor that "mounts" the accessors for
the submodules on top of the root accessor.
We now have `schemeName` and `allowedAttrs` functions for this purpose.
We look up the schema with the former; we restrict the set of input
attributes with the latter.
Committing a lock file using markFileChanged() required the input to
be writable by the caller in the local filesystem (using the path
returned by getSourcePath()). putFile() abstracts over this.
Two changes:
* The (probably unintentional) hack to handle paths as tarballs has
been removed. This is almost certainly not what users expect and is
inconsistent with flakeref handling everywhere else.
* The hack to support scp-style Git URLs has been moved to the Git
fetcher, so it's now supported not just by fetchTree but by flake
inputs.
Special-casing the file name is rather ugly, so we shouldn't do
that. So now any {file,http,https} URL is handled by
TarballInputScheme, except for non-flake inputs (i.e. inputs that have
the attribute `flake = false`).
Previously we would completely refetch the submodules from the
network, even though the repo might already have them. Now we copy the
.git/modules directory from the repo as an optimisation. This speeds
up evaluating
builtins.fetchTree { type = "git"; url = "/path/to/blender"; submodules = true; }
(where /path/to/blender already has the needed submodules) from 121s
to 57s.
This is still pretty inefficient and a hack, but a better solution is
best done on the lazy-trees branch.
This change also help in the case where the repo already has the
submodules but the origin is unfetchable for whatever reason
(e.g. there have been cases where Nix in a GitHub action doesn't have
the right authentication set up).
We cannot use 'actualUrl', because for file:// repos that's not the
original URL that the repo was fetched from. This is a problem since
submodules may be relative to the original URL.
Fixes e.g.
nix eval --impure --json --expr 'builtins.fetchTree { type = "git"; url = "/path/to/blender"; submodules = true; }'
where /path/to/blender is a clone of
https://github.com/blender/blender.git (which has several relative
submodules like '../blender-addons.git').
The git fetcher code used to dereference the (potentially empty) `ref`
input attribute. This was magically working, probably because the
compiler somehow outsmarted us, but is now blowing up with newer nixpkgs
versions.
Fix that by not trying to access this field while we don't know for sure
that it has been defined.
Fix#6554
Since a26be9f3b8, the same parser is used
to parse the result of sourcehut’s `HEAD` endpoint (coming from [git
dumb protocol]) and the output of `git ls-remote`. However, they are very
slightly different (the former doesn’t specify the current reference
since it’s implied to be `HEAD`).
Unify both, and make the parser a bit more robust and understandable (by
making it more typed and adding tests for it)
[git dumb protocol]: https://git-scm.com/book/en/v2/Git-Internals-Transfer-Protocols#_the_dumb_protocol
I'm afraid I missed a few problematic `git(1)`-calls while implementing
PR #6440, sorry for that! Upon investigating what went wrong, I realized
that I only tested against the "cached"-case by accident because my
git-checkout with my system's flake was apparently cached during my
debugging.
I managed to trigger the original issue again by running:
$ git commit --allow-empty -m "tmp"
$ sudo nixos-rebuild switch --flake .# -L --builders ''
Since `repoDir` points to the checkout that's potentially owned by
another user, I decided to add `--git-dir` to each call affecting
`repoDir`.
Since the `tmpDir` for the temporary submodule-checkout is created by
Nix itself, it doesn't seem to be an issue.
Sorry for that, it should be fine now.
The previous head caching implementation stored two paths in the local
cache; one for the cached git repo and another textfile containing the
resolved HEAD ref. This commit instead stores the resolved HEAD by
setting the HEAD ref in the local cache appropriately.
The `--git-dir=` must be `.` in some cases (for cached repos that are
"bare" repos in `~/.cache/nix/gitv3`). With this fix we can add
`--git-dir` to each `git`-invokation needed for `nixos-rebuild`.
To demonstrate the problem:
* You need a `git` at 2.33.3 in your $PATH
* An expression like this in a git repository:
``` nix
{
outputs = { self, nixpkgs }: {
packages.foo.x86_64-linux = with nixpkgs.legacyPackages.x86_64-linux;
runCommand "snens" { } ''
echo ${(builtins.fetchGit ./.).lastModifiedDate} > $out
'';
};
}
```
Now, when instantiating the package via `builtins.getFlake`, it fails on
Nix 2.7 like this:
$ nix-instantiate -E '(builtins.getFlake "'"$(pwd)"'").packages.foo.x86_64-linux'
fatal: unsafe repository ('/nix/store/a7j3125km4h8l0p71q6ssfkxamfh5d61-source' is owned by someone else)
To add an exception for this directory, call:
git config --global --add safe.directory /nix/store/a7j3125km4h8l0p71q6ssfkxamfh5d61-source
error: program 'git' failed with exit code 128
(use '--show-trace' to show detailed location information)
This breaks e.g. `nixops`-deployments using flakes with similar
expressions as shown above.
The cause for this is that `git(1)` tries to find the highest
`.git`-directory in the directory tree and if it finds a such a
directory, but with another owning user (root vs. the user who evaluates
the expression), it fails as above. This was changed recently to fix
CVE-2022-24765[1].
By explicitly specifying `--git-dir`, Git assumes to be in the top-level
directory and doesn't attempt to look for a `.git`-directory in the
parent directories and thus the code-path leading to said error is never
reached.
[1] https://lore.kernel.org/git/xmqqv8veb5i6.fsf@gitster.g/
The filter expects all paths to have a prefix of the raw `actualUrl`, but
`Store::addToStore(...)` provides absolute canonicalized paths.
To fix this create an absolute and canonicalized path from the `actualUrl` and
use it instead.
Fixes#6195.
Starting work on #5638
The exact boundary between `FetchSettings` and `EvalSettings` is not
clear to me, but that's fine. First lets clean out `libstore`, and then
worry about what, if anything, should be the separation between those
two.
