Backport libfetchers from the flakes branch #3459
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andir
reviewed
Mar 30, 2020
andir
reviewed
Mar 30, 2020
|
I like the idea of a |
|
Yes, |
|
Thanks for confirming! |
|
@andir There were a couple of methods that are only used in the flakes branch. I've removed them. |
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 (c169ea5).
This fetchers copies a plain directory (i.e. not a Git/Mercurial
repository) to the store (or does nothing if the path is already a
store path).
One use case is to pin the 'nixpkgs' flake used to build the current
NixOS system, and prevent it from being garbage-collected, via a
system registry entry like this:
{
"from": {
"id": "nixpkgs",
"type": "indirect"
},
"to": {
"type": "path",
"path": "/nix/store/rralhl3wj4rdwzjn16g7d93mibvlr521-source",
"lastModified": 1585388205,
"rev": "b0c285807d6a9f1b7562ec417c24fa1a30ecc31a"
},
"exact": true
}
Note the fake "lastModified" and "rev" attributes that ensure that the
flake gives the same evaluation results as the corresponding
Git/GitHub inputs.
(cherry picked from commit 12f9379)
(cherry picked from commit a6ff66b)
(cherry picked from commit 78ad5b3)
Ma27
added a commit
to Ma27/nix
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May 8, 2020
The original idea was to implement a git-fetcher in Nix's core that supports content hashes[1]. In NixOS#3549[2] it has been suggested to actually use `fetchTree` for this since it's a fairly generic wrapper over the new fetcher-API[3] and already supports content-hashes. This patch implements a new git-fetcher based on `fetchTree` by incorporating the following changes: * Removed the original `fetchGit`-implementation and replaced it with an alias on the `fetchTree` implementation. * Ensured that the `git`-fetcher from `libfetchers` always computes a content-hash and returns an "empty" revision on dirty trees (the latter one is needed to retain backwards-compatibility). * The hash-mismatch error in the fetcher-API exits with code 102 as it usually happens whenever a hash-mismatch is detected by Nix. * Removed the `flakes`-feature-flag: I didn't see a reason why this API is so tightly coupled to the flakes-API and at least `fetchGit` should remain usable without any feature-flags. * It's only possible to specify a `narHash` for a `git`-tree if either a `ref` or a `rev` is given[4]. * It's now possible to specify an URL without a protocol. If it's missing, `file://` is automatically added as it was the case in the original `fetchGit`-implementation. [1] NixOS#3216 [2] NixOS#3549 (comment) [3] NixOS#3459 [4] NixOS#3216 (comment)
Ma27
added a commit
to Ma27/nix
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Jun 4, 2020
The original idea was to implement a git-fetcher in Nix's core that supports content hashes[1]. In NixOS#3549[2] it has been suggested to actually use `fetchTree` for this since it's a fairly generic wrapper over the new fetcher-API[3] and already supports content-hashes. This patch implements a new git-fetcher based on `fetchTree` by incorporating the following changes: * Removed the original `fetchGit`-implementation and replaced it with an alias on the `fetchTree` implementation. * Ensured that the `git`-fetcher from `libfetchers` always computes a content-hash and returns an "empty" revision on dirty trees (the latter one is needed to retain backwards-compatibility). * The hash-mismatch error in the fetcher-API exits with code 102 as it usually happens whenever a hash-mismatch is detected by Nix. * Removed the `flakes`-feature-flag: I didn't see a reason why this API is so tightly coupled to the flakes-API and at least `fetchGit` should remain usable without any feature-flags. * It's only possible to specify a `narHash` for a `git`-tree if either a `ref` or a `rev` is given[4]. * It's now possible to specify an URL without a protocol. If it's missing, `file://` is automatically added as it was the case in the original `fetchGit`-implementation. [1] NixOS#3216 [2] NixOS#3549 (comment) [3] NixOS#3459 [4] NixOS#3216 (comment)
Ma27
added a commit
to Ma27/nix
that referenced
this pull request
Jun 19, 2020
The original idea was to implement a git-fetcher in Nix's core that supports content hashes[1]. In NixOS#3549[2] it has been suggested to actually use `fetchTree` for this since it's a fairly generic wrapper over the new fetcher-API[3] and already supports content-hashes. This patch implements a new git-fetcher based on `fetchTree` by incorporating the following changes: * Removed the original `fetchGit`-implementation and replaced it with an alias on the `fetchTree` implementation. * Ensured that the `git`-fetcher from `libfetchers` always computes a content-hash and returns an "empty" revision on dirty trees (the latter one is needed to retain backwards-compatibility). * The hash-mismatch error in the fetcher-API exits with code 102 as it usually happens whenever a hash-mismatch is detected by Nix. * Removed the `flakes`-feature-flag: I didn't see a reason why this API is so tightly coupled to the flakes-API and at least `fetchGit` should remain usable without any feature-flags. * It's only possible to specify a `narHash` for a `git`-tree if either a `ref` or a `rev` is given[4]. * It's now possible to specify an URL without a protocol. If it's missing, `file://` is automatically added as it was the case in the original `fetchGit`-implementation. [1] NixOS#3216 [2] NixOS#3549 (comment) [3] NixOS#3459 [4] NixOS#3216 (comment)
Ma27
added a commit
to Ma27/nix
that referenced
this pull request
Jul 17, 2020
The original idea was to implement a git-fetcher in Nix's core that supports content hashes[1]. In NixOS#3549[2] it has been suggested to actually use `fetchTree` for this since it's a fairly generic wrapper over the new fetcher-API[3] and already supports content-hashes. This patch implements a new git-fetcher based on `fetchTree` by incorporating the following changes: * Removed the original `fetchGit`-implementation and replaced it with an alias on the `fetchTree` implementation. * Ensured that the `git`-fetcher from `libfetchers` always computes a content-hash and returns an "empty" revision on dirty trees (the latter one is needed to retain backwards-compatibility). * The hash-mismatch error in the fetcher-API exits with code 102 as it usually happens whenever a hash-mismatch is detected by Nix. * Removed the `flakes`-feature-flag: I didn't see a reason why this API is so tightly coupled to the flakes-API and at least `fetchGit` should remain usable without any feature-flags. * It's only possible to specify a `narHash` for a `git`-tree if either a `ref` or a `rev` is given[4]. * It's now possible to specify an URL without a protocol. If it's missing, `file://` is automatically added as it was the case in the original `fetchGit`-implementation. [1] NixOS#3216 [2] NixOS#3549 (comment) [3] NixOS#3459 [4] NixOS#3216 (comment)
Ma27
added a commit
to Ma27/nix
that referenced
this pull request
Jul 27, 2020
The original idea was to implement a git-fetcher in Nix's core that supports content hashes[1]. In NixOS#3549[2] it has been suggested to actually use `fetchTree` for this since it's a fairly generic wrapper over the new fetcher-API[3] and already supports content-hashes. This patch implements a new git-fetcher based on `fetchTree` by incorporating the following changes: * Removed the original `fetchGit`-implementation and replaced it with an alias on the `fetchTree` implementation. * Ensured that the `git`-fetcher from `libfetchers` always computes a content-hash and returns an "empty" revision on dirty trees (the latter one is needed to retain backwards-compatibility). * The hash-mismatch error in the fetcher-API exits with code 102 as it usually happens whenever a hash-mismatch is detected by Nix. * Removed the `flakes`-feature-flag: I didn't see a reason why this API is so tightly coupled to the flakes-API and at least `fetchGit` should remain usable without any feature-flags. * It's only possible to specify a `narHash` for a `git`-tree if either a `ref` or a `rev` is given[4]. * It's now possible to specify an URL without a protocol. If it's missing, `file://` is automatically added as it was the case in the original `fetchGit`-implementation. [1] NixOS#3216 [2] NixOS#3549 (comment) [3] NixOS#3459 [4] NixOS#3216 (comment)
Ma27
added a commit
to Ma27/nix
that referenced
this pull request
Jul 27, 2020
The original idea was to implement a git-fetcher in Nix's core that supports content hashes[1]. In NixOS#3549[2] it has been suggested to actually use `fetchTree` for this since it's a fairly generic wrapper over the new fetcher-API[3] and already supports content-hashes. This patch implements a new git-fetcher based on `fetchTree` by incorporating the following changes: * Removed the original `fetchGit`-implementation and replaced it with an alias on the `fetchTree` implementation. * Ensured that the `git`-fetcher from `libfetchers` always computes a content-hash and returns an "empty" revision on dirty trees (the latter one is needed to retain backwards-compatibility). * The hash-mismatch error in the fetcher-API exits with code 102 as it usually happens whenever a hash-mismatch is detected by Nix. * Removed the `flakes`-feature-flag: I didn't see a reason why this API is so tightly coupled to the flakes-API and at least `fetchGit` should remain usable without any feature-flags. * It's only possible to specify a `narHash` for a `git`-tree if either a `ref` or a `rev` is given[4]. * It's now possible to specify an URL without a protocol. If it's missing, `file://` is automatically added as it was the case in the original `fetchGit`-implementation. [1] NixOS#3216 [2] NixOS#3549 (comment) [3] NixOS#3459 [4] NixOS#3216 (comment)
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This provides a pluggable mechanism for defining new fetchers. It adds a builtin function
fetchTreethat generalizes existing fetchers likefetchGit,fetchMercurialandfetchTarball.fetchTreetakes aset of attributes, e.g.
The existing fetchers are just wrappers around this. Note that the input attributes to
fetchTreeare 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 infetchGitanddownload.cc(e.g.~/.cache/nix/{tarballs,git-revs*}).This also adds support for Git worktrees (c169ea5).