Passing a `gitConfigFile` argument as a string allows setting a custom
git config (as `$GIT_CONFIG_GLOBAL`). The most obvious use is to
override URLs with custom mirrors, but others are possible too.
With this argument fetchgit will make a subdirectory of the Git
repository a root of the resulting store path. This is helpful for
dealing with monorepos where many projects are in separate directories
and don't need a new source hash every time the monorepo is updated.
Commit hash is removed from the name of the derivation to prevent it
from changing the store path when nothing in the subdirectory changes.
Added fetchTags feature to fetchgit, explicit and clear support for
fetching all tags after the source tree fetch completes. Doing this at
build-time in the fetcher is required for packages that invoke commands
like 'git describe' which require tags, and since the nix store is
read-only by design, it is not possible to git fetch --tags at
activation- or run-time. This feature may have been possible by
specifying a postFetch option including calling git fetch --tags,
however doing so obfuscates the solution to this very real problem.
Explicit support for fetching tags should be a first class citizen just
like fetching other refs.
This allows running code to change the environment before the
nix-prefetch-git script is run. In particular, it allows setting things
like NIX_PREFETCH_GIT_CHECKOUT_HOOK, which allows additional code to be
run before deleting the .git directory.
This also means there's potentially value in performing a deep clone
then removing the .git directory, so remove the assertion that prevents
doing so.
This allows tools like `npins` to avoid re-downloading pre-fetched sources at evaluation time,
by setting the same symbolic store path name as `builtins.fetchGit` does,
and would make hacks such as [0] obsolete.
Historical note: `builtins.fetchGit` was introduced in 2016 [1] and
released in 2018 [2]. Before that, there was only the Nixpkgs `fetchgit`,
and the convention for using constant store path names [3] was not established yet [4].
While arguably in retrospect store path names were a mistake, we cannot
undo it here even partially by setting them to a constant, as it would invalidate
countless fixed-output derivations and thus incur an increase in
resource consumption and potentially a large number of build failures.
[0]: f0449d090c
[1]: 38539b943a
[2]: https://github.com/NixOS/nix/releases/tag/2.0
[3]: db00265e81/source/guides/best-practices.md (L263-L264)
[4]: a8603605aa
It's hard to put the sourcing of ./.attrs.sh into all builder
consistently - mistakes will happen. Thus, load structured attrs once in
make-derivation and then source the remaining builder on top.
This should fix quite a few builders with structured attributes in
principle. Most importantly it helps substitute / substituteAll, which
are required for bootstrap on some platforms.
When specifying the `builder` attribute in `stdenv.mkDerivation`, this
will be effectively transformed into
builtins.derivation {
builder = stdenv.shell;
args = [ "-e" builder ];
}
This also means that `default-builder.sh` is never sourced and as a
result it's not guaranteed that `$NIX_ATTRS_SH_FILE` is set to a correct
location[1].
Also, we need to source `.attrs.sh` to source `$stdenv`. So, the
following is done now:
* If `$NIX_ATTRS_SH_FILE` points to a correct location, then use it.
Directly using `.attrs.sh` is problematic for `nix-shell(1)` usage
(see previous commit for more context), so prefer the environment
variable if possible.
* Otherwise, if `.attrs.sh` exists, then use it. See [1] for when this
can happen.
* If neither applies, it can be assumed that `__structuredAttrs` is
turned off and thus nothing needs to be done.
[1] It's possible that it doesn't exist at all - in case of Nix 2.3 or
it can point to a wrong location on older Nix versions with a bug in
`__structuredAttrs`.
This is useful when `leaveDotGit = true` and some other derivation
expects some branch name to exist.
Previously, `nix-prefetch-git` always created a branch with a
hard-coded name (`fetchgit`).
This patch resolves https://github.com/NixOS/nixpkgs/issues/6395. Deep
cloning is useful in combination with 'leaveDotGit' for builds that want
to run "git describe" to obtain a proper version string, etc., like the
'haskellngPackages.cabal2nix' package does.
I think it takes the recent N commits into the repository, which says very little,
even for wanting master/HEAD.
svn path=/nixpkgs/trunk/; revision=18277
