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nixpkgs/pkgs/build-support/fetchgit/default.nix
Atemu ee97de3be9 fetchgit: nudge to update the manual when modifying parameters
Many parameters added over the past many years were not documented in the
manual. People likely simple didn't think to do that, so let's nudge them.
2024-11-14 23:50:13 +01:00

104 lines
3.5 KiB
Nix

{lib, stdenvNoCC, git, git-lfs, cacert}: let
urlToName = url: rev: let
inherit (lib) removeSuffix splitString last;
base = last (splitString ":" (baseNameOf (removeSuffix "/" url)));
matched = builtins.match "(.*)\\.git" base;
short = builtins.substring 0 7 rev;
appendShort = lib.optionalString ((builtins.match "[a-f0-9]*" rev) != null) "-${short}";
in "${if matched == null then base else builtins.head matched}${appendShort}";
in
lib.makeOverridable (lib.fetchers.withNormalizedHash { } (
# NOTE Please document parameter additions or changes in
# doc/build-helpers/fetchers.chapter.md
{ url, rev ? "HEAD", leaveDotGit ? deepClone
, outputHash ? lib.fakeHash, outputHashAlgo ? null
, fetchSubmodules ? true, deepClone ? false
, branchName ? null
, sparseCheckout ? []
, nonConeMode ? false
, name ? urlToName url rev
, # Shell code executed after the file has been fetched
# successfully. This can do things like check or transform the file.
postFetch ? ""
, preferLocalBuild ? true
, fetchLFS ? false
, # Shell code to build a netrc file for BASIC auth
netrcPhase ? null
, # Impure env vars (https://nixos.org/nix/manual/#sec-advanced-attributes)
# needed for netrcPhase
netrcImpureEnvVars ? []
, meta ? {}
, allowedRequisites ? null
}:
/* NOTE:
fetchgit has one problem: git fetch only works for refs.
This is because fetching arbitrary (maybe dangling) commits creates garbage collection risks
and checking whether a commit belongs to a ref is expensive. This may
change in the future when some caching is added to git (?)
Usually refs are either tags (refs/tags/*) or branches (refs/heads/*)
Cloning branches will make the hash check fail when there is an update.
But not all patches we want can be accessed by tags.
The workaround is getting the last n commits so that it's likely that they
still contain the hash we want.
for now : increase depth iteratively (TODO)
real fix: ask git folks to add a
git fetch $HASH contained in $BRANCH
facility because checking that $HASH is contained in $BRANCH is less
expensive than fetching --depth $N.
Even if git folks implemented this feature soon it may take years until
server admins start using the new version?
*/
assert deepClone -> leaveDotGit;
assert nonConeMode -> (sparseCheckout != []);
if builtins.isString sparseCheckout then
# Changed to throw on 2023-06-04
throw "Please provide directories/patterns for sparse checkout as a list of strings. Passing a (multi-line) string is not supported any more."
else
stdenvNoCC.mkDerivation {
inherit name;
builder = ./builder.sh;
fetcher = ./nix-prefetch-git;
nativeBuildInputs = [ git cacert ]
++ lib.optionals fetchLFS [ git-lfs ];
inherit outputHash outputHashAlgo;
outputHashMode = "recursive";
# git-sparse-checkout(1) says:
# > When the --stdin option is provided, the directories or patterns are read
# > from standard in as a newline-delimited list instead of from the arguments.
sparseCheckout = builtins.concatStringsSep "\n" sparseCheckout;
inherit url rev leaveDotGit fetchLFS fetchSubmodules deepClone branchName nonConeMode postFetch;
postHook = if netrcPhase == null then null else ''
${netrcPhase}
# required that git uses the netrc file
mv {,.}netrc
export NETRC=$PWD/.netrc
export HOME=$PWD
'';
impureEnvVars = lib.fetchers.proxyImpureEnvVars ++ netrcImpureEnvVars ++ [
"GIT_PROXY_COMMAND" "NIX_GIT_SSL_CAINFO" "SOCKS_SERVER"
];
inherit preferLocalBuild meta allowedRequisites;
passthru = {
gitRepoUrl = url;
};
}
))