forked from mirrors/nixpkgs
d03a07d5a7
This allow git checkout small parts of a large repo, and avoid fetching unnecessary blobs from server.
95 lines
3.1 KiB
Nix
95 lines
3.1 KiB
Nix
{lib, stdenvNoCC, git, git-lfs, cacert}: let
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urlToName = url: rev: let
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inherit (lib) removeSuffix splitString last;
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base = last (splitString ":" (baseNameOf (removeSuffix "/" url)));
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matched = builtins.match "(.*)\\.git" base;
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short = builtins.substring 0 7 rev;
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appendShort = if (builtins.match "[a-f0-9]*" rev) != null
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then "-${short}"
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else "";
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in "${if matched == null then base else builtins.head matched}${appendShort}";
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in
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{ url, rev ? "HEAD", md5 ? "", sha256 ? "", hash ? "", leaveDotGit ? deepClone
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, fetchSubmodules ? true, deepClone ? false
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, branchName ? null
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, sparseCheckout ? ""
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, name ? urlToName url rev
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, # Shell code executed after the file has been fetched
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# successfully. This can do things like check or transform the file.
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postFetch ? ""
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, preferLocalBuild ? true
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, fetchLFS ? false
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, # Shell code to build a netrc file for BASIC auth
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netrcPhase ? null
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, # Impure env vars (https://nixos.org/nix/manual/#sec-advanced-attributes)
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# needed for netrcPhase
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netrcImpureEnvVars ? []
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}:
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/* NOTE:
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fetchgit has one problem: git fetch only works for refs.
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This is because fetching arbitrary (maybe dangling) commits may be a security risk
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and checking whether a commit belongs to a ref is expensive. This may
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change in the future when some caching is added to git (?)
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Usually refs are either tags (refs/tags/*) or branches (refs/heads/*)
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Cloning branches will make the hash check fail when there is an update.
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But not all patches we want can be accessed by tags.
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The workaround is getting the last n commits so that it's likely that they
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still contain the hash we want.
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for now : increase depth iteratively (TODO)
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real fix: ask git folks to add a
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git fetch $HASH contained in $BRANCH
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facility because checking that $HASH is contained in $BRANCH is less
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expensive than fetching --depth $N.
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Even if git folks implemented this feature soon it may take years until
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server admins start using the new version?
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*/
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assert deepClone -> leaveDotGit;
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if md5 != "" then
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throw "fetchgit does not support md5 anymore, please use sha256"
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else if hash != "" && sha256 != "" then
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throw "Only one of sha256 or hash can be set"
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else
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stdenvNoCC.mkDerivation {
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inherit name;
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builder = ./builder.sh;
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fetcher = ./nix-prefetch-git; # This must be a string to ensure it's called with bash.
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nativeBuildInputs = [ git ]
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++ lib.optionals fetchLFS [ git-lfs ];
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outputHashAlgo = if hash != "" then null else "sha256";
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outputHashMode = "recursive";
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outputHash = if hash != "" then
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hash
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else if sha256 != "" then
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sha256
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else
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lib.fakeSha256;
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inherit url rev leaveDotGit fetchLFS fetchSubmodules deepClone branchName sparseCheckout postFetch;
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postHook = if netrcPhase == null then null else ''
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${netrcPhase}
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# required that git uses the netrc file
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mv {,.}netrc
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export HOME=$PWD
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'';
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GIT_SSL_CAINFO = "${cacert}/etc/ssl/certs/ca-bundle.crt";
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impureEnvVars = lib.fetchers.proxyImpureEnvVars ++ netrcImpureEnvVars ++ [
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"GIT_PROXY_COMMAND" "NIX_GIT_SSL_CAINFO" "SOCKS_SERVER"
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];
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inherit preferLocalBuild;
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}
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