forked from lix-project/lix
02098d2073
The current usage technically works by putting multiple different repos in to the same git directory. However, it is very slow as Git tries very hard to find common commits between the two repositories. If the two repositories are large (like Nixpkgs and another long-running project,) it is maddeningly slow. This change busts the cache for existing deployments, but users will be promptly repaid in per-repository performance.
246 lines
7.6 KiB
C++
246 lines
7.6 KiB
C++
#include "primops.hh"
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#include "eval-inline.hh"
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#include "download.hh"
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#include "store-api.hh"
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#include "pathlocks.hh"
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#include "hash.hh"
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#include <sys/time.h>
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#include <regex>
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#include <nlohmann/json.hpp>
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using namespace std::string_literals;
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namespace nix {
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struct GitInfo
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{
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Path storePath;
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std::string rev;
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std::string shortRev;
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uint64_t revCount = 0;
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};
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std::regex revRegex("^[0-9a-fA-F]{40}$");
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GitInfo exportGit(ref<Store> store, const std::string & uri,
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std::experimental::optional<std::string> ref, std::string rev,
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const std::string & name)
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{
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if (evalSettings.pureEval && rev == "")
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throw Error("in pure evaluation mode, 'fetchGit' requires a Git revision");
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if (!ref && rev == "" && hasPrefix(uri, "/") && pathExists(uri + "/.git")) {
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bool clean = true;
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try {
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runProgram("git", true, { "-C", uri, "diff-index", "--quiet", "HEAD", "--" });
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} catch (ExecError e) {
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if (!WIFEXITED(e.status) || WEXITSTATUS(e.status) != 1) throw;
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clean = false;
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}
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if (!clean) {
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/* This is an unclean working tree. So copy all tracked
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files. */
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GitInfo gitInfo;
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gitInfo.rev = "0000000000000000000000000000000000000000";
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gitInfo.shortRev = std::string(gitInfo.rev, 0, 7);
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auto files = tokenizeString<std::set<std::string>>(
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runProgram("git", true, { "-C", uri, "ls-files", "-z" }), "\0"s);
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PathFilter filter = [&](const Path & p) -> bool {
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assert(hasPrefix(p, uri));
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std::string file(p, uri.size() + 1);
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auto st = lstat(p);
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if (S_ISDIR(st.st_mode)) {
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auto prefix = file + "/";
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auto i = files.lower_bound(prefix);
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return i != files.end() && hasPrefix(*i, prefix);
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}
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return files.count(file);
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};
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gitInfo.storePath = store->addToStore("source", uri, true, htSHA256, filter);
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return gitInfo;
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}
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// clean working tree, but no ref or rev specified. Use 'HEAD'.
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rev = chomp(runProgram("git", true, { "-C", uri, "rev-parse", "HEAD" }));
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ref = "HEAD"s;
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}
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if (!ref) ref = "HEAD"s;
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if (rev != "" && !std::regex_match(rev, revRegex))
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throw Error("invalid Git revision '%s'", rev);
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Path cacheDir = getCacheDir() + "/nix/gitv2/" + hashString(htSHA256, uri).to_string(Base32, false);
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if (!pathExists(cacheDir)) {
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createDirs(dirOf(cacheDir));
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runProgram("git", true, { "init", "--bare", cacheDir });
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}
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std::string localRef = hashString(htSHA256, fmt("%s-%s", uri, *ref)).to_string(Base32, false);
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Path localRefFile = cacheDir + "/refs/heads/" + localRef;
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bool doFetch;
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time_t now = time(0);
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/* If a rev was specified, we need to fetch if it's not in the
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repo. */
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if (rev != "") {
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try {
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runProgram("git", true, { "-C", cacheDir, "cat-file", "-e", rev });
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doFetch = false;
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} catch (ExecError & e) {
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if (WIFEXITED(e.status)) {
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doFetch = true;
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} else {
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throw;
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}
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}
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} else {
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/* If the local ref is older than ‘tarball-ttl’ seconds, do a
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git fetch to update the local ref to the remote ref. */
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struct stat st;
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doFetch = stat(localRefFile.c_str(), &st) != 0 ||
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st.st_mtime + settings.tarballTtl <= now;
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}
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if (doFetch)
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{
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Activity act(*logger, lvlTalkative, actUnknown, fmt("fetching Git repository '%s'", uri));
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// FIXME: git stderr messes up our progress indicator, so
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// we're using --quiet for now. Should process its stderr.
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runProgram("git", true, { "-C", cacheDir, "fetch", "--quiet", "--force", "--", uri, *ref + ":" + localRef });
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struct timeval times[2];
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times[0].tv_sec = now;
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times[0].tv_usec = 0;
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times[1].tv_sec = now;
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times[1].tv_usec = 0;
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utimes(localRefFile.c_str(), times);
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}
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// FIXME: check whether rev is an ancestor of ref.
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GitInfo gitInfo;
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gitInfo.rev = rev != "" ? rev : chomp(readFile(localRefFile));
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gitInfo.shortRev = std::string(gitInfo.rev, 0, 7);
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printTalkative("using revision %s of repo '%s'", gitInfo.rev, uri);
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std::string storeLinkName = hashString(htSHA512, name + std::string("\0"s) + gitInfo.rev).to_string(Base32, false);
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Path storeLink = cacheDir + "/" + storeLinkName + ".link";
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PathLocks storeLinkLock({storeLink}, fmt("waiting for lock on '%1%'...", storeLink)); // FIXME: broken
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try {
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auto json = nlohmann::json::parse(readFile(storeLink));
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assert(json["name"] == name && json["rev"] == gitInfo.rev);
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gitInfo.storePath = json["storePath"];
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if (store->isValidPath(gitInfo.storePath)) {
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gitInfo.revCount = json["revCount"];
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return gitInfo;
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}
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} catch (SysError & e) {
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if (e.errNo != ENOENT) throw;
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}
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// FIXME: should pipe this, or find some better way to extract a
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// revision.
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auto tar = runProgram("git", true, { "-C", cacheDir, "archive", gitInfo.rev });
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Path tmpDir = createTempDir();
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AutoDelete delTmpDir(tmpDir, true);
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runProgram("tar", true, { "x", "-C", tmpDir }, tar);
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gitInfo.storePath = store->addToStore(name, tmpDir);
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gitInfo.revCount = std::stoull(runProgram("git", true, { "-C", cacheDir, "rev-list", "--count", gitInfo.rev }));
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nlohmann::json json;
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json["storePath"] = gitInfo.storePath;
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json["uri"] = uri;
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json["name"] = name;
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json["rev"] = gitInfo.rev;
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json["revCount"] = gitInfo.revCount;
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writeFile(storeLink, json.dump());
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return gitInfo;
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}
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static void prim_fetchGit(EvalState & state, const Pos & pos, Value * * args, Value & v)
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{
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std::string url;
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std::experimental::optional<std::string> ref;
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std::string rev;
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std::string name = "source";
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PathSet context;
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state.forceValue(*args[0]);
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if (args[0]->type == tAttrs) {
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state.forceAttrs(*args[0], pos);
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for (auto & attr : *args[0]->attrs) {
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string n(attr.name);
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if (n == "url")
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url = state.coerceToString(*attr.pos, *attr.value, context, false, false);
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else if (n == "ref")
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ref = state.forceStringNoCtx(*attr.value, *attr.pos);
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else if (n == "rev")
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rev = state.forceStringNoCtx(*attr.value, *attr.pos);
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else if (n == "name")
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name = state.forceStringNoCtx(*attr.value, *attr.pos);
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else
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throw EvalError("unsupported argument '%s' to 'fetchGit', at %s", attr.name, *attr.pos);
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}
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if (url.empty())
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throw EvalError(format("'url' argument required, at %1%") % pos);
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} else
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url = state.coerceToString(pos, *args[0], context, false, false);
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if (!isUri(url)) url = absPath(url);
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// FIXME: git externals probably can be used to bypass the URI
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// whitelist. Ah well.
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state.checkURI(url);
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auto gitInfo = exportGit(state.store, url, ref, rev, name);
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state.mkAttrs(v, 8);
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mkString(*state.allocAttr(v, state.sOutPath), gitInfo.storePath, PathSet({gitInfo.storePath}));
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mkString(*state.allocAttr(v, state.symbols.create("rev")), gitInfo.rev);
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mkString(*state.allocAttr(v, state.symbols.create("shortRev")), gitInfo.shortRev);
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mkInt(*state.allocAttr(v, state.symbols.create("revCount")), gitInfo.revCount);
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v.attrs->sort();
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if (state.allowedPaths)
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state.allowedPaths->insert(gitInfo.storePath);
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}
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static RegisterPrimOp r("fetchGit", 1, prim_fetchGit);
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}
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