diff --git a/src/libfetchers/git-utils.cc b/src/libfetchers/git-utils.cc index a52e2db76..582686412 100644 --- a/src/libfetchers/git-utils.cc +++ b/src/libfetchers/git-utils.cc @@ -205,6 +205,27 @@ static git_packbuilder_progress PACKBUILDER_PROGRESS_CHECK_INTERRUPT = &packBuil } // extern "C" +static void initRepoAtomically(std::filesystem::path &path, bool bare) { + if (pathExists(path.string())) return; + + Path tmpDir = createTempDir(std::filesystem::path(path).parent_path()); + AutoDelete delTmpDir(tmpDir, true); + Repository tmpRepo; + + if (git_repository_init(Setter(tmpRepo), tmpDir.c_str(), bare)) + throw Error("creating Git repository %s: %s", path, git_error_last()->message); + try { + std::filesystem::rename(tmpDir, path); + } catch (std::filesystem::filesystem_error & e) { + if (e.code() == std::errc::file_exists) // Someone might race us to create the repository. + return; + else + throw SysError("moving temporary git repository from %s to %s", tmpDir, path); + } + // we successfully moved the repository, so the temporary directory no longer exists. + delTmpDir.cancel(); +} + struct GitRepoImpl : GitRepo, std::enable_shared_from_this { /** Location of the repository on disk. */ @@ -226,13 +247,9 @@ struct GitRepoImpl : GitRepo, std::enable_shared_from_this { initLibGit2(); - if (pathExists(path.string())) { - if (git_repository_open(Setter(repo), path.string().c_str())) - throw Error("opening Git repository '%s': %s", path, git_error_last()->message); - } else { - if (git_repository_init(Setter(repo), path.string().c_str(), bare)) - throw Error("creating Git repository '%s': %s", path, git_error_last()->message); - } + initRepoAtomically(path, bare); + if (git_repository_open(Setter(repo), path.string().c_str())) + throw Error("opening Git repository %s: %s", path, git_error_last()->message); ObjectDb odb; if (git_repository_odb(Setter(odb), repo.get()))