From patchwork Mon Jan 11 11:05:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patrick Steinhardt X-Patchwork-Id: 12010237 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B141C433DB for ; Mon, 11 Jan 2021 11:06:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E91822473 for ; Mon, 11 Jan 2021 11:06:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728383AbhAKLGF (ORCPT ); Mon, 11 Jan 2021 06:06:05 -0500 Received: from wout4-smtp.messagingengine.com ([64.147.123.20]:50965 "EHLO wout4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727986AbhAKLGF (ORCPT ); Mon, 11 Jan 2021 06:06:05 -0500 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.west.internal (Postfix) with ESMTP id 04E502934; Mon, 11 Jan 2021 06:05:18 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute1.internal (MEProxy); Mon, 11 Jan 2021 06:05:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pks.im; h=date :from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=fm3; bh=RZec6KzWWuireTLH14zQdN5lvkF jhb7FuWyueGDafM8=; b=KcbSIjgF3jPBEAmHn2/e/uhSx+zkATu/zvE/KPTpWey JRVkQyKqXIHlIJzK35VKF5v+YnsRfLSDjIdJ9O7yr4hoSYnq4+OO1wV/1XWb/wa/ QhpCRATEkFoPa8FznPirdeJR3b1ZqcEZWuNVYIhZnx5dyBXYTA8I+oQQDNKtsw01 Ycih88sMKSGPQYV1wicZzt7uNZ/+SnfgOJ+vadu2mh5cmElhksfwxc/pgbivFf6Z XpDErqdWpCJ122qhWfzHWppv62EbVmfhO6KRZwE6hMOPbMf/dXs0dcdyfxX6b910 dgfl95/xIg+ewwK+jD6A2k0M3GgY//bzte0ICbMO8pQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=RZec6K zWWuireTLH14zQdN5lvkFjhb7FuWyueGDafM8=; b=PH6TtJcKr48Nno4aaJXbg1 205LjObXLTR6nDcdS7nyAJ0J5othW2nt9yZBJERmmrwAHlMr9SnifXrOL22gmpzx ND2LANyZ7slNcgAehXtzyTO/G5umNw+LOwS/pvr8ryFUmse/YKObKstGeZH0L8dv 2R/iLAlg9sPJnkfVSwbF0wvSSUFBb+H5xPwUpA6hH+pv6qXl3Z+f2of7tTuPXKe2 pcxtQwwGEAcAVstGRLZo+VC/qZjeVJzL5RrPo29yJ1vFux6NJju+37mGmHQJXqHt LF7PmRij38p+SCKmzQ5yQGMmaYa/JZZppX7kk+5YPZrwnd+/QOTrpAPwsYO/sgag == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedujedrvdehuddgvdehucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvffukfhfgggtuggjsehgtderredttddvnecuhfhrohhmpefrrghtrhhi tghkucfuthgvihhnhhgrrhguthcuoehpshesphhkshdrihhmqeenucggtffrrghtthgvrh hnpeehgefhtdefueffheekgfffudelffejtdfhvdejkedthfehvdelgfetgfdvtedthfen ucfkphepkeelrddugedrgeehrddujedtnecuvehluhhsthgvrhfuihiivgeptdenucfrrg hrrghmpehmrghilhhfrhhomhepphhssehpkhhsrdhimh X-ME-Proxy: Received: from vm-mail.pks.im (dynamic-089-014-045-170.89.14.pool.telefonica.de [89.14.45.170]) by mail.messagingengine.com (Postfix) with ESMTPA id 1701C1080057; Mon, 11 Jan 2021 06:05:17 -0500 (EST) Received: from localhost (ncase [10.192.0.11]) by vm-mail.pks.im (OpenSMTPD) with ESMTPSA id d993f9a7 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Mon, 11 Jan 2021 11:05:17 +0000 (UTC) Date: Mon, 11 Jan 2021 12:05:16 +0100 From: Patrick Steinhardt To: git@vger.kernel.org Cc: Junio C Hamano , Christian Couder Subject: [PATCH v3 1/5] fetch: extract writing to FETCH_HEAD Message-ID: <61dc19a1cab5b03d07c6635496761108d089eb23.1610362744.git.ps@pks.im> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org When performing a fetch with the default `--write-fetch-head` option, we write all updated references to FETCH_HEAD while the updates are performed. Given that updates are not performed atomically, it means that we we write to FETCH_HEAD even if some or all of the reference updates fail. Given that we simply update FETCH_HEAD ad-hoc with each reference, the logic is completely contained in `store_update_refs` and thus quite hard to extend. This can already be seen by the way we skip writing to the FETCH_HEAD: instead of having a conditional which simply skips writing, we instead open "/dev/null" and needlessly write all updates there. We are about to extend git-fetch(1) to accept an `--atomic` flag which will make the fetch an all-or-nothing operation with regards to the reference updates. This will also require us to make the updates to FETCH_HEAD an all-or-nothing operation, but as explained doing so is not easy with the current layout. This commit thus refactors the wa we write to FETCH_HEAD and pulls out the logic to open, append to, commit and close the file. While this may seem rather over-the top at first, pulling out this logic will make it a lot easier to update the code in a subsequent commit. It also allows us to easily skip writing completely in case `--no-write-fetch-head` was passed. Signed-off-by: Patrick Steinhardt --- builtin/fetch.c | 108 +++++++++++++++++++++++++++++++++++------------- remote.h | 2 +- 2 files changed, 80 insertions(+), 30 deletions(-) diff --git a/builtin/fetch.c b/builtin/fetch.c index ecf8537605..50f0306a92 100644 --- a/builtin/fetch.c +++ b/builtin/fetch.c @@ -897,6 +897,73 @@ static int iterate_ref_map(void *cb_data, struct object_id *oid) return 0; } +struct fetch_head { + FILE *fp; +}; + +static int open_fetch_head(struct fetch_head *fetch_head) +{ + const char *filename = git_path_fetch_head(the_repository); + + if (write_fetch_head) { + fetch_head->fp = fopen(filename, "a"); + if (!fetch_head->fp) + return error_errno(_("cannot open %s"), filename); + } else { + fetch_head->fp = NULL; + } + + return 0; +} + +static void append_fetch_head(struct fetch_head *fetch_head, + const struct object_id *old_oid, + enum fetch_head_status fetch_head_status, + const char *note, + const char *url, size_t url_len) +{ + char old_oid_hex[GIT_MAX_HEXSZ + 1]; + const char *merge_status_marker; + size_t i; + + if (!fetch_head->fp) + return; + + switch (fetch_head_status) { + case FETCH_HEAD_NOT_FOR_MERGE: + merge_status_marker = "not-for-merge"; + break; + case FETCH_HEAD_MERGE: + merge_status_marker = ""; + break; + default: + /* do not write anything to FETCH_HEAD */ + return; + } + + fprintf(fetch_head->fp, "%s\t%s\t%s", + oid_to_hex_r(old_oid_hex, old_oid), merge_status_marker, note); + for (i = 0; i < url_len; ++i) + if ('\n' == url[i]) + fputs("\\n", fetch_head->fp); + else + fputc(url[i], fetch_head->fp); + fputc('\n', fetch_head->fp); +} + +static void commit_fetch_head(struct fetch_head *fetch_head) +{ + /* Nothing to commit yet. */ +} + +static void close_fetch_head(struct fetch_head *fetch_head) +{ + if (!fetch_head->fp) + return; + + fclose(fetch_head->fp); +} + static const char warn_show_forced_updates[] = N_("Fetch normally indicates which branches had a forced update,\n" "but that check has been disabled. To re-enable, use '--show-forced-updates'\n" @@ -909,22 +976,19 @@ N_("It took %.2f seconds to check forced updates. You can use\n" static int store_updated_refs(const char *raw_url, const char *remote_name, int connectivity_checked, struct ref *ref_map) { - FILE *fp; + struct fetch_head fetch_head; struct commit *commit; int url_len, i, rc = 0; struct strbuf note = STRBUF_INIT; const char *what, *kind; struct ref *rm; char *url; - const char *filename = (!write_fetch_head - ? "/dev/null" - : git_path_fetch_head(the_repository)); int want_status; int summary_width = transport_summary_width(ref_map); - fp = fopen(filename, "a"); - if (!fp) - return error_errno(_("cannot open %s"), filename); + rc = open_fetch_head(&fetch_head); + if (rc) + return -1; if (raw_url) url = transport_anonymize_url(raw_url); @@ -953,7 +1017,6 @@ static int store_updated_refs(const char *raw_url, const char *remote_name, want_status++) { for (rm = ref_map; rm; rm = rm->next) { struct ref *ref = NULL; - const char *merge_status_marker = ""; if (rm->status == REF_STATUS_REJECT_SHALLOW) { if (want_status == FETCH_HEAD_MERGE) @@ -1011,26 +1074,10 @@ static int store_updated_refs(const char *raw_url, const char *remote_name, strbuf_addf(¬e, "%s ", kind); strbuf_addf(¬e, "'%s' of ", what); } - switch (rm->fetch_head_status) { - case FETCH_HEAD_NOT_FOR_MERGE: - merge_status_marker = "not-for-merge"; - /* fall-through */ - case FETCH_HEAD_MERGE: - fprintf(fp, "%s\t%s\t%s", - oid_to_hex(&rm->old_oid), - merge_status_marker, - note.buf); - for (i = 0; i < url_len; ++i) - if ('\n' == url[i]) - fputs("\\n", fp); - else - fputc(url[i], fp); - fputc('\n', fp); - break; - default: - /* do not write anything to FETCH_HEAD */ - break; - } + + append_fetch_head(&fetch_head, &rm->old_oid, + rm->fetch_head_status, + note.buf, url, url_len); strbuf_reset(¬e); if (ref) { @@ -1060,6 +1107,9 @@ static int store_updated_refs(const char *raw_url, const char *remote_name, } } + if (!rc) + commit_fetch_head(&fetch_head); + if (rc & STORE_REF_ERROR_DF_CONFLICT) error(_("some local refs could not be updated; try running\n" " 'git remote prune %s' to remove any old, conflicting " @@ -1077,7 +1127,7 @@ static int store_updated_refs(const char *raw_url, const char *remote_name, abort: strbuf_release(¬e); free(url); - fclose(fp); + close_fetch_head(&fetch_head); return rc; } diff --git a/remote.h b/remote.h index 3211abdf05..aad1a0f080 100644 --- a/remote.h +++ b/remote.h @@ -134,7 +134,7 @@ struct ref { * should be 0, so that xcalloc'd structures get it * by default. */ - enum { + enum fetch_head_status { FETCH_HEAD_MERGE = -1, FETCH_HEAD_NOT_FOR_MERGE = 0, FETCH_HEAD_IGNORE = 1