From patchwork Thu Apr 7 21:53:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "brian m. carlson" X-Patchwork-Id: 12805829 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEFCBC433F5 for ; Thu, 7 Apr 2022 22:08:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231883AbiDGWKZ (ORCPT ); Thu, 7 Apr 2022 18:10:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230128AbiDGWKY (ORCPT ); Thu, 7 Apr 2022 18:10:24 -0400 Received: from ring.crustytoothpaste.net (ring.crustytoothpaste.net [IPv6:2600:3c04::f03c:92ff:fe9e:c6d8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E047FE0BC for ; Thu, 7 Apr 2022 14:54:00 -0700 (PDT) Received: from camp.crustytoothpaste.net (unknown [IPv6:2001:470:b056:101:a6ae:7d13:8741:9028]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by ring.crustytoothpaste.net (Postfix) with ESMTPSA id 0AF815A3F1; Thu, 7 Apr 2022 21:54:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=crustytoothpaste.net; s=default; t=1649368440; bh=mDGuLV8bLSKzdfGvYq1Uk8ncGktMtJirKeEWCm2o+Aw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:Content-Type:From: Reply-To:Subject:Date:To:CC:Resent-Date:Resent-From:Resent-To: Resent-Cc:In-Reply-To:References:Content-Type:Content-Disposition; b=Xk+tQDLdJKsDcH2t2qJhfMnkzlOkSpi2s9BK/r53r8m4TxkCCps+YukgD1WN9UCvV InW+f+2QoaiYmfGuxeKZrZPWOBjm9oQeaKnlqb/iLh6v4aqA1IX7xBnxFTZ1z7DkQ6 JlyJbA3+aRh9pku+TJjBQ359sorndliANUKKBpH49u49ztz2OtatWdXHw8pVXVGDlN r7yCpH7VuNge3MsKG/Lc6d00uKLGo18Wexvf3cX2PqYN0dXxbD0FpF3BOLK8RrDj4Z A7IysOomqoX2SAvFro1kkhAAf6oNYARwAbLAlHEvi7fgCptZlLj0hP5PF8WtUMGIqf jo7ZdnqBs4dWhh7d/CjBAR0oNEU285VMbhwIenZlNCVMjIcYDafdCEkROAkeni0KIK IH+2JIK3GQ+DAdePqIBU9zCynHMOy2OeEWr43E2YHbLmP22nWIBWrC7Iof2TebyBp4 /8ZZpVm3nszHj51ON+Lz+rTCQh2zpbO4WRnG1HBcyzsCt92Jpcm From: "brian m. carlson" To: Cc: Junio C Hamano , Phillip Wood , =?utf-8?b?w4Z2YXIgQXJuZmrDtnI=?= =?utf-8?b?w7AgQmphcm1hc29u?= Subject: [PATCH v4 3/4] builtin/stash: provide a way to export stashes to a ref Date: Thu, 7 Apr 2022 21:53:51 +0000 Message-Id: <20220407215352.3491567-4-sandals@crustytoothpaste.net> X-Mailer: git-send-email 2.35.1.473.g83b2b277ed In-Reply-To: <20220407215352.3491567-1-sandals@crustytoothpaste.net> References: <20220310173236.4165310-1-sandals@crustytoothpaste.net> <20220407215352.3491567-1-sandals@crustytoothpaste.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org A common user problem is how to sync in-progress work to another machine. Users currently must use some sort of transfer of the working tree, which poses security risks and also necessarily causes the index to become dirty. The experience is suboptimal and frustrating for users. A reasonable idea is to use the stash for this purpose, but the stash is stored in the reflog, not in a ref, and as such it cannot be pushed or pulled. This also means that it cannot be saved into a bundle or preserved elsewhere, which is a problem when using throwaway development environments. Let's solve this problem by allowing the user to export the stash to a ref (or, to just write it into the repository and print the hash, à la git commit-tree). Introduce git stash export, which writes a chain of commits where the first parent is always a chain to the previous stash, or to a single, empty commit (for the final item) and the second is the stash commit normally written to the reflog. Iterate over each stash from topmost to bottomost, looking up the data for each one, and then create the chain from the single empty commit back up in reverse order. Generate a predictable empty commit so our behavior is reproducible. Create a useful commit message, preserving the author and committer information, to help users identify stash commits when viewing them as normal commits. If the user has specified specific stashes they'd like to export instead, use those instead of iterating over all of the stashes. As part of this, specifically request quiet behavior when looking up the OID for a revision because we will eventually hit a revision that doesn't exist and we don't want to die when that occurs. Signed-off-by: brian m. carlson --- Documentation/git-stash.txt | 22 ++++- builtin/stash.c | 182 ++++++++++++++++++++++++++++++++++++ 2 files changed, 203 insertions(+), 1 deletion(-) diff --git a/Documentation/git-stash.txt b/Documentation/git-stash.txt index 6e15f47525..162110314e 100644 --- a/Documentation/git-stash.txt +++ b/Documentation/git-stash.txt @@ -20,6 +20,7 @@ SYNOPSIS 'git stash' clear 'git stash' create [] 'git stash' store [-m|--message ] [-q|--quiet] +'git stash' export ( --print | --to-ref ) [...] DESCRIPTION ----------- @@ -151,6 +152,12 @@ store:: reflog. This is intended to be useful for scripts. It is probably not the command you want to use; see "push" above. +export ( --print | --to-ref ) [...]:: + + Export the specified stashes, or all of them if none are specified, to + a chain of commits which can be transferred using the normal fetch and + push mechanisms, then imported using the `import` subcommand. + OPTIONS ------- -a:: @@ -239,6 +246,19 @@ literally (including newlines and quotes). + Quiet, suppress feedback messages. +--print:: + This option is only valid for `export`. ++ +Create the chain of commits representing the exported stashes without +storing it anywhere in the ref namespace and print the object ID to +standard output. This is designed for scripts. + +--to-ref:: + This option is only valid for `export`. ++ +Create the chain of commits representing the exported stashes and store +it to the specified ref. + \--:: This option is only valid for `push` command. + @@ -256,7 +276,7 @@ For more details, see the 'pathspec' entry in linkgit:gitglossary[7]. :: This option is only valid for `apply`, `branch`, `drop`, `pop`, - `show` commands. + `show`, and `export` commands. + A reference of the form `stash@{}`. When no `` is given, the latest stash is assumed (that is, `stash@{0}`). diff --git a/builtin/stash.c b/builtin/stash.c index b677739bcd..07b0897eda 100644 --- a/builtin/stash.c +++ b/builtin/stash.c @@ -33,6 +33,7 @@ static const char * const git_stash_usage[] = { " [--] [...]]"), N_("git stash save [-p|--patch] [-S|--staged] [-k|--[no-]keep-index] [-q|--quiet]\n" " [-u|--include-untracked] [-a|--all] []"), + N_("git stash export (--print | --to-ref ) [...]"), NULL }; @@ -89,6 +90,12 @@ static const char * const git_stash_save_usage[] = { NULL }; +static const char * const git_stash_export_usage[] = { + N_("git stash export (--print | --to-ref ) [...]"), + NULL +}; + + static const char ref_stash[] = "refs/stash"; static struct strbuf stash_index_path = STRBUF_INIT; @@ -1775,6 +1782,179 @@ static int save_stash(int argc, const char **argv, const char *prefix) return ret; } +static int write_commit_with_parents(struct object_id *out, const struct object_id *oid, struct commit_list *parents) +{ + size_t author_len, committer_len; + struct commit *this; + const char *orig_author, *orig_committer; + char *author = NULL, *committer = NULL; + const char *buffer; + unsigned long bufsize; + const char *p; + struct strbuf msg = STRBUF_INIT; + int ret = 0; + + this = lookup_commit_reference(the_repository, oid); + buffer = get_commit_buffer(this, &bufsize); + orig_author = find_commit_header(buffer, "author", &author_len); + orig_committer = find_commit_header(buffer, "committer", &committer_len); + p = memmem(buffer, bufsize, "\n\n", 2); + + if (!orig_author || !orig_committer || !p) { + ret = error(_("cannot parse commit %s"), oid_to_hex(oid)); + goto out; + } + /* Jump to message. */ + p += 2; + strbuf_addstr(&msg, "git stash: "); + strbuf_add(&msg, p, bufsize - (p - buffer)); + + author = xmemdupz(orig_author, author_len); + committer = xmemdupz(orig_committer, committer_len); + + if (commit_tree_extended(msg.buf, msg.len, + the_hash_algo->empty_tree, parents, + out, author, committer, + NULL, NULL)) { + ret = error(_("could not write commit")); + goto out; + } +out: + strbuf_release(&msg); + unuse_commit_buffer(this, buffer); + free(author); + free(committer); + return ret; +} + +static int do_export_stash(const char *ref, int argc, const char **argv) +{ + struct object_id base; + struct object_context unused; + struct commit *prev; + struct object_id *items = NULL; + int nitems = 0, nalloc = 0; + int res = 0; + int i; + struct strbuf revision = STRBUF_INIT; + const char *author, *committer; + + /* + * This is an arbitrary, fixed date, specifically the one used by git + * format-patch. The goal is merely to produce reproducible output. + */ + prepare_fallback_ident("git stash", "git@stash"); + author = fmt_ident("git stash", "git@stash", WANT_BLANK_IDENT, + "2001-09-17T00:00:00Z", 0); + committer = fmt_ident("git stash", "git@stash", WANT_BLANK_IDENT, + "2001-09-17T00:00:00Z", 0); + + /* First, we create a single empty commit. */ + if (commit_tree_extended(NULL, 0, the_hash_algo->empty_tree, NULL, + &base, author, committer, NULL, NULL)) + return error(_("unable to write base commit")); + + prev = lookup_commit_reference(the_repository, &base); + + if (argc) { + /* + * Find each specified stash, and load data into the array. + */ + for (i = 0; i < argc; i++) { + ALLOC_GROW_BY(items, nitems, 1, nalloc); + if (parse_revision(&revision, argv[i], 1) || + get_oid_with_context(the_repository, revision.buf, + GET_OID_QUIETLY | GET_OID_GENTLY, + &items[i], &unused)) { + res = error(_("unable to find stash entry %s"), argv[i]); + goto out; + } + } + } else { + /* + * Walk the reflog, finding each stash entry, and load data into the + * array. + */ + for (i = 0;; i++) { + char buf[32]; + struct object_id oid; + + snprintf(buf, sizeof(buf), "%d", i); + if (parse_revision(&revision, buf, 1) || + get_oid_with_context(the_repository, revision.buf, + GET_OID_QUIETLY | GET_OID_GENTLY, + &oid, &unused)) + break; + ALLOC_GROW_BY(items, nitems, 1, nalloc); + oidcpy(&items[i], &oid); + } + } + + /* + * Now, create a set of commits identical to the regular stash commits, + * but where their first parents form a chain to our original empty + * base commit. + */ + for (i = nitems - 1; i >= 0; i--) { + struct commit_list *parents = NULL; + struct commit_list **next = &parents; + struct object_id out; + + next = commit_list_append(prev, next); + next = commit_list_append(lookup_commit_reference(the_repository, &items[i]), next); + res = write_commit_with_parents(&out, &items[i], parents); + if (res) + goto out; + prev = lookup_commit_reference(the_repository, &out); + } + if (ref) + update_ref(NULL, ref, &prev->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR); + else + puts(oid_to_hex(&prev->object.oid)); +out: + strbuf_release(&revision); + free(items); + + return res; +} + +enum export_action { + ACTION_NONE, + ACTION_PRINT, + ACTION_TO_REF, +}; + +static int export_stash(int argc, const char **argv, const char *prefix) +{ + const char *ref = NULL; + enum export_action action = ACTION_NONE; + struct option options[] = { + OPT_CMDMODE(0, "print", &action, + N_("print the object ID instead of writing it to a ref"), + ACTION_PRINT), + OPT_CMDMODE(0, "to-ref", &action, + N_("save the data to the given ref"), + ACTION_TO_REF), + OPT_END() + }; + + argc = parse_options(argc, argv, prefix, options, + git_stash_export_usage, + PARSE_OPT_KEEP_DASHDASH); + + if (action == ACTION_NONE) { + return error(_("exactly one of --print and --to-ref is required")); + } else if (action == ACTION_TO_REF) { + if (!argc) + return error(_("--to-ref requires an argument")); + ref = argv[0]; + argc--; + argv++; + } + + return do_export_stash(ref, argc, argv); +} + int cmd_stash(int argc, const char **argv, const char *prefix) { pid_t pid = getpid(); @@ -1818,6 +1998,8 @@ int cmd_stash(int argc, const char **argv, const char *prefix) return !!push_stash(argc, argv, prefix, 0); else if (!strcmp(argv[0], "save")) return !!save_stash(argc, argv, prefix); + else if (!strcmp(argv[0], "export")) + return !!export_stash(argc, argv, prefix); else if (*argv[0] != '-') usage_msg_optf(_("unknown subcommand: %s"), git_stash_usage, options, argv[0]);