From patchwork Tue May 14 01:14:33 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Junio C Hamano X-Patchwork-Id: 13663740 Received: from pb-smtp20.pobox.com (pb-smtp20.pobox.com [173.228.157.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D6EB5EC5 for ; Tue, 14 May 2024 01:14:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=173.228.157.52 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715649293; cv=none; b=FVhSfKOMI/Tt95pItXshLvb9ThP1EZh4Gidsc/FrJU62yoKzoKAYHCISAkprfbt3yK1v1+avArcih4uc6S7yxDz6kfHYc8Q2VWkJRtjZQd+Kw9s7Wko2VKfg66DTzT2wyZzESt1HrV1AE3eCtk0rfhx8STydVtM0VYeBkujaTfM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715649293; c=relaxed/simple; bh=AqaurW/LXawFDSXmXK7KM1kVdAWnDy3VG/UXnz0jUIU=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pHlL2bMgLkYHamH9tDQwfEunu/QRRjWqvM69/f9YS4Qi3qDSEcJXu7d85de4x5Vaqx1FrzNkEcFfgiUFhKz6BjmTV3a8+6aHdMoCHfHPupk4I7PRWg0shuZYJ+1KFe33HbWCriLZ2YS2SP3obmIPGcVvp8vZBP2K8kYwGmGE66w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=pobox.com; spf=pass smtp.mailfrom=pobox.com; dkim=pass (1024-bit key) header.d=pobox.com header.i=@pobox.com header.b=U9lnmDJs; arc=none smtp.client-ip=173.228.157.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=pobox.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pobox.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=pobox.com header.i=@pobox.com header.b="U9lnmDJs" Received: from pb-smtp20.pobox.com (unknown [127.0.0.1]) by pb-smtp20.pobox.com (Postfix) with ESMTP id 7ED7A389E1; Mon, 13 May 2024 21:14:51 -0400 (EDT) (envelope-from gitster@pobox.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=pobox.com; h=from:to :subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; s=sasl; bh=AqaurW/LXawFDSXmXK7KM1kVd AWnDy3VG/UXnz0jUIU=; b=U9lnmDJsCfJ+AafZMxZzO4UPaKCdqrAdAZdU9bOfY J1Oa8KeTn/e361jBrWZBRTt/R37R+lbBRX4UFdO7J9IImYxFODNhN/6dZQtioN5y Hqoqfm9XCxaPjenCUhrRZfrbht9YZwJN7Pom1qPIdsHMhMMxzM88Il8+SzMs3+Hm uc= Received: from pb-smtp20.sea.icgroup.com (unknown [127.0.0.1]) by pb-smtp20.pobox.com (Postfix) with ESMTP id 3D584389E0; Mon, 13 May 2024 21:14:51 -0400 (EDT) (envelope-from gitster@pobox.com) Received: from pobox.com (unknown [34.125.153.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pb-smtp20.pobox.com (Postfix) with ESMTPSA id 44B5E389D9; Mon, 13 May 2024 21:14:45 -0400 (EDT) (envelope-from gitster@pobox.com) From: Junio C Hamano To: git@vger.kernel.org Subject: [PATCH v4 1/5] setup: add an escape hatch for "no more default hash algorithm" change Date: Mon, 13 May 2024 18:14:33 -0700 Message-ID: <20240514011437.3779151-2-gitster@pobox.com> X-Mailer: git-send-email 2.45.0-145-g3e4a232f6e In-Reply-To: <20240514011437.3779151-1-gitster@pobox.com> References: <20240514011437.3779151-1-gitster@pobox.com> Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Pobox-Relay-ID: 5998C7DC-118F-11EF-A18F-F515D2CDFF5E-77302942!pb-smtp20.pobox.com Partially revert c8aed5e8 (repository: stop setting SHA1 as the default object hash, 2024-05-07), to keep end-user systems still broken when we have gap in our test coverage but yet give them an escape hatch to set the GIT_DEFAULT_HASH environment variable to "sha1" in order to revert to the previous behaviour. This variable has been in use for using SHA-256 hash by default, and it should be a better fit than inventing a new and test-only knob. Signed-off-by: Junio C Hamano --- environment.h | 1 + repository.c | 40 ++++++++++++++++++++++++++++++++++++++++ setup.c | 2 -- 3 files changed, 41 insertions(+), 2 deletions(-) diff --git a/environment.h b/environment.h index 05fd94d7be..deaa29408f 100644 --- a/environment.h +++ b/environment.h @@ -56,6 +56,7 @@ const char *getenv_safe(struct strvec *argv, const char *name); #define GIT_OPTIONAL_LOCKS_ENVIRONMENT "GIT_OPTIONAL_LOCKS" #define GIT_TEXT_DOMAIN_DIR_ENVIRONMENT "GIT_TEXTDOMAINDIR" #define GIT_ATTR_SOURCE_ENVIRONMENT "GIT_ATTR_SOURCE" +#define GIT_DEFAULT_HASH_ENVIRONMENT "GIT_DEFAULT_HASH" /* * Environment variable used in handshaking the wire protocol. diff --git a/repository.c b/repository.c index 15c10015b0..f912ee9a7c 100644 --- a/repository.c +++ b/repository.c @@ -1,5 +1,6 @@ #include "git-compat-util.h" #include "abspath.h" +#include "environment.h" #include "repository.h" #include "object-store-ll.h" #include "config.h" @@ -19,6 +20,27 @@ static struct repository the_repo; struct repository *the_repository = &the_repo; +static void set_default_hash_algo(struct repository *repo) +{ + const char *hash_name; + int algo; + + hash_name = getenv(GIT_DEFAULT_HASH_ENVIRONMENT); + if (!hash_name) + return; + algo = hash_algo_by_name(hash_name); + + /* + * NEEDSWORK: after all, falling back to SHA-1 by assigning + * GIT_HASH_SHA1 to algo here, instead of returning, may give + * us better behaviour. + */ + if (algo == GIT_HASH_UNKNOWN) + return; + + repo_set_hash_algo(repo, algo); +} + void initialize_repository(struct repository *repo) { repo->objects = raw_object_store_new(); @@ -26,6 +48,24 @@ void initialize_repository(struct repository *repo) repo->parsed_objects = parsed_object_pool_new(); ALLOC_ARRAY(repo->index, 1); index_state_init(repo->index, repo); + + /* + * When a command runs inside a repository, it learns what + * hash algorithm is in use from the repository, but some + * commands are designed to work outside a repository, yet + * they want to access the_hash_algo, if only for the length + * of the hashed value to see if their input looks like a + * plausible hash value. + * + * We are in the process of identifying the codepaths and + * giving them an appropriate default individually; any + * unconverted codepath that tries to access the_hash_algo + * will thus fail. The end-users however have an escape hatch + * to set GIT_DEFAULT_HASH environment variable to "sha1" get + * back the old behaviour of defaulting to SHA-1. + */ + if (repo == the_repository) + set_default_hash_algo(repo); } static void expand_base_dir(char **out, const char *in, diff --git a/setup.c b/setup.c index 7c996659bd..d084703465 100644 --- a/setup.c +++ b/setup.c @@ -1840,8 +1840,6 @@ int daemonize(void) #define TEST_FILEMODE 1 #endif -#define GIT_DEFAULT_HASH_ENVIRONMENT "GIT_DEFAULT_HASH" - static void copy_templates_1(struct strbuf *path, struct strbuf *template_path, DIR *dir) {