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[92.33.153.30]) by smtp.gmail.com with ESMTPSA id o2sm1847407lfi.50.2020.08.14.05.22.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Aug 2020 05:22:11 -0700 (PDT) From: =?utf-8?q?Martin_=C3=85gren?= To: "brian m. carlson" Cc: git@vger.kernel.org, Derrick Stolee , Junio C Hamano Subject: [PATCH 5/5] commit-graph-format.txt: fix "Hash Version" description Date: Fri, 14 Aug 2020 14:21:46 +0200 Message-Id: X-Mailer: git-send-email 2.28.0.277.g9b3c35fffd In-Reply-To: References: <20200813224901.2652387-1-sandals@crustytoothpaste.net> MIME-Version: 1.0 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org We say that value 1 means "SHA-1", but in fact, it means "whatever the_hash_algo is", see commit c166599862 ("commit-graph: convert to using the_hash_algo", 2018-11-14). Signed-off-by: Martin Ågren --- If we want to be more fine-grained in the future, we'll need to say, e.g., "2 means SHA-1, 3 means SHA-256" or, perhaps preferrably, bump the version number. I wonder: Should we instead say "1 means SHA-1, 2 means SHA-256"? It could be implemented as "easily" as "if (value_from_header != value_from_the_hash_algo) die(...);" for now. Might that pay off in the long run? This relates to Stolee's "in a vacuum" comment [1] ... so maybe we're fine. [1] https://lore.kernel.org/git/da077fb0-14bb-b84f-c526-d759ebc9f5eb@gmail.com/ Documentation/technical/commit-graph-format.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/technical/commit-graph-format.txt index 440541045d..3535426d32 100644 --- a/Documentation/technical/commit-graph-format.txt +++ b/Documentation/technical/commit-graph-format.txt @@ -42,8 +42,8 @@ HEADER: 1-byte version number: Currently, the only valid version is 1. - 1-byte Hash Version (1 = SHA-1) - We infer the hash length (H) from this value. + 1-byte Hash Version (1 = SHA-1 in SHA-1 repo, SHA-256 in SHA-256 repo) + We infer the hash length (H) from the hash algo derived from this value. 1-byte number (C) of "chunks"