Derrick Stolee <stolee@xxxxxxxxx> writes: > On 8/14/2020 3:25 PM, Junio C Hamano wrote: >> "Derrick Stolee via GitGitGadget" <gitgitgadget@xxxxxxxxx> writes: >> >>> As discussed [1], there is some concern around binary file formats requiring >>> the context of the repository config in order to infer hash lengths. Two >>> formats that were designed with the hash transition in mind (commit-graph >>> and multi-pack-index) have bytes available to indicate the hash algorithm >>> used. Let's actually update these formats to be more self-contained with the >>> two hash algorithms being available. >>> ... >>> If this is the way we want to go with the formats, then I'll assist >>> coordinating these textual and semantic merge conflicts. >> >> I agree that the files should be self-identifying, but have these >> changes tested without sha256 hash? > > All of the test scripts pass with and without GIT_TEST_DEFAULT_HASH=sha256, > and this test in t5318 (and a similar one in t5319) are explicit about > testing both options: > > +test_expect_success 'warn on improper hash version' ' > + git init --object-format=sha1 sha1 && > + ( > + cd sha1 && > + test_commit 1 && > + git commit-graph write --reachable && > + mv .git/objects/info/commit-graph ../cg-sha1 > + ) && > + git init --object-format=sha256 sha256 && > + ( > + cd sha256 && > + test_commit 1 && > + git commit-graph write --reachable && > + mv .git/objects/info/commit-graph ../cg-sha256 > + ) && > + ( > + cd sha1 && > + mv ../cg-sha256 .git/objects/info/commit-graph && > + git log -1 2>err && > + test_i18ngrep "commit-graph hash version 2 does not match version 1" err > + ) && > + ( > + cd sha256 && > + mv ../cg-sha1 .git/objects/info/commit-graph && > + git log -1 2>err && > + test_i18ngrep "commit-graph hash version 1 does not match version 2" err > + ) > +' > + > > Since this tests exactly that the "hash version" byte is the same in > a SHA-1 repo, this checks that the new version of Git writes backwards- > compatible data in SHA-1 repos. > > Or are you hinting at a more subtle test scenario that I missed? No, I was just wondering how ready we are, as the four tests looked too easy ;-)
