Re: [PATCH v4 04/39] t3404: prepare 'short SHA-1 collision' tests for SHA-256
From: Eric Sunshine <hidden>
Date: 2020-07-26 22:31:52
On Sun, Jul 26, 2020 at 3:55 PM brian m. carlson [off-list ref] wrote:
The idea of the magic value "ac4f2ee" in this test is to make the reworded commit `collide2` have the same shortened ID as the commit `collide3`. To port the same idea to the SHA-256 version of Git, we therefore need another magic value that causes the same collision, but this time with the SHA-256 version of the commit IDs. In this patch, we add code guarded by `GIT_TEST_FIND_COLLIDER` to do exactly that. Essentially, a large number of integers is appended to the commit message "collide2" to find such a collision. To make it easier to find such a collision, we reduce the number of digits to 4. The `t/oid-info/oid` file now lists the values found in that way, and the test cases are modified to use those values.
This seems to be saying that t/oid-info/oid has been updated to contain the colliding OID's generated for this test, however, those OID's are actually specified inline in the test itself (which is the appropriate place for them since they are specific to this test). So, this paragraph/sentence probably ought to be dropped.
quoted hunk ↗ jump to hunk
As the tests are no longer dependent on SHA-1, we also rename their titles to talk about "commit IDs" instead of "SHA-1s". Signed-off-by: Johannes Schindelin <redacted> Signed-off-by: brian m. carlson <redacted> ---diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh@@ -1262,23 +1263,54 @@ test_expect_success SHA1 'short SHA-1 setup' ' +test_expect_success 'short commit ID collide' ' + test_oid_cache <<-EOF && + # collision-related constants + t3404_collision sha1:6bcd + t3404_collision sha256:0161 + t3404_collider sha1:ac4f2ee + t3404_collider sha256:16697 + EOF