@matheusbsbs / matheus-bagliano / commits / 800e6a7041

t3404: prepare 'short SHA-1 collision' tests for SHA-256

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. 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 <johannes.schindelin@gmx.de> Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Reviewed-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Johannes Schindelin committed Jul 29, 2020 at 23:13 UTC 800e6a7041961b91fb97ab5dfd440983953fe75c

1 file changed +40 -9

t/t3404-rebase-interactive.sh

+40 -9

index 4a7d21f898..9744e88760 100755 --- a/t/t3404-rebase-interactive.sh +++ b/t/t3404-rebase-interactive.sh @@ -1250,7 +1250,7 @@ test_expect_success 'rebase -i error on commits with \ in message' ' test_expect_code 1 grep " emp" error ' -test_expect_success SHA1 'short SHA-1 setup' ' +test_expect_success 'short commit ID setup' ' test_when_finished "git checkout master" && git checkout --orphan collide && git rm -rf . && @@ -1262,23 +1262,54 @@ test_expect_success SHA1 'short SHA-1 setup' ' ) ' -test_expect_success SHA1 'short SHA-1 collide' ' +if test -n "$GIT_TEST_FIND_COLLIDER" +then + author="$(unset test_tick; test_tick; git var GIT_AUTHOR_IDENT)" + committer="$(unset test_tick; test_tick; git var GIT_COMMITTER_IDENT)" + blob="$(git rev-parse collide2:collide)" + from="$(git rev-parse collide1^0)" + repl="commit refs/heads/collider-&\\n" + repl="${repl}author $author\\ncommitter $committer\\n" + repl="${repl}data <<EOF\\ncollide2 &\\nEOF\\n" + repl="${repl}from $from\\nM 100644 $blob collide\\n" + test_seq 1 32768 | sed "s|.*|$repl|" >script && + git fast-import <script && + git pack-refs && + git for-each-ref >refs && + grep "^$(test_oid t3404_collision)" <refs >matches && + cat matches && + test_line_count -gt 2 matches || { + echo "Could not find a collider" >&2 + exit 1 + } +fi + +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 test_when_finished "reset_rebase && git checkout master" && git checkout collide && - colliding_sha1=6bcda37 && - test $colliding_sha1 = "$(git rev-parse HEAD | cut -c 1-7)" && + colliding_id=$(test_oid t3404_collision) && + hexsz=$(test_oid hexsz) && + test $colliding_id = "$(git rev-parse HEAD | cut -c 1-4)" && + test_config core.abbrev 4 && ( unset test_tick && test_tick && set_fake_editor && - FAKE_COMMIT_MESSAGE="collide2 ac4f2ee" \ + FAKE_COMMIT_MESSAGE="collide2 $(test_oid t3404_collider)" \ FAKE_LINES="reword 1 break 2" git rebase -i HEAD~2 && - test $colliding_sha1 = "$(git rev-parse HEAD | cut -c 1-7)" && - grep "^pick $colliding_sha1 " \ + test $colliding_id = "$(git rev-parse HEAD | cut -c 1-4)" && + grep "^pick $colliding_id " \ .git/rebase-merge/git-rebase-todo.tmp && - grep "^pick [0-9a-f]\{40\}" \ + grep "^pick [0-9a-f]\{$hexsz\}" \ .git/rebase-merge/git-rebase-todo && - grep "^pick [0-9a-f]\{40\}" \ + grep "^pick [0-9a-f]\{$hexsz\}" \ .git/rebase-merge/git-rebase-todo.backup && git rebase --continue ) &&