@matheusbsbs / matheus-bagliano / commits / 66ae9a57b8

t3404: rebase -i: demonstrate short SHA-1 collision

The 'todo' sheet for interactive rebase shows abbreviated SHA-1's and then performs its operations upon those shortened values. This can lead to an abort if the SHA-1 of a reworded or edited commit is no longer unique within the abbreviated SHA-1 space and a subsequent SHA-1 in the todo list has the same abbreviated value. For example: edit f00dfad first pick badbeef second If, after editing, the new SHA-1 of "first" also has prefix badbeef, then the subsequent 'pick badbeef second' will fail since badbeef is no longer a unique SHA-1 abbreviation: error: short SHA1 badbeef is ambiguous. fatal: Needed a single revision Invalid commit name: badbeef Demonstrate this problem with a couple of specially crafted commits which initially have distinct abbreviated SHA-1's, but for which the abbreviated SHA-1's collide after a simple rewording of the first commit's message. Signed-off-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Eric Sunshine committed Aug 23, 2013 at 20:10 UTC 66ae9a57b887fce227b566b32bd47d2c37ada461

1 file changed +24

t/t3404-rebase-interactive.sh

+24

@@ -1037,4 +1037,28 @@ test_expect_success 'rebase -i with --strategy and -X' '

1037 test $(cat file1) = Z

1038 '

1039

1040 +test_expect_success 'short SHA-1 setup' '

1041 + test_when_finished "git checkout master" &&

1042 + git checkout --orphan collide &&

1043 + git rm -rf . &&

1044 + (

1045 + unset test_tick &&

1046 + test_commit collide1 collide &&

1047 + test_commit --notick collide2 collide &&

1048 + test_commit --notick collide3 collide

1049 + )

1050 +'

1051 +

1052 +test_expect_failure 'short SHA-1 collide' '

1053 + test_when_finished "reset_rebase && git checkout master" &&

1054 + git checkout collide &&

1055 + (

1056 + unset test_tick &&

1057 + test_tick &&

1058 + set_fake_editor &&

1059 + FAKE_COMMIT_MESSAGE="collide2 ac4f2ee" \

1060 + FAKE_LINES="reword 1 2" git rebase -i HEAD~2

1061 + )

1062 +'

1063 +

1064 test_done