On Wed, Mar 13 2019, Johannes Schindelin via GitGitGadget wrote:
> From: Johannes Schindelin <johannes.schindelin@xxxxxx>
>
> We specifically support `exec` commands in `git rebase -i`'s todo lists
> to rewrite the very same todo list. Of course, we need to validate that
> todo list when re-reading it.
>
> It is also totally legitimate to extend the todo list by `pick` lines
> using short names of commits that were created only after the rebase
> started.
>
> And this is where the loose object cache interferes with this feature:
> if *some* loose object was read whose hash shares the same first two
> digits with a commit that was not yet created when that loose object was
> created, then we fail to find that new commit by its short name in
> `get_oid()`, and the interactive rebase fails with an obscure error
> message like:
>
> error: invalid line 1: pick 6568fef
> error: please fix this using 'git rebase --edit-todo'.
As a further improvement, is there a good reason for why we wouldn't
pass something down to the oid machinery to say "we're only interested
in commits". I have a WIP series somewhere to generalize that more, but
e.g. here locally:
$ git rev-parse 80b06
error: short SHA1 80b06 is ambiguous
hint: The candidates are:
hint: 80b06b942e commit 2019-03-13 - Revert "this patch fail whales"
hint: 80b063bb9b blob
hint: 80b06f0714 blob
80b06
$ git rev-parse 80b06^{commit}
80b06b942ed33e597a0152b3e6ba45b7d8ead94b
I can't remember if there's some caveat with that particular peel syntax
I meant to fix, but I mean if we could pass something down to say "no
blobs or trees" shouldn't we?
Then stuff like this wouldn't die:
$ git rebase -i
hint: Waiting for your editor to close the file... Waiting for Emacs...
error: short SHA1 80b06 is ambiguous
hint: The candidates are:
hint: 80b06b942e commit 2019-03-13 - Revert "this patch fail whales"
hint: 80b063bb9b blob
hint: 80b06f0714 blob
error: invalid line 2: p 80b06 Revert "this patch fail whales"
You can fix this with 'git rebase --edit-todo' and then run 'git rebase --continue'.
> [...]
> +test_expect_failure SHA1 'loose object cache vs re-reading todo list' '
> + GIT_REBASE_TODO=.git/rebase-merge/git-rebase-todo &&
> + export GIT_REBASE_TODO &&
> + write_script append-todo.sh <<-\EOS &&
> + # For values 5 and 6, this yields SHA-1s with the same first two digits
> + echo "pick $(git rev-parse --short \
> + $(printf "%s\\n" \
> + "tree $EMPTY_TREE" \
> + "author A U Thor <author@xxxxxxxxxxx> $1 +0000" \
> + "committer A U Thor <author@xxxxxxxxxxx> $1 +0000" \
> + "" \
> + "$1" |
> + git hash-object -t commit -w --stdin))" >>$GIT_REBASE_TODO
> +
> + shift
> + test -z "$*" ||
> + echo "exec $0 $*" >>$GIT_REBASE_TODO
> + EOS
> +
> + git rebase HEAD -x "./append-todo.sh 5 6"
> +'
> +
> test_done
This is a test for rebase, but perhaps it would be best put in
t1512-rev-parse-disambiguation.sh. Then when we finally port that
somehow to SHA256 we'll have all this SHA-1 golfing in the same file &
can fix it at once. Just a thought...
