Re: [PATCH v3 1/1] upload-pack.c: fix filter spec quoting bug

>
>
> On Tue, Jan 26 2021, Jacob Vosmaer wrote:
>
> > This fixes a bug that occurs when you combine partial clone and
> > uploadpack.packobjectshook. You can reproduce it as follows:
>
> Let's:
>
>  * Refer to the commit we're fixing a bug in, i.e. Junio's mention of
>    10ac85c7 (upload-pack: add object filtering for partial clone,
>    2017-12-08) upthread.
>
>  * See also "imperative-mood" in SubmittingPatches. I.e. say "Fix a bug
>    in ..." not "This fixes ... can be reproduced as"
>
>  * uploadpack.packObjectsHook not uploadpack.packobjectshook except in C
>    code.
>
> > git clone -u 'git -c uploadpack.allowfilter '\
> > '-c uploadpack.packobjectshook=env '\
> > 'upload-pack' --filter=blob:none --no-local \
> > src.git dst.git
>
> This and the output below would be more readable indented.
>
> > Be careful with the line endings because this has a long quoted string
> > as the -u argument.
> >
> > The error I get when I run this is:
> >
> > Cloning into '/tmp/broken'...
> > remote: fatal: invalid filter-spec ''blob:none''
> > error: git upload-pack: git-pack-objects died with error.
> > fatal: git upload-pack: aborting due to possible repository corruption on the remote side.
> > remote: aborting due to possible repository corruption on the remote side.
> > fatal: early EOF
> > fatal: index-pack failed
>
> [...]
>
> > The problem is an unnecessary and harmful layer of quoting. I tried
> > digging through the history of this function and I think this quoting
> > was there from the start.
>
>
> ...So looked at "git log" but didn't try to check out 10ac85c7 and see
> if it had the same issue? If we're going to leave a note about this at
> all probably better to help future source spelunkers by being able to
> say the issue was there from the start.
>
>
> > My best guess is that it stems from a
> > misunderstanding what use_shell=1 means. The code seems to assume it
> > means "arguments get joined into one big string, then fed to /bin/sh".
> > But that is not what it means: use_shell=1 means that the first
> > argument in the arguments array may be a shell script and if so should
> > be passed to /bin/sh. All other arguments are passed as normal
> > arguments.
> >
> > The solution is simple: never quote the filter spec.
> >
> > This commit removes the conditional quoting and adds a test for
> > partial clone in t5544.
> >
>
> Thanks for hacking this up! Hopefully the above is helpful and not too
> nitpicky. Mainly wanted to help you get future patches through more
> easily...
>
> > Signed-off-by: Jacob Vosmaer <jacob@gitlab.com>
> > ---
> >  t/t5544-pack-objects-hook.sh | 9 +++++++++
> >  upload-pack.c                | 9 +--------
> >  2 files changed, 10 insertions(+), 8 deletions(-)
> >
> > diff --git a/t/t5544-pack-objects-hook.sh b/t/t5544-pack-objects-hook.sh
> > index 4357af1525..f5ba663d64 100755
> > --- a/t/t5544-pack-objects-hook.sh
> > +++ b/t/t5544-pack-objects-hook.sh
> > @@ -59,4 +59,13 @@ test_expect_success 'hook does not run from repo config' '
> >       test_path_is_missing .git/hook.stdout
> >  '
> >
> > +test_expect_success 'hook works with partial clone' '
> > +     clear_hook_results &&
> > +     test_config_global uploadpack.packObjectsHook ./hook &&
> > +     test_config_global uploadpack.allowFilter true &&
> > +     git clone --bare --no-local --filter=blob:none . dst.git &&
> > +     git -C dst.git rev-list --objects --missing=print HEAD >objects &&
> > +     grep "^?" objects
> > +'
> > +
> >  test_done
> > diff --git a/upload-pack.c b/upload-pack.c
> > index 3b66bf92ba..eae1fdbc55 100644
> > --- a/upload-pack.c
> > +++ b/upload-pack.c
> > @@ -305,14 +305,7 @@ static void create_pack_file(struct upload_pack_data *pack_data,
> >       if (pack_data->filter_options.choice) {
> >               const char *spec =
> >                       expand_list_objects_filter_spec(&pack_data->filter_options);
> > -             if (pack_objects.use_shell) {
> > -                     struct strbuf buf = STRBUF_INIT;
> > -                     sq_quote_buf(&buf, spec);
> > -                     strvec_pushf(&pack_objects.args, "--filter=%s", buf.buf);
> > -                     strbuf_release(&buf);
> > -             } else {
> > -                     strvec_pushf(&pack_objects.args, "--filter=%s", spec);
> > -             }
> > +             strvec_pushf(&pack_objects.args, "--filter=%s", spec);
> >       }
> >       if (uri_protocols) {
> >               for (i = 0; i < uri_protocols->nr; i++)
>