On Sat, May 20, 2017 at 1:13 PM, Junio C Hamano <gitster@xxxxxxxxx> wrote: > Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> writes: > >> Replace the forked sha1dc directory with a copy of the upstream code >> imported as a submodule. This is the exact same code as now exists in >> the sha1dc/ directory. >> >> The initial reason for copy/pasting the code into sha1dc and locally >> modifying it was that it needed to be altered to work with the git >> project. >> >> The upstream project has accepted my code changes to allow us to use >> their code as-is, see the preceding commit for details. So import the >> code as a submodule instead, this will make it easier to keep >> up-to-date with any upstream fixes or improvements. >> >> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> >> --- >> .gitmodules | 4 ++++ >> Makefile | 4 ++-- >> hash.h | 2 +- >> sha1collisiondetection | 1 + >> 4 files changed, 8 insertions(+), 3 deletions(-) >> create mode 100644 .gitmodules >> create mode 160000 sha1collisiondetection > > I am not sure how prepared our .travis.yml is to deal with a > submodule, I'd prefer to have this step broken down to two step > process. > > That is, [PATCH 2.1/3] first adds an otherwise unused submodule, so > that people can optionally do "git submodule init && git submodule > update" so that they can compare the contents of sha1dc/ that has > been updated by [PATCH 1/3] with the up-to-date upstream. Then > [PATCH 2.2/3] would update the Makefile and hash.h to use the code > in the submodule. > > I actually would want to see us proceed even more cautiously---if > the latter-half, i.e. [PATCH 2.2/3], is arranged so that it uses the > new sha1collisiondetection/ only when the submodule is initialized > and populated, and otherwise it uses sha1dc/ as before, I would feel > a lot safer. I wouldn't be this paranoid if this "let's start using > submodule ourselves" were done to some optional corner (like compat/ > or contrib/ somewhere), but this is the default hash function. I do > want to have something like this to force us (and submodule folks) > to get any kinks out, but I do not want to see many people not even > be able to build while this new arrangement is eased in. Once > people are comfortable with the new arrangement to use code from > submodule, we can then take [PATCH 3/3] to remove the old sha1dc/ > directory and the migration will be complete. Makes sense to take it slow. Hopefully this addresses your comments. I dropped the 3rd patch to remove sha1dc/ and the 2nd patch adds sha1collisiondetection/ as submodule, but it's not used unless you specify DC_SHA1_SUBMODULE in addition to DC_SHA1. Both patches should be safe to include & not cause any disruption, but now those interested in making the submodule experience in git.git better can init/update & set DC_SHA1_SUBMODULE=Y to play with it. Note that both patches update to a newer version of the upstream code. I sent them another pull request with some cleanups, one of which is to ignore .depends in their .gitignore file. > I also am not very happy with .gitmodules pointing at a single point > of failure. It would be nice if you can arrange a couple of mirrors > and have a comment in .gitmodules file to tell folks that they can > use these alternates by insteadOf or some other mechanism. I liked the suggestion to make the URL a relative path, but this would require you to maintain a mirror in the same places you push git.git to, is that something you'd be willing to do? For now having no-mirror isn't a big issue with my new 2/2 since it'se something you have to opt-in to with a build flag, which I suspect only I/Brandon/Stefan & a few others will use. Ævar Arnfjörð Bjarmason (2): sha1dc: update from upstream sha1dc: optionally use sha1collisiondetection as a submodule .gitmodules | 4 +++ Makefile | 21 +++++++++++- hash.h | 4 +++ sha1collisiondetection | 1 + sha1dc/sha1.c | 91 +++++++++++++++++++++++++++++++++----------------- sha1dc/sha1.h | 90 ++++++++++++++++++++++--------------------------- sha1dc/ubc_check.c | 13 ++++++-- sha1dc/ubc_check.h | 14 ++++++-- sha1dc_git.c | 24 +++++++++++++ sha1dc_git.h | 19 +++++++++++ 10 files changed, 193 insertions(+), 88 deletions(-) create mode 100644 .gitmodules create mode 160000 sha1collisiondetection create mode 100644 sha1dc_git.c create mode 100644 sha1dc_git.h -- 2.13.0.303.g4ebf302169