On Tue, Aug 10, 2021 at 8:58 PM Elijah Newren <newren@xxxxxxxxx> wrote: > > On Tue, Aug 10, 2021 at 8:51 AM anatoly techtonik <techtonik@xxxxxxxxx> wrote: > > > > On Mon, Aug 9, 2021 at 9:15 PM Elijah Newren <newren@xxxxxxxxx> wrote: > > > > > [2] https://lore.kernel.org/git/CABPp-BH4dcsW52immJpTjgY5LjaVfKrY9MaUOnKT3byi2tBPpg@xxxxxxxxxxxxxx/ > > Signed commits is just one issue, and you'll have to add special code > to handle a bunch of other special cases if you go down this route. > I'd rephrase the problem. You want to know when _your tool_ (e.g. > reposurgeon since you refer to it multiple times; I'm guessing you're > contributing to it?) has not modified a commit or any of its > ancestors, and when it hasn't, then _your tool_ should remove that > commit from the fast-export stream and replace any references to it by > the original commit's object id. I outlined how to do this in [2], > referenced above, making use of the --show-original-ids flag to > fast-export. If you do that, then for any commits which you haven't > modified (including not modifying any of its ancestors), then you'll > keep the same commits as-is with no stripping of gpg-signatures or > canonicalization of objects, so that you'll have the exact same commit > IDs. Further, you can do this today, without any changes to git > fast-export or git fast-import. Took me a while to process the reply. Let's recap. I want to make a roundtrip export/import of https://github.com/simons-public/protonfixes which should get exactly the same repository. # --- fast-export to exported.txt git clone https://github.com/simons-public/protonfixes git -C protonfixes fast-export --all > exported.txt # --- check revision of the repo git -C protonfixes rev-parse HEAD # 681411ba8ceb5d2d790e674eb7a5b98951d426e6 # --- fast-import into new repo git init newrepo git -C newrepo fast-import < exported.txt # --- checking revision of the new repo git -C newrepo rev-parse HEAD # 9888762d7857d9721f0c354e7fc187a199754a4b Hashes don't match. The roundtrip fails. Let's see if --reference-excluded-parents helps. # --- export below produces the same export stream as above git -C protonfixes fast-export --reference-excluded-parents --all > exported_parents.txt Because fast-import/fast-export don't work, you propose to keep the old repo around until it is clear which commits I am going to modify. Then make a new fast-export starting from the first commit I am going to modify with --reference-excluded-parents flag. Is that correct so far? Then given this partial export and old repo, how to init the new repo that fast-import can apply its tail there? What if I have multiple commits that I modify, but I don't know which of their parents was first? And when I touch commits from different branches, how to recreate their parent history intact in one repo? -- anatoly t.
