"blanet via GitGitGadget" <gitgitgadget@xxxxxxxxx> writes: > From: Xing Xin <xingxin.xx@xxxxxxxxxxxxx> > > When using the bundle-uri mechanism with a bundle list containing > multiple interrelated bundles, we encountered a bug where tips from > downloaded bundles were not discovered, thus resulting in rather slow > clones. This was particularly problematic when employing the heuristic > `creationTokens`. > > And this is easy to reproduce. Suppose we have a repository with a > single branch `main` pointing to commit `A`, firstly we create a base > bundle with > > git bundle create base.bundle main > > Then let's add a new commit `B` on top of `A`, so that an incremental > bundle for `main` can be created with > > git bundle create incr.bundle A..main > > Now we can generate a bundle list with the following content: > > [bundle] > version = 1 > mode = all > heuristic = creationToken > > [bundle "base"] > uri = base.bundle > creationToken = 1 > > [bundle "incr"] > uri = incr.bundle > creationToken = 2 > > A fresh clone with the bundle list above would give the expected > `refs/bundles/main` pointing at `B` in new repository, in other words we > already had everything locally from the bundles, but git would still > download everything from server as if we got nothing. > > So why the `refs/bundles/main` is not discovered? After some digging I > found that: > > 1. Bundles in bundle list are downloaded to local files via > `download_bundle_list` or via `fetch_bundles_by_token` for the > creationToken heuristic case. > 2. Then it tries to unbundle each bundle via `unbundle_from_file`, which > is called by `unbundle_all_bundles` or called within > `fetch_bundles_by_token` for the creationToken heuristic case. > 3. Here, we first read the bundle header to get all the prerequisites > for the bundle, this is done in `read_bundle_header`. > 4. Then we call `unbundle`, which calls `verify_bundle` to ensure that > the repository does indeed contain the prerequisites mentioned in the > bundle. > 5. The `verify_bundle` will call `parse_object`, within which the > `prepare_packed_git` or `reprepare_packed_git` is eventually called, > which means that the `raw_object_store->packed_git` data gets filled > in and ``packed_git_initialized` is set. This also means consecutive > calls to `prepare_packed_git` doesn't re-initiate > `raw_object_store->packed_git` since `packed_git_initialized` already > is set. > 6. If `unbundle` succeeds, it writes some refs via `refs_update_ref` > with `REF_SKIP_OID_VERIFICATION` set. So the bundle refs which can > target arbitrary objects are written to the repository. > 7. Finally in `do_fetch_pack_v2`, `mark_complete_and_common_ref` and > `mark_tips` are called with `OBJECT_INFO_QUICK` set to find local > tips. Here it won't call `reprepare_packed_git` anymore so it would > fail to parse oids that only reside in the last bundle. > > Back to the example above, when unbunding `incr.bundle`, `base.pack` is > enlisted to `packed_git` bacause of the prerequisites to verify. While s/bacause/because [snip] > diff --git a/bundle-uri.c b/bundle-uri.c > index 91b3319a5c1..65666a11d9c 100644 > --- a/bundle-uri.c > +++ b/bundle-uri.c > @@ -400,8 +400,7 @@ static int unbundle_from_file(struct repository *r, const char *file) > refs_update_ref(get_main_ref_store(the_repository), > "fetched bundle", bundle_ref.buf, oid, > has_old ? &old_oid : NULL, > - REF_SKIP_OID_VERIFICATION, > - UPDATE_REFS_MSG_ON_ERR); > + 0, UPDATE_REFS_MSG_ON_ERR); > } > > bundle_header_release(&header); > diff --git a/t/t5558-clone-bundle-uri.sh b/t/t5558-clone-bundle-uri.sh > index 1ca5f745e73..a5b04d6f187 100755 > --- a/t/t5558-clone-bundle-uri.sh > +++ b/t/t5558-clone-bundle-uri.sh > @@ -20,7 +20,10 @@ test_expect_success 'fail to clone from non-bundle file' ' > test_expect_success 'create bundle' ' > git init clone-from && > git -C clone-from checkout -b topic && > + > test_commit -C clone-from A && > + git -C clone-from bundle create A.bundle topic && > + > test_commit -C clone-from B && > git -C clone-from bundle create B.bundle topic > ' > @@ -259,6 +262,132 @@ test_expect_success 'clone bundle list (file, any mode, all failures)' ' > ! grep "refs/bundles/" refs > ' > > +######################################################################### > +# Clone negotiation related tests begin here > + > +test_expect_success 'negotiation: bundle with part of wanted commits' ' > + test_when_finished rm -rf trace*.txt && > + GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \ > + git clone --no-local --bundle-uri="clone-from/A.bundle" \ > + clone-from nego-bundle-part && > + git -C nego-bundle-part for-each-ref --format="%(refname)" >refs && > + grep "refs/bundles/" refs >actual && > + cat >expect <<-\EOF && > + refs/bundles/topic > + EOF > + test_cmp expect actual && > + # Ensure that refs/bundles/topic are sent as "have". > + grep "clone> have $(git -C clone-from rev-parse A)" trace-packet.txt > +' > + > +test_expect_success 'negotiation: bundle with all wanted commits' ' > + test_when_finished rm -rf trace*.txt && > + GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \ > + git clone --no-local --single-branch --branch=topic --no-tags \ > + --bundle-uri="clone-from/B.bundle" \ > + clone-from nego-bundle-all && > + git -C nego-bundle-all for-each-ref --format="%(refname)" >refs && > + grep "refs/bundles/" refs >actual && > + cat >expect <<-\EOF && > + refs/bundles/topic > + EOF > + test_cmp expect actual && > + # We already have all needed commits so no "want" needed. > + ! grep "clone> want " trace-packet.txt > +' > + > +test_expect_success 'negotiation: bundle list (no heuristic)' ' > + test_when_finished rm -f trace*.txt && > + cat >bundle-list <<-EOF && > + [bundle] > + version = 1 > + mode = all > + > + [bundle "bundle-1"] > + uri = file://$(pwd)/clone-from/bundle-1.bundle > + > + [bundle "bundle-2"] > + uri = file://$(pwd)/clone-from/bundle-2.bundle > + EOF > + > + GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \ > + git clone --no-local --bundle-uri="file://$(pwd)/bundle-list" \ > + clone-from nego-bundle-list-no-heuristic && > + > + git -C nego-bundle-list-no-heuristic for-each-ref --format="%(refname)" >refs && > + grep "refs/bundles/" refs >actual && > + cat >expect <<-\EOF && > + refs/bundles/base > + refs/bundles/left > + EOF > + test_cmp expect actual && > + grep "clone> have $(git -C nego-bundle-list-no-heuristic rev-parse refs/bundles/left)" trace-packet.txt > +' > + > +test_expect_success 'negotiation: bundle list (creationToken)' ' > + test_when_finished rm -f trace*.txt && > + cat >bundle-list <<-EOF && > + [bundle] > + version = 1 > + mode = all > + heuristic = creationToken > + > + [bundle "bundle-1"] > + uri = file://$(pwd)/clone-from/bundle-1.bundle > + creationToken = 1 > + > + [bundle "bundle-2"] > + uri = file://$(pwd)/clone-from/bundle-2.bundle > + creationToken = 2 > + EOF > + > + GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \ > + git clone --no-local --bundle-uri="file://$(pwd)/bundle-list" \ > + clone-from nego-bundle-list-heuristic && > + > + git -C nego-bundle-list-heuristic for-each-ref --format="%(refname)" >refs && > + grep "refs/bundles/" refs >actual && > + cat >expect <<-\EOF && > + refs/bundles/base > + refs/bundles/left > + EOF > + test_cmp expect actual && > + grep "clone> have $(git -C nego-bundle-list-heuristic rev-parse refs/bundles/left)" trace-packet.txt > +' > + > +test_expect_success 'negotiation: bundle list with all wanted commits' ' > + test_when_finished rm -f trace*.txt && > + cat >bundle-list <<-EOF && > + [bundle] > + version = 1 > + mode = all > + heuristic = creationToken > + > + [bundle "bundle-1"] > + uri = file://$(pwd)/clone-from/bundle-1.bundle > + creationToken = 1 > + > + [bundle "bundle-2"] > + uri = file://$(pwd)/clone-from/bundle-2.bundle > + creationToken = 2 > + EOF > + > + GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \ > + git clone --no-local --single-branch --branch=left --no-tags \ > + --bundle-uri="file://$(pwd)/bundle-list" \ > + clone-from nego-bundle-list-all && > + > + git -C nego-bundle-list-all for-each-ref --format="%(refname)" >refs && > + grep "refs/bundles/" refs >actual && > + cat >expect <<-\EOF && > + refs/bundles/base > + refs/bundles/left > + EOF > + test_cmp expect actual && > + # We already have all needed commits so no "want" needed. > + ! grep "clone> want " trace-packet.txt > +' > + > ######################################################################### > # HTTP tests begin here > > > base-commit: d8ab1d464d07baa30e5a180eb33b3f9aa5c93adf > -- > gitgitgadget This update looks good to me, Thanks.
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