On Tue, Jul 12 2022, Han Xin wrote: > The commit-graph is used to opportunistically optimize accesses to > certain pieces of information on commit objects, and > lookup_commit_in_graph() tries to say "no" when the requested commit > does not locally exist by returning NULL, in which case the caller > can ask for (which may result in on-demand fetching from a promisor > remote) and parse the commit object itself. > > However, it uses a wrong helper, repo_has_object_file(), to do so. > This helper not only checks if an object is mmediately available in > the local object store, but also tries to fetch from a promisor remote. > But the fetch machinery calls lookup_commit_in_graph(), thus causing an > infinite loop. > > We should make lookup_commit_in_graph() expect that a commit given to it > can be legitimately missing from the local object store, by using the > has_object_file() helper instead. > > Signed-off-by: Han Xin <hanxin.hx@xxxxxxxxxxxxx> > --- > commit-graph.c | 2 +- > t/t5330-no-lazy-fetch-with-commit-graph.sh | 47 ++++++++++++++++++++++ > 2 files changed, 48 insertions(+), 1 deletion(-) > create mode 100755 t/t5330-no-lazy-fetch-with-commit-graph.sh > > diff --git a/commit-graph.c b/commit-graph.c > index 92d4503336..2b04ef072d 100644 > --- a/commit-graph.c > +++ b/commit-graph.c > @@ -898,7 +898,7 @@ struct commit *lookup_commit_in_graph(struct repository *repo, const struct obje > return NULL; > if (!search_commit_pos_in_graph(id, repo->objects->commit_graph, &pos)) > return NULL; > - if (!repo_has_object_file(repo, id)) > + if (!has_object(repo, id, 0)) > return NULL; > > commit = lookup_commit(repo, id); > diff --git a/t/t5330-no-lazy-fetch-with-commit-graph.sh b/t/t5330-no-lazy-fetch-with-commit-graph.sh > new file mode 100755 > index 0000000000..2cc7fd7a47 > --- /dev/null > +++ b/t/t5330-no-lazy-fetch-with-commit-graph.sh > @@ -0,0 +1,47 @@ > +#!/bin/sh > + > +test_description='test for no lazy fetch with the commit-graph' > + > +. ./test-lib.sh > + > +test_expect_success 'setup: prepare a repository with a commit' ' > + git init with-commit && > + test_commit -C with-commit the-commit && > + oid=$(git -C with-commit rev-parse HEAD) > +' > + > +test_expect_success 'setup: prepare a repository with commit-graph contains the commit' ' > + git init with-commit-graph && > + echo "$(pwd)/with-commit/.git/objects" \ > + >with-commit-graph/.git/objects/info/alternates && > + # create a ref that points to the commit in alternates > + git -C with-commit-graph update-ref refs/ref_to_the_commit "$oid" && > + # prepare some other objects to commit-graph > + test_commit -C with-commit-graph something && > + git -c gc.writeCommitGraph=true -C with-commit-graph gc && > + test_path_is_file with-commit-graph/.git/objects/info/commit-graph > +' > + > +test_expect_success 'setup: change the alternates to what without the commit' ' > + git init --bare without-commit && > + git -C with-commit-graph cat-file -e $oid && > + echo "$(pwd)/without-commit/objects" \ > + >with-commit-graph/.git/objects/info/alternates && > + test_must_fail git -C with-commit-graph cat-file -e $oid > +' > + > +test_expect_success 'fetch any commit from promisor with the usage of the commit graph' ' > + # setup promisor and prepare any commit to fetch > + git -C with-commit-graph remote add origin "$(pwd)/with-commit" && > + git -C with-commit-graph config remote.origin.promisor true && > + git -C with-commit-graph config remote.origin.partialclonefilter blob:none && > + test_commit -C with-commit any-commit && > + anycommit=$(git -C with-commit rev-parse HEAD) && > + GIT_TRACE="$(pwd)/trace.txt" \ > + git -C with-commit-graph fetch origin $anycommit 2>err && > + ! grep "fatal: promisor-remote: unable to fork off fetch subprocess" err && This part seems quite odd, we tested the exit code, so here we're being paranoid about not getting a specific "fatal" error message. It seems more worthwhile to test the warnings we emit, which in this case seem to be duplicated (but that's probably an existing issue...). > + grep "git fetch origin" trace.txt >actual && > + test_line_count = 1 actual > +' I wondered if "test_subcomand" here would be better, i.e. fewer things scraping GIT_TRACE, and using the machine-readable GIT_TRACE2_EVENT instead...
