On Mon, Oct 07, 2019 at 11:18:25AM -0700, Jonathan Tan wrote: > When running "git fetch" in a partial clone with no blobs, for example, > by: > > git clone --filter=blob:none --no-checkout \ > https://kernel.googlesource.com/pub/scm/git/git > git -C git fetch > > "git fetch" will fail to load the config blob object, printing "unable > to load config blob object". I'm having some trouble figuring out which object is actually missing. Is this the .git/config object? (That doesn't make much sense to me...) Is it .gitmodules? > > This is because fetch_if_missing is set to 0 before the config is > processed. Git must set fetch_if_missing to 0 before the fetch because > as part of the fetch, packfile negotiation happens (and we do not want > to fetch any missing objects when checking existence of objects), but we > do not need to set it so early. Move the setting of fetch_if_missing to > the earliest possible point in cmd_fetch(), right before any fetching > happens. Doubts aside about what's actually failing, I definitely agree with the premise of not setting this until the last moment we need it. Plus, I may be alone here, but it'd make it easier for me to understand the code if I saw a note explaining *why* we don't want to fetch_if_missing in this case. By the way, I think I understand that this is OK to go in unconditionally because: - In the full clone case, it's a no-op; we haven't got anything that's missing, so who cares. - In the filter case, it's as you said - we don't want to fetch_if_missing because that will turn someone's partial clone into a a full clone. - This probably applies to bare checkout, too. Of course if I'm wrong I'd like to know, but that's how I understand it at the moment. > --- > This is not a full solution, but this helps in the use case described in > the commit message. The full solution probably will involve teaching the > fetch mechanism to support arbitrary struct repository objects, and by > moving fetch_if_missing into the repository object. (Alternatively, we > could add the equivalent of OBJECT_INFO_SKIP_FETCH_OBJECT to functions > like parse_commit() that are used by files like negotiator/default.c, or > split up commit parsing into object reading - which already has that > flag - and commit parsing.) Ah, I remember this was listed as one of the potential intern projects - I think we dismissed it as being too tech-debt-y for an intern to feel good about. :( > --- > builtin/fetch.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/builtin/fetch.c b/builtin/fetch.c > index 24d382b2fb..865ae6677d 100644 > --- a/builtin/fetch.c > +++ b/builtin/fetch.c > @@ -1666,8 +1666,6 @@ int cmd_fetch(int argc, const char **argv, const char *prefix) > > packet_trace_identity("fetch"); > > - fetch_if_missing = 0; > - > /* Record the command line for the reflog */ > strbuf_addstr(&default_rla, "fetch"); > for (i = 1; i < argc; i++) > @@ -1734,6 +1732,8 @@ int cmd_fetch(int argc, const char **argv, const char *prefix) > } > } > > + fetch_if_missing = 0; > + > if (remote) { > if (filter_options.choice || has_promisor_remote()) > fetch_one_setup_partial(remote); > -- > 2.23.0.581.g78d2f28ef7-goog > The diff, though, looks fine for me. - Emily
