Re: [PATCH] fetch-pack: demonstrate --all failure when remote is empty
On Wed, Jun 13, 2018 at 10:13:07AM -0700, Junio C Hamano wrote: > Kirill Smelkov writes: > > > ( Junio, please pick up the patch provided in the end ) > > > > On Tue, Jun 12, 2018 at 06:54:17PM +, Kirill Smelkov wrote: > >> On Tue, Jun 12, 2018 at 05:48:49AM -0400, Jeff King wrote: > >> > On Mon, Jun 11, 2018 at 09:43:02AM +, Kirill Smelkov wrote: > > [...] > > > >> > > I'm not sure, but I would say that `fetch-pack --all` from an empty > >> > > repository should not fail and should just give empty output as fetch > >> > > does. > >> > > >> > Yeah, that seems reasonable to me. The die() that catches this dates > >> > back to 2005-era, and we later taught the "fetch" porcelain to handle > >> > this. I don't _think_ anybody would be upset that the plumbing learned > >> > to treat this as a noop. It's probably a one-liner change in > >> > fetch_pack() to return early instead of dying. > > I actually have a slight preference to the current "attempting to > fetch from a total emptiness is so rare that it is worth grabbing > attention of whoever does so" behaviour, to be honest. I see. > Oh, wait, is this specific to "fetch-pack" and the behaviour of > end-user-facing "git fetch" is kept same as before? If then, I'd be > somewhat sympathetic to the cause---it would be more convenient for > the calling Porcelain script if this turned into a silent noop (even > though it would probably make it harder to diagnose when such a > Porcelain is set up incorrectly e.g. pointing at an empty repository > that is not the one the Porcelain writer intended to fetch from). Yes, it is only for fetch-pack, and behaviour of porcelain fetch is kept as it was before. > > However with transport.c being there too, since I'm no longer using > > `fetch-pack --all`, now it is best for me to not delve into this story > > and just stop with attached patch. > > If we do not plan to change the behaviour later ourselves, I do not > think it makes sense, nor it is fair to those future developers who > inherit this project, to declare that the established behaviour is > wrong with an 'expect-failure' test like this, to be honest. I see. Let's please cancel this patch then. > > +test_expect_failure 'test --all wrt empty.git' ' > > + git init --bare empty.git && > > + ( > > + cd client && > > + git fetch-pack --all ../empty.git > > + ) > > +'
Re: [PATCH] fetch-pack: demonstrate --all failure when remote is empty
Kirill Smelkov writes: > ( Junio, please pick up the patch provided in the end ) > > On Tue, Jun 12, 2018 at 06:54:17PM +, Kirill Smelkov wrote: >> On Tue, Jun 12, 2018 at 05:48:49AM -0400, Jeff King wrote: >> > On Mon, Jun 11, 2018 at 09:43:02AM +, Kirill Smelkov wrote: > [...] > >> > > I'm not sure, but I would say that `fetch-pack --all` from an empty >> > > repository should not fail and should just give empty output as fetch >> > > does. >> > >> > Yeah, that seems reasonable to me. The die() that catches this dates >> > back to 2005-era, and we later taught the "fetch" porcelain to handle >> > this. I don't _think_ anybody would be upset that the plumbing learned >> > to treat this as a noop. It's probably a one-liner change in >> > fetch_pack() to return early instead of dying. I actually have a slight preference to the current "attempting to fetch from a total emptiness is so rare that it is worth grabbing attention of whoever does so" behaviour, to be honest. Oh, wait, is this specific to "fetch-pack" and the behaviour of end-user-facing "git fetch" is kept same as before? If then, I'd be somewhat sympathetic to the cause---it would be more convenient for the calling Porcelain script if this turned into a silent noop (even though it would probably make it harder to diagnose when such a Porcelain is set up incorrectly e.g. pointing at an empty repository that is not the one the Porcelain writer intended to fetch from). > However with transport.c being there too, since I'm no longer using > `fetch-pack --all`, now it is best for me to not delve into this story > and just stop with attached patch. If we do not plan to change the behaviour later ourselves, I do not think it makes sense, nor it is fair to those future developers who inherit this project, to declare that the established behaviour is wrong with an 'expect-failure' test like this, to be honest. > +test_expect_failure 'test --all wrt empty.git' ' > + git init --bare empty.git && > + ( > + cd client && > + git fetch-pack --all ../empty.git > + ) > +'
[PATCH] fetch-pack: demonstrate --all failure when remote is empty
( Junio, please pick up the patch provided in the end )
On Tue, Jun 12, 2018 at 06:54:17PM +, Kirill Smelkov wrote:
> On Tue, Jun 12, 2018 at 05:48:49AM -0400, Jeff King wrote:
> > On Mon, Jun 11, 2018 at 09:43:02AM +, Kirill Smelkov wrote:
[...]
> > > I'm not sure, but I would say that `fetch-pack --all` from an empty
> > > repository should not fail and should just give empty output as fetch
> > > does.
> >
> > Yeah, that seems reasonable to me. The die() that catches this dates
> > back to 2005-era, and we later taught the "fetch" porcelain to handle
> > this. I don't _think_ anybody would be upset that the plumbing learned
> > to treat this as a noop. It's probably a one-liner change in
> > fetch_pack() to return early instead of dying.
>
> Ok, I will try to send related testcase, and it is indeed easy to find
> - the fix itself.
I started doing it in full with the following
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1581,6 +1581,8 @@ struct ref *fetch_pack(struct fetch_pack_args *args,
if (!ref) {
packet_flush(fd[1]);
+ if (nr_sought == 0) // XXX or better args->fetch_all
+ return NULL; /* nothing to fetch */
die(_("no matching remote head"));
}
prepare_shallow_info(, shallow);
but then came to the fact that !ref fetch_pack() return is analyzed in 2
places:
- in builtin/fetch-pack.c itself:
ref = fetch_pack(, fd, conn, ref, dest, sought, nr_sought,
, pack_lockfile_ptr, protocol_v0);
...
ret = !ref;
- and in transport.c in fetch_refs_via_pack():
case protocol_v1:
case protocol_v0:
refs = fetch_pack(, data->fd, data->conn,
refs_tmp ? refs_tmp : transport->remote_refs,
dest, to_fetch, nr_heads, >shallow,
>pack_lockfile, data->version);
break;
...
if (refs == NULL)
ret = -1;
As I don't know git codebase well-enough I don't see offhand how to
distinguish empty result from a real error when something was requested
and not fetched. If it would be only builtin/fetch-pack I could start to
play ugly games with analyzing too in the calling site args.fetch_all
and nr_though and if at that level we also know we requested nothing,
don't treat !refs as an error.
However with transport.c being there too, since I'm no longer using
`fetch-pack --all`, now it is best for me to not delve into this story
and just stop with attached patch.
Thanks,
Kirill
8<
>From 76d80ffcfd4574715545c62413d64d40af063d09 Mon Sep 17 00:00:00 2001
From: Kirill Smelkov
Date: Wed, 13 Jun 2018 15:46:00 +0300
Subject: [PATCH] fetch-pack: demonstrate --all failure when remote is empty
Currently `fetch-pack --all` from an empty repository gives:
fatal: no matching remote head
However it would be logical for this fetch operation to succeed with
empty result. Add test showing the failure.
Signed-off-by: Kirill Smelkov
---
t/t5500-fetch-pack.sh | 8
1 file changed, 8 insertions(+)
diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index 82aee1c2d8..2234bad411 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -528,6 +528,14 @@ test_expect_success 'test --all with tag to non-tip' '
)
'
+test_expect_failure 'test --all wrt empty.git' '
+ git init --bare empty.git &&
+ (
+ cd client &&
+ git fetch-pack --all ../empty.git
+ )
+'
+
test_expect_success 'shallow fetch with tags does not break the repository' '
mkdir repo1 &&
(
--
2.18.0.rc1.253.gf85a566b11.dirty
