diff mbox series

fetch-pack: in partial clone, pass --promisor

Message ID 20200820175116.3889786-1-jonathantanmy@google.com (mailing list archive)
State Superseded
Headers show
Series fetch-pack: in partial clone, pass --promisor | expand

Commit Message

Jonathan Tan Aug. 20, 2020, 5:51 p.m. UTC
When fetching a pack from a promisor remote, the corresponding .promisor
file needs to be created. "fetch-pack" originally did this by passing
"--promisor" to "index-pack", but in 5374a290aa ("fetch-pack: write
fetched refs to .promisor", 2019-10-16), "fetch-pack" was taught to do
this itself instead, because it needed to store ref information in the
.promisor file.

This causes a problem with superprojects when transfer.fsckobjects is
set, because in the current implementation, it is "index-pack" that
calls fsck_finish() to check the objects; before 5374a290aa,
fsck_finish() would see that .gitmodules is a promisor object and
tolerate it being missing, but after, there is no .promisor file (at the
time of the invocation of fsck_finish() by "index-pack") to tell it that
.gitmodules is a promisor object, so it returns an error.

Therefore, teach "fetch-pack" to pass "--promisor" to index pack once
again. "fetch-pack" will subsequently overwrite this file with the ref
information.

An alternative is to instead move object checking to "fetch-pack", and
let "index-pack" only index the files. However, since "index-pack" has
to inflate objects in order to index them, it seems reasonable to also
let it check the objects (which also require inflated files).

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
 fetch-pack.c             | 17 ++++++++++-------
 t/t5616-partial-clone.sh | 16 ++++++++++++++++
 2 files changed, 26 insertions(+), 7 deletions(-)

Comments

Junio C Hamano Aug. 20, 2020, 8:11 p.m. UTC | #1
Jonathan Tan <jonathantanmy@google.com> writes:

> When fetching a pack from a promisor remote, the corresponding .promisor
> file needs to be created. "fetch-pack" originally did this by passing
> "--promisor" to "index-pack", but in 5374a290aa ("fetch-pack: write
> fetched refs to .promisor", 2019-10-16), "fetch-pack" was taught to do
> this itself instead, because it needed to store ref information in the
> .promisor file.

So is this patch a fix for a regression in v2.25?

> This causes a problem ...
> ...
> An alternative is to instead move object checking to "fetch-pack", and
> let "index-pack" only index the files. However, since "index-pack" has
> to inflate objects in order to index them, it seems reasonable to also
> let it check the objects (which also require inflated files).

I can see why it might feel attractive to draw the line to divide
the labor between the two that way, but I 100% agree with your
reasoning---index-pack needs to inspect the objects in order for it
to be able to index, and in order for us to be able to trust the
resulting index, it should be validating the objects it identified
while it was indexing the pack stream.

> +
> +		if (args->from_promisor)
> +			/*
> +			 * write_promisor_file() may be called afterwards but
> +			 * we still need index-pack to know that this is a
> +			 * promisor pack. For example, if transfer.fsckobjects
> +			 * is true, index-pack needs to know that .gitmodules
> +			 * is a promisor object (so that it won't complain if
> +			 * it is missing).
> +			 */
>  			strvec_push(&cmd.args, "--promisor");
>  	}
>  	else {
> diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
> index 8827c2ed18..5a01466db4 100755
> --- a/t/t5616-partial-clone.sh
> +++ b/t/t5616-partial-clone.sh
> @@ -163,6 +163,22 @@ test_expect_success 'manual prefetch of missing objects' '
>  	test_line_count = 0 observed.oids
>  '
>  
> +test_expect_success 'partial clone with transfer.fsckobjects=1 works with submodules' '
> +	test_create_repo submodule &&
> +	test_commit -C submodule mycommit &&
> +
> +	test_create_repo src_with_sub &&
> +	test_config -C src_with_sub uploadpack.allowfilter 1 &&
> +	test_config -C src_with_sub uploadpack.allowanysha1inwant 1 &&
> +
> +	git -C src_with_sub submodule add "file://$(pwd)/submodule" mysub &&
> +	git -C src_with_sub commit -m "commit with submodule" &&
> +
> +	git -c transfer.fsckobjects=1 \
> +		clone --filter="blob:none" "file://$(pwd)/src_with_sub" dst &&
> +	test_when_finished rm -rf dst
> +'
> +
>  test_expect_success 'partial clone with transfer.fsckobjects=1 uses index-pack --fsck-objects' '
>  	git init src &&
>  	test_commit -C src x &&
Jonathan Tan Aug. 21, 2020, 9:08 p.m. UTC | #2
> Jonathan Tan <jonathantanmy@google.com> writes:
> 
> > When fetching a pack from a promisor remote, the corresponding .promisor
> > file needs to be created. "fetch-pack" originally did this by passing
> > "--promisor" to "index-pack", but in 5374a290aa ("fetch-pack: write
> > fetched refs to .promisor", 2019-10-16), "fetch-pack" was taught to do
> > this itself instead, because it needed to store ref information in the
> > .promisor file.
> 
> So is this patch a fix for a regression in v2.25?

Yes. (Just checked with "git merge-base" that 5374a290aa is in v2.25.0
but not v2.24.0.)
Junio C Hamano Aug. 21, 2020, 9:42 p.m. UTC | #3
Jonathan Tan <jonathantanmy@google.com> writes:

>> Jonathan Tan <jonathantanmy@google.com> writes:
>> 
>> > When fetching a pack from a promisor remote, the corresponding .promisor
>> > file needs to be created. "fetch-pack" originally did this by passing
>> > "--promisor" to "index-pack", but in 5374a290aa ("fetch-pack: write
>> > fetched refs to .promisor", 2019-10-16), "fetch-pack" was taught to do
>> > this itself instead, because it needed to store ref information in the
>> > .promisor file.
>> 
>> So is this patch a fix for a regression in v2.25?
>
> Yes. (Just checked with "git merge-base" that 5374a290aa is in v2.25.0
> but not v2.24.0.)

Thanks.  

I wonder how we missed the breakage back then, but better late than
never ;-)
diff mbox series

Patch

diff --git a/fetch-pack.c b/fetch-pack.c
index 7f20eca4f8..d467edc24e 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -866,13 +866,16 @@  static int get_pack(struct fetch_pack_args *args,
 			 * have this responsibility.
 			 */
 			args->check_self_contained_and_connected = 0;
-		/*
-		 * If we're obtaining the filename of a lockfile, we'll use
-		 * that filename to write a .promisor file with more
-		 * information below. If not, we need index-pack to do it for
-		 * us.
-		 */
-		if (!(do_keep && pack_lockfiles) && args->from_promisor)
+
+		if (args->from_promisor)
+			/*
+			 * write_promisor_file() may be called afterwards but
+			 * we still need index-pack to know that this is a
+			 * promisor pack. For example, if transfer.fsckobjects
+			 * is true, index-pack needs to know that .gitmodules
+			 * is a promisor object (so that it won't complain if
+			 * it is missing).
+			 */
 			strvec_push(&cmd.args, "--promisor");
 	}
 	else {
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 8827c2ed18..5a01466db4 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -163,6 +163,22 @@  test_expect_success 'manual prefetch of missing objects' '
 	test_line_count = 0 observed.oids
 '
 
+test_expect_success 'partial clone with transfer.fsckobjects=1 works with submodules' '
+	test_create_repo submodule &&
+	test_commit -C submodule mycommit &&
+
+	test_create_repo src_with_sub &&
+	test_config -C src_with_sub uploadpack.allowfilter 1 &&
+	test_config -C src_with_sub uploadpack.allowanysha1inwant 1 &&
+
+	git -C src_with_sub submodule add "file://$(pwd)/submodule" mysub &&
+	git -C src_with_sub commit -m "commit with submodule" &&
+
+	git -c transfer.fsckobjects=1 \
+		clone --filter="blob:none" "file://$(pwd)/src_with_sub" dst &&
+	test_when_finished rm -rf dst
+'
+
 test_expect_success 'partial clone with transfer.fsckobjects=1 uses index-pack --fsck-objects' '
 	git init src &&
 	test_commit -C src x &&