threads / bug / 59947

Bug report: AM 3-way patching fails with partial cloning

Subject: Bug report: AM 3-way patching fails with partial cloning

## tl;dr

2 messages between Jul 3, 2023 and Jul 4, 2023.

replies: 1people: 2as markdown or json

Marius Schiffer· Jul 3, 2023, 16:46 UTC · lore

When applying patches with git am on a repository cloned with filter=blob:none, the patching sometimes fails when it can't find the required SHA1 information. Applying the same thing on a normal clone works. I'm not sure yet what exactly i s missing that is not fetched, but I guess git should be able to fetch the missing blobs. I would also be very happy to hear workarounds, as I really love git partial cloning.

Using git v2.41.0.

To reproduce:

1. Download this patch: 
https://raw.githubusercontent.com/projectceladon/vendor-intel-utils/master/bsp_diff/common/kernel/linux-intel-lts2021/0007-9p-freezing-aborts-when-use-wait_event_killable.patch

2. Clone this repository: git clone --filter=blob:none 
https://github.com/projectceladon/linux-intel-lts2021

3. Apply the patch: git am -3 
../0007-9p-freezing-aborts-when-use-wait_event_killable.patch

-- Marius

Junio C Hamano· Jul 4, 2023, 22:02 UTC · re: Marius Schiffer · lore

Re: Bug report: AM 3-way patching fails with partial cloning

Marius Schiffer <marius@mschiffer.de> writes:

> When applying patches with git am on a repository cloned with
> filter=blob:none, the patching sometimes fails when it can't find the
> required SHA1 information.
> Applying the same thing on a normal clone works.

This is very much expected, especially if your patches are not generated with --full-index option, because partial clones cannot on-demand request objects without knowing their full object names to the promissor remote. I do not offhand know if "am -3" codepath, if the full object name is available, is arranged to trigger lazy fetching of the objects, but nobody sane are sending patches with the --full-index option to begin with, so that is academic, I would say.