cherry-pick shows confusing message

[smoser]

I was looking at the build log of a wolfi-dev/os#27452 here

It ends like:

2024/09/03 14:50:50 INFO built image layer tarball as /temp/apko-temp-1821752880/apko-aarch64.tar.gz
2024/09/03 14:50:50 INFO using /temp/apko-temp-1821752880/apko-aarch64.tar.gz for image layer
2024/09/03 14:50:55 INFO ImgRef = /temp/melange-guest-3599558897
2024/09/03 14:50:55 INFO running step "Check out sources from git"
2024/09/03 14:50:55 INFO [git checkout] repo='https://github.com/openssl/openssl.git' dest='.' depth='1'\
     branch='' tag='openssl-3.3.2' expcommit='fb7fab9fa6f4869eaa8fbb97e0d593159f03ffe4' recurse='false'
2024/09/03 14:50:55 INFO [git checkout] execute: git config --global --add safe.directory /tmp/tmp.vpbbqP
2024/09/03 14:50:55 INFO [git checkout] execute: git config --global --add safe.directory /home/build
2024/09/03 14:50:55 INFO [git checkout] execute: git clone --quiet --origin=origin --config=user.name=Melange Build \
    [email protected] --config=advice.detachedHead=false \
    --branch=openssl-3.3.2 --depth=1 https://github.com/openssl/openssl.git /tmp/tmp.vpbbqP
2024/09/03 14:50:58 INFO [git checkout] execute: cd /tmp/tmp.vpbbqP
2024/09/03 14:50:58 INFO [git checkout] tar -c . | tar -C "/home/build" -x
2024/09/03 14:50:59 INFO [git checkout] execute: cd /home/build
2024/09/03 14:50:59 INFO [git checkout] execute: git config --global --add safe.directory /home/build
2024/09/03 14:50:59 INFO [git checkout] execute: git fetch --quiet origin --depth=1 --no-tags +refs/tags/openssl-3.3.2:refs/origin/tags/openssl-3.3.2
2024/09/03 14:50:59 INFO [git checkout] execute: git checkout --quiet origin/tags/openssl-3.3.2
2024/09/03 14:50:59 INFO [git checkout] tag openssl-3.3.2 is fb7fab9fa6f4869eaa8fbb97e0d593159f03ffe4
2024/09/03 14:50:59 INFO [git checkout] Setting commit date to Jan 1, 1980 (SOURCE_DATE_EPOCH found 0)
2024/09/03 14:50:59 INFO [git checkout] execute: git fetch origin openssl-3.3:openssl-3.3
2024/09/03 14:50:59 WARN From https://github.com/openssl/openssl
2024/09/03 14:50:59 WARN  * [new branch]      openssl-3.3 -> openssl-3.3
2024/09/03 14:50:59 INFO [git checkout] execute: env GIT_COMMITTER_DATE=@315532800 git cherry-pick -x e86ac436f0bd54d4517745483e2315650fae7b2c
2024/09/03 14:50:59 WARN fatal: bad object e86ac436f0bd54d4517745483e2315650fae7b2c
2024/09/03 14:50:59 INFO [git checkout] failed to cherry-pick e86ac436f0bd54d4517745483e2315650fae7b2c from branch openssl-3.3
2024/09/03 14:50:59 INFO [git checkout] FAIL failed to apply cherry-pick
2024/09/03 14:50:59 ERRO ERROR: failed to build package. the build environment has been preserved:
2024/09/03 14:50:59 INFO   workspace dir: /temp/melange-workspace-391569645
2024/09/03 14:50:59 INFO   guest dir: /temp/melange-guest-2797409342
2024/09/03 14:50:59 ERRO failed to build package: unable to run package openssl pipeline: unable to run pipeline: unable to run pipeline: exit status 1
make[1]: *** [Makefile:111: packages/aarch64/openssl-3.3.2-r0.apk] Error 1

The message bad object e86ac... did not make sense to me. We explicitly did git fetch origin openssl-3.3:openssl-3.3. It should have fetched that commit id I wondered if maybe openssl mucked with their git history, as that commit was on the openssl-3.3 branch.

Further investigation shows that the 'fetch origin openssl-3.3:openssl-3.3' does not cross the .git/shallow boundary. that was established when we git cloned and pulled the openssl-3.3.2 tag. The subsequent fetch of the openssl-3.3 branch then doesn't actually do anything because it now points to the same commit (or maybe a couple ahead) of the 3.3.2 tag.

So,

1. The fetch works when the branch mentioned is newer than the tag pulled.
2. It errors with 'bad object' message if the branch pulled is the same as the tag we cloned with (or newer) because the fetch will stop at the tag.
3. to ensure that we get all the commits on a branch, we need to use --unshallow on the fetch. This will actually pull a lot more commits in almost all cases.