Error `merge_base': object not found - no match for id

[radek-polcode]

We've encountered an error when using code for github actions integration:

/opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/pronto-0.11.0/lib/pronto/git/repository.rb:87:in `merge_base': object not found - no match for id (646d05a0a847592a34024edb97fcfbd4902368d3) (Rugged::OdbError)
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/pronto-0.11.0/lib/pronto/git/repository.rb:87:in `merge_base'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/pronto-0.11.0/lib/pronto/git/repository.rb:17:in `diff'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/pronto-0.11.0/lib/pronto.rb:64:in `run'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/pronto-0.11.0/lib/pronto/cli.rb:66:in `block in run'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/pronto-0.11.0/lib/pronto/cli.rb:64:in `chdir'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/pronto-0.11.0/lib/pronto/cli.rb:64:in `run'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/thor-1.1.0/lib/thor/command.rb:27:in `run'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/thor-1.1.0/lib/thor/invocation.rb:127:in `invoke_command'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/thor-1.1.0/lib/thor.rb:392:in `dispatch'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/thor-1.1.0/lib/thor/base.rb:485:in `start'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/lib/ruby/gems/2.6.0/gems/pronto-0.11.0/bin/pronto:6:in `<top (required)>'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/bin/pronto:23:in `load'
	from /opt/hostedtoolcache/Ruby/2.6.5/x64/bin/pronto:23:in `<main>'

The solution was to remove --depth=10 from git fetch --no-tags --prune --depth=10 origin +refs/heads/*:refs/remotes/origin/*. I'm leaving it here, may be useful for someone, but maybe there is something better we can do to get rid of this error?

[PikachuEXE]

I am not git expert
Just providing some doc about depth here:

• https://git-scm.com/docs/git-fetch#Documentation/git-fetch.txt---depthltdepthgt
• https://git-scm.com/docs/git-clone#Documentation/git-clone.txt---depthltdepthgt (pointed by description in git fetch)

[Skipants]

Ran into and fixed this, myself. Albeit the fix was removing depth which isn't ideal.

I believe this happens because Rugged, the dependency pronto uses, can't crawl your git history to get your merge base between your branch and the compared branch (I'm assuming main/master). This happens if your supplied --depth is less than the merge base commit.

I don't know if there's a good way around it. If you're using depth because of a large git repo, you can consider setting a high depth or a long --shallow-since= date that you think you'll never hit with your development branches. Maybe there's something smart you can try with --deepen= but I haven't used that flag myself.

[rangerscience]

We just ran into this, and I'm playing around with something like:

jobs:
  pronto:
    steps:
      - name: Checkout code
        uses: actions/checkout@v2
      - run: |
          git fetch --no-tags --prune --depth=1 origin +refs/heads/*:refs/remotes/origin/*
          git fetch --no-tags --prune --shallow-since="$(git show -s --format=%ci  origin/master)" origin +refs/heads/*:refs/remotes/origin/*

That's probably not correct yet tho.

[sramsden]

I had a similar problem but it was because the initial checkout defaults to --depth=1 as documented by https://github.com/actions/checkout#usage fetch-depth param.
If my feature branch only had one commit then fine, but normally they don't before PR created so I set ..

    steps:
      - name: Checkout code
        uses: actions/checkout@v2
        with:
          fetch-depth: 100

.. where 100 is arbitrary but hopefully big enough to cover all commits on the feature branch since it was forked from master.

[KieranP]

After years of it working fine, I've suddenly started seeing the same error when running on CircleCI ("object not found - cannot read header for (7c12bff1f6ffc4e442e24949edcf31cdbe438fb0)"), but unlike suggestions above, CircleCI doesn;t use a shallow clone. When I SSH onto the CI box and run git fetch --unshallow I see --unshallow on a complete repository does not make sense. So in theory, pronto/rugged should have access to all the information it needs. When SSHd into the box, the git repo is usable (can pull/fetch without issues). Any suggestions for other things I could try?

[quarkgluant]

Like @KieranP after years of it working fine on CircleCi, I've seeing this error
/home/circleci/repo/vendor/bundle/ruby/3.3.0/gems/pronto-0.11.2/lib/pronto/git/patches.rb:11:in 'each_patch': object not found - cannot read header for (d7655e8ce194095299e5d85b4650d2a66f004b26) (Rugged::OdbError) and have tried what I have read here, without success.
Via SSH I've tried

repo = Rugged::Repository.new('path/to/my/repository')
repo.exists?("d7655e8ce194095299e5d85b4650d2a66f004b26")
# => false

The same CircleCI configuration on another rails app, same version of Ruby and of Rails, does not produce this issue 🤔

[quarkgluant]

I think I have a clue, comparing the CI on this 2 similar app (same versions of Ruby/Rails/Pronto/Pronto-Rubocop and same config.yml for the configuration of the CircleCI). As you can see on the capture, selected in blue, on the failing CI there is this Creating a blobless clone for better performance which does not come from the .circleci/config.yml

[KieranP]

@quarkgluant Hmm, so CircleCI may have changed how their 'checkout' helper step operates.

As a workaround, I added this to my config, which seems to fix it:

      # Workaround for "object not found - cannot read header"
      # Refetch and reset to commit SHA
      - run: git checkout master
      - run: git fetch
      - run: git reset --hard $CIRCLE_SHA1
      - run: bundle exec pronto run -c origin/master --exit-code

[pbourdet]

Got a similar error :

/home/runner/work/project/project/vendor/bundle/ruby/3.1.0/gems/pronto-0.11.2/lib/pronto/git/repository.rb:99:in `merge_base': revspec 'origin/master' not found (Rugged::ReferenceError)
	from /home/runner/work/project/project/vendor/bundle/ruby/3.1.0/gems/pronto-0.11.2/lib/pronto/git/repository.rb:99:in `merge_base'
	from /home/runner/work/project/project/vendor/bundle/ruby/3.1.0/gems/pronto-0.11.2/lib/pronto/git/repository.rb:29:in `diff'
	from /home/runner/work/project/project/vendor/bundle/ruby/3.1.0/gems/pronto-0.11.2/lib/pronto.rb:64:in `run'

My fix was adding fetch_depth: 0 in the checkout action. Not sure if this is the best solution but it works 🤷

      - name: Checkout code
        uses: actions/checkout@v4
        with:
          fetch-depth: 0