danger: Danger fails with "Cannot find a merge base between danger_base and danger_head"

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What did you do?

I’m running danger on Travis CI from a pull request.

What did you expect to happen?

Danger shouldn’t crash.

What happened instead?

There is no comment on a PR and in the travis log I see the following error:

remote: Counting objects: 5, done.
remote: Compressing objects: 100% (5/5), done.
remote: Total 5 (delta 0), reused 5 (delta 0), pack-reused 0
Unpacking objects: 100% (5/5), done.
From https://github.com/php-coder/mystamps
 * [new tag]         0.1        -> 0.1
 * [new tag]         0.1.1      -> 0.1.1
 * [new tag]         0.1.2      -> 0.1.2
 * [new tag]         0.1.3      -> 0.1.3
 * [new tag]         0.2        -> 0.2
 * [new tag]         0.3        -> 0.3
/home/travis/.rvm/gems/ruby-2.2.5/gems/danger-4.3.2/lib/danger/scm_source/git_repo.rb:77:in `find_merge_base': Cannot find a merge base between danger_base and danger_head. (RuntimeError)
	from /home/travis/.rvm/gems/ruby-2.2.5/gems/danger-4.3.2/lib/danger/scm_source/git_repo.rb:16:in `diff_for_folder'
	from /home/travis/.rvm/gems/ruby-2.2.5/gems/danger-4.3.2/lib/danger/danger_core/dangerfile.rb:259:in `setup_for_running'
	from /home/travis/.rvm/gems/ruby-2.2.5/gems/danger-4.3.2/lib/danger/danger_core/dangerfile.rb:269:in `run'
	from /home/travis/.rvm/gems/ruby-2.2.5/gems/danger-4.3.2/lib/danger/danger_core/executor.rb:27:in `run'
	from /home/travis/.rvm/gems/ruby-2.2.5/gems/danger-4.3.2/lib/danger/commands/runner.rb:66:in `run'
	from /home/travis/.rvm/gems/ruby-2.2.5/gems/claide-1.0.1/lib/claide/command.rb:334:in `run'
	from /home/travis/.rvm/gems/ruby-2.2.5/gems/danger-4.3.2/bin/danger:5:in `<top (required)>'
	from /home/travis/.rvm/gems/ruby-2.2.5/bin/danger:22:in `load'
	from /home/travis/.rvm/gems/ruby-2.2.5/bin/danger:22:in `<main>'
	from /home/travis/.rvm/gems/ruby-2.2.5/bin/ruby_executable_hooks:15:in `eval'
	from /home/travis/.rvm/gems/ruby-2.2.5/bin/ruby_executable_hooks:15:in `<main>'

Your Environment

Which CI are you running on? Travis CI
Are you running the latest version of Danger? yes
What is your Dangerfile? It’s here but error doesn’t relate to my configuration

About this issue

Original URL
State: open
Created 7 years ago
Comments: 22 (8 by maintainers)

Commits related to this issue

.travis.yml: use danger 4.3.1 to fix "Cannot find a merge base between danger_base and danger_head" error. Details: https://github.com/danger/danger/issues/768 — committed to php-coder/mystamps by php-coder 7 years ago
.travis.yml: use danger 4.3.1 to fix "Cannot find a merge base between danger_base and danger_head" error. Details: https://github.com/danger/danger/issues/768 — committed to bodom91/mystamps by php-coder 7 years ago

Most upvoted comments

Just dropping a breadcrumb: we were doing shallow clones on CI for PR builds and once the # of commits on that PR surpassed that depth, it started failing with this error

+16

iwasrobbed-ks on Jun 20, 2018

I think I forgot to comment on an update.

I’m pretty sure that what @rob-keepsafe said worked. We had shallow clone of depth 1, and once it was changed to shallow clone of depth 100 it has worked since. The 100 is just a random number to maximize the chance of this issue not happening.

kgaidis on Jan 10, 2019