Error opening a present `build.gradle` file

[alexander-yevsyukov]

When building spine.io by GitHub Actions I repeatedly get the following error:

Run ./_script/check-samples
Configuration file: /home/runner/work/SpineEventEngine.github.io/SpineEventEngine.github.io/_config.yml
/opt/hostedtoolcache/Ruby/2.7.1/x64/lib/ruby/gems/2.7.0/bundler/gems/embed-code-00d9e3083ff8/lib/commands/fragmentation.rb:342:in `content': Fragment file `/home/runner/work/SpineEventEngine.github.io/SpineEventEngine.github.io/.fragments/examples/hello/build.gradle` not found. This may indicate that the file is not includedin `code_includes` or is not readable. (RuntimeError)
jekyll 3.8.7 | Error:  Fragment file `/home/runner/work/SpineEventEngine.github.io/SpineEventEngine.github.io/.fragments/examples/hello/build.gradle` not found. This may indicate that the file is not includedin `code_includes` or is not readable.
	from /opt/hostedtoolcache/Ruby/2.7.1/x64/lib/ruby/gems/2.7.0/bundler/gems/embed-code-00d9e3083ff8/lib/commands/embedding_instruction.rb:80:in `content'
	from /opt/hostedtoolcache/Ruby/2.7.1/x64/lib/ruby/gems/2.7.0/bundler/gems/embed-code-00d9e3083ff8/lib/commands/embedding.rb:254:in `render_sample'
	from /opt/hostedtoolcache/Ruby/2.7.1/x64/lib/ruby/gems/2.7.0/bundler/gems/embed-code-00d9e3083ff8/lib/commands/embedding.rb:243:in `accept'
...

The check-samples script executed by GitHub does this:

source ~/.bash_profile
bundle exec jekyll checkCodeSamples

The error does not happen when running the check-samples script locally. And the .fragments directory on my machine does have the examples/hello/build.gradle file.

I suspect that the reason for the error could be concurrent file access with Gradle, which may lock the build.gradle file at some stage.