I have a project of 300+ lines, however I only want to review a part of the project. The project is hosted on GitHub.
Does that mean that I have to post the full 300+ lines and highlight that I want a specific part of the code reviewed? Or is a link to the GitHub project sufficient if I post only the amount I want to have reviewed?
Post the relevant code you want reviewed and include a link to the GitHub repository.
You may include additional code you don't want reviewed, if you think it will help reviewers (for example, it might be easier than reading two tabs in parallel). In that case, indicate clearly the parts you don't want reviewed.
See also similar discussions on this site, especially this one.
As @rolfl pointed out in a comment, this is also great reading: How to get the best value out of Code Review - Asking Questions
