Re: [PATCH v2 8/8] check-whitespace: detect if no base_commit is provided

> The 'check-whitespace' CI script exits gracefully if no base commit is
> provided or if an invalid revision is provided. This is not good because
> if a particular CI provides an incorrect base_commit, it would fail
> successfully.
> 
> This is exactly the case with the GitLab CI. The CI is using the
> "$CI_MERGE_REQUEST_TARGET_BRANCH_SHA" variable to get the base commit
> SHA, but variable is only defined for _merged_ pipelines. So it is empty
> for regular pipelines [1]. This should've failed the check-whitespace
> job.
> 
> Let's fallback to 'CI_MERGE_REQUEST_DIFF_BASE_SHA' if
> "CI_MERGE_REQUEST_TARGET_BRANCH_SHA" isn't available in GitLab CI,
> similar to the previous commit. Let's also add a check for incorrect
> base_commit in the 'check-whitespace.sh' script. While here, fix a small
> typo too.
> 
> [1]: https://docs.gitlab.com/ee/ci/variables/predefined_variables.html#predefined-variables-for-merge-request-pipelines
> 
> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
> ---
>  .gitlab-ci.yml         |  7 ++++++-
>  ci/check-whitespace.sh | 10 ++++++++--
>  2 files changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
> index dc43fc8ba8..c5a18f655a 100644
> --- a/.gitlab-ci.yml
> +++ b/.gitlab-ci.yml
> @@ -119,7 +119,12 @@ check-whitespace:
>    before_script:
>      - ./ci/install-dependencies.sh
>    script:
> -    - ./ci/check-whitespace.sh "$CI_MERGE_REQUEST_TARGET_BRANCH_SHA"
> +    - |
> +      if [ -z ${CI_MERGE_REQUEST_TARGET_BRANCH_SHA} ]; then
> +        ./ci/check-whitespace.sh "$CI_MERGE_REQUEST_DIFF_BASE_SHA"
> +      else
> +        ./ci/check-whitespace.sh "$CI_MERGE_REQUEST_TARGET_BRANCH_SHA"
> +      fi