I found the gitlab blog post from 2017: https://about.gitlab.com/blog/2017/09/05/how-to-automatically-create-a-new-mr-on-gitlab-with-gitlab-ci/

It seems outdated(?) but I was able to use POSTMAN to carve down a working model (using token as a parameter instead of a header, etc.)

I cannot get the Merge Request to trigger and I believe it's due to --data (-d) not interpolating the variables.

I've hardcoded the payload with the values exactly, and pushed to my branch and it generated the MR just fine.

Any method I use to try and incorporate variables will result in the cURL going through, but no MR being generated.

The GL Runner does not output the response - so it's difficult to debug.

I've tried escaping with back slashes, I've tried single quote setups with escaping the single quotes and doing inner double quotes with the ${} variables, but nothing.

I've validated that the variables being sent in from the yml exists (echoing them out before the curl call and the body setup).

I've still yet to try JQ, but I'm not sure if the runner has it installed, but I'll find out.

General format of the scripts code:

#!/usr/bin/env bash
TARGET_BRANCH="test"

echo "Host: ${HOST}"
echo "Project  Id: ${CI_PROJECT_ID}
echo "SOURCE BRANCH: ${CI_COMMIT_REF_NAME}
echo "Target Branch: ${TARGET_BRANCH}

BODY="{
    \"id\": ${CI_PROJECT_ID},
    \"source_branch\": \"${CI_COMMIT_REF_NAME}\",
    \"target_branch\": \"${TARGET_BRANCH}\",
    \"remove_source_branch\": false,
    \"title\": \"WIP: ${CI_COMMIT_REF_NAME}\",
}";

echo "Body: ${BODY}"

# Create MR
curl -X POST https://${HOST}/api/v4/projects/${CI_PROJECT_ID}/merge_requests?private_token${PRIVATE_TOKEN}"\
--header "PRIVATE_TOKEN: ${PRIVATE_TOKEN}"\
--header "Content-Type: application/json"\
--data "${BODY}"

After testing this and seeing the curl go through, but no MR generated, I modified the --data value to go from ${BODY} to: (assume to be valid value, just obscured)

--data '{
  "id": ,
  "source_branch": "dev",
  "target_branch": "test",
  "remove_source_branch": false,
  "title":"WIP: dev"
}'

And this worked! I the MR generated just fine.

So I then tested by replacing the single quote with double quotes, and escaping the inner double quotes but still keeping the hardcoded values. Back to no MR being generated.

I even went back to the BODY=... block, and tried to reformat that.

Then I went to the outer single, inner double, escaping

'{
  "id": '"${CI_PROJECT_ID}"',
  ...
'}

and still nothing.