BUG: Fixer high GitHub API usage

[azeemshaikh38]

#1566 increases the cost/complexity of the GraphQL queries. The query cost goes up ~20x due to that PR. We should fix this before the next release. 2-part solution here:

1. Decrease the number of associatedPullRequests to 1, since for every commit we are only interested in a single PR (the one used to submit the commit). Doing this brings back the cost to original, so ~20x savings.
2. Add some tests to verify the cost of our GraphQL queries. Any future issues can be caught using these tests.

I would say, we block the next release on this issue since IMO it's important to fix this.

[laurentsimon]

Can you explain how you compute the cost of a request? Is this something the API returns?
I don't follow why setting associatedPullRequests to 1 helps: I was under the impression that each commit to main has a single associated pull request anyway. I tried

{
  repository(owner: "ossf", name: "scorecard") {
    defaultBranchRef {
      target {
        ... on Commit {
          history(first: 10) {
            nodes {
              associatedPullRequests(first: 30) {
               
                  mergeCommit {
                    oid
                

and it seems to return a single PR for each commit. I've not looked at the code we use in scorecard though, but I think it's similar.

[azeemshaikh38]

Can you explain how you compute the cost of a request? Is this something the API returns?

Yes, you can add the RateLimit object to the graphQL query to get the cost of the query - https://docs.github.com/en/graphql/reference/objects#ratelimit

I don't follow why setting associatedPullRequests to 1 helps: I was under the impression that each commit to main has a single associated pull request anyway.

That is correct. But if you say first: 1 vs. first: 30 (for associatedPR), the cost of the query that you get is different. I presume GitHub makes an approximate charge based on the complexity of the query, so a query for more items is more expensive even if it ends up returning lesser number of items.