ci/get-merge-commit.sh

   1 #!/usr/bin/env bash
   2 # See ./README.md for docs
   3
   4 set -euo pipefail
   5
   6 log() {
   7     echo "$@" >&2
   8 }
   9
  10 if (( $# < 2 )); then
  11     log "Usage: $0 GITHUB_REPO PR_NUMBER"
  12     exit 99
  13 fi
  14 repo=$1
  15 prNumber=$2
  16
  17 # Retry the API query this many times
  18 retryCount=5
  19 # Start with 5 seconds, but double every retry
  20 retryInterval=5
  21
  22 while true; do
  23     log "Checking whether the pull request can be merged"
  24     prInfo=$(gh api \
  25         -H "Accept: application/vnd.github+json" \
  26         -H "X-GitHub-Api-Version: 2022-11-28" \
  27         "/repos/$repo/pulls/$prNumber")
  28
  29     # Non-open PRs won't have their mergeability computed no matter what
  30     state=$(jq -r .state <<< "$prInfo")
  31     if [[ "$state" != open ]]; then
  32         log "PR is not open anymore"
  33         exit 1
  34     fi
  35
  36     mergeable=$(jq -r .mergeable <<< "$prInfo")
  37     if [[ "$mergeable" == "null" ]]; then
  38         if (( retryCount == 0 )); then
  39             log "Not retrying anymore. It's likely that GitHub is having internal issues: check https://www.githubstatus.com/"
  40             exit 3
  41         else
  42             (( retryCount -= 1 )) || true
  43
  44             # null indicates that GitHub is still computing whether it's mergeable
  45             # Wait a couple seconds before trying again
  46             log "GitHub is still computing whether this PR can be merged, waiting $retryInterval seconds before trying again ($retryCount retries left)"
  47             sleep "$retryInterval"
  48
  49             (( retryInterval *= 2 )) || true
  50         fi
  51     else
  52         break
  53     fi
  54 done
  55
  56 if [[ "$mergeable" == "true" ]]; then
  57     log "The PR can be merged"
  58     jq -r .merge_commit_sha <<< "$prInfo"
  59 else
  60     log "The PR has a merge conflict"
  61     exit 2
  62 fi