ci: when looking for successful workflow jobs, use a smart order

There might be runs for the very same commit, those should be looked at
first. Then there might be runs that have not yet finished; Let's first
look at the finished ones.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

.github/workflows/build.yaml

@@ -95,12 +95,33 @@ jobs:
               per_page: 500,
               workflow_id,
             });
-            for (const run of runs.workflow_runs) {
+            // first look at commit-same runs, then at finished ones, then at in-progress ones
+            const rank = (a) => (a.status === 'in_progress' ? 0 : (head_sha === a.head_sha ? 2 : 1))
+            const demoteInProgressToEnd = (a, b) => (rank(b) - rank(a))
+            for (const run of runs.workflow_runs.sort(demoteInProgressToEnd)) {
               let reason
               if (head_sha === run.head_sha) reason = 'the same commit'
               else if (tree_id === run.head_commit?.tree_id) reason = 'a tree-same commit'
               else continue
 
+              if (run.status === 'in_progress') {
+                // poll until the run is done
+                const pollIntervalInSeconds = 30
+                let seconds = 0
+                for (;;) {
+                  console.log(`Found existing, in-progress run at ${run.html_url}; Waiting for it to finish (waited ${seconds} seconds so far)...`)
+                  await new Promise((resolve) => { setTimeout(resolve, pollIntervalInSeconds * 1000) })
+                  seconds += pollIntervalInSeconds
+
+                  const { data: polledRun } = await github.rest.actions.getWorkflowRun({
+                    owner: context.repo.owner,
+                    repo: context.repo.repo,
+                    run_id: run.id
+                  })
+                  if (polledRun.status !== 'in_progress') break
+                }
+              }
+
               const { data: jobs } = await github.rest.actions.listJobsForWorkflowRun({
                 owner: context.repo.owner,
                 repo: context.repo.repo,