check for artifact presence

.github/workflows/make_card_db_pr.yml

@@ -14,27 +14,38 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: actions/github-script@v3.1.0
+        id: get-metadata
         with:
+          result-encoding: string
           script: |
             var artifacts = await github.actions.listWorkflowRunArtifacts({
                owner: context.repo.owner,
                repo: context.repo.repo,
                run_id: ${{github.event.workflow_run.id }},
             });
-            var matchArtifact = artifacts.data.artifacts.filter((artifact) => {
+            var matchArtifacts = artifacts.data.artifacts.filter((artifact) => {
               return artifact.name == "card_db"
-            })[0];
-            var download = await github.actions.downloadArtifact({
-               owner: context.repo.owner,
-               repo: context.repo.repo,
-               artifact_id: matchArtifact.id,
-               archive_format: 'zip',
             });
-            var fs = require('fs');
+            if (matchArtifacts.length > 0) {
-            fs.writeFileSync('${{github.workspace}}/card_db.zip', Buffer.from(download.data));
+              var matchArtifact = matchArtifacts[0];
+              var download = await github.actions.downloadArtifact({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                artifact_id: matchArtifact.id,
+                archive_format: 'zip',
+              });
+              var fs = require('fs');
+              fs.writeFileSync('${{github.workspace}}/card_db.zip', Buffer.from(download.data));
+              return 'found_artifact';
+            } else {
+              return 'no_artifact'
+            }
       - run: unzip -d src/domdiv/card_db card_db.zip
+        if: steps.get-metadata.output.result == 'found_artifact'
       - run: rm -f card_db.zip
+        if: steps.get-metadata.output.result == 'found_artifact'
       - name: Make PR
+        if: steps.get-metadata.output.result == 'found_artifact'
         uses: peter-evans/create-pull-request@v3
         with:
           body: |