Upload lychee results to GH artifacts for excessively long reports

.github/workflows/build-pr-preview.yml

@@ -320,8 +320,40 @@ jobs:
         run: |
           sed -i '1s/^/## Broken Link Checker\n/' ./lychee/out.md
 
-      - name: Comment on PR about a failed link check
+      # Get length of lychee output
+      - name: lychee output size check
+        id: char-count
+        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
         if: steps.lychee.outputs.exit_code != 0
+        with:
+          script: |
+            const size = require('fs').readFileSync('./lychee/out.md').length;
+            console.log(`${size} characters`);
+            core.setOutput('size', size);
+
+      # If the char count of the lychee report is too long, it's going to break
+      # the sticky-pull-request-comment action because of a body size limitation
+      # on the GitHub PR comment API. So, instead, upload the full report to GH
+      # artifacts and just link to that instead
+      - name: Upload lychee report to GitHub artifacts
+        id: upload-artifact
+        if: steps.lychee.outputs.exit_code != 0 && fromJson(steps.char-count.outputs.size) >= fromJson(vars.BROKEN_LINK_REPORT_CHAR_MAX)
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # 4.6.2
+        with:
+          path: ./lychee/out.md
+          name: Link Checker Report
+
+      - name: Comment on PR with link to full link checker report
+        if: steps.lychee.outputs.exit_code != 0 && fromJson(steps.char-count.outputs.size) >= fromJson(vars.BROKEN_LINK_REPORT_CHAR_MAX)
+        uses: marocchino/sticky-pull-request-comment@52423e01640425a022ef5fd42c6fb5f633a02728 # v2.9.1
+        with:
+          header: Link Checker Report
+          message: |
+            ## Broken Link Checker
+            Report exceeds max length of ${{vars.BROKEN_LINK_REPORT_CHAR_MAX}} characters, so it cannot be displayed in GitHub comments. [Download full report.](${{steps.upload-artifact.outputs.artifact-url}})
+
+      - name: Comment on PR with link checker report
+        if: steps.lychee.outputs.exit_code != 0 && fromJson(steps.char-count.outputs.size) < fromJson(vars.BROKEN_LINK_REPORT_CHAR_MAX)
         uses: marocchino/sticky-pull-request-comment@52423e01640425a022ef5fd42c6fb5f633a02728 # v2.9.1
         with:
           header: Link Checker Report