add diff to gh action size (#20889)

* Diff dev assets

* Add diff to size action

* Fix diff

* Fix diff

* Update size

* Demo

* hm

* hm

* hm

* hm

* hm

* hm

* hm

* hm

* Revert "Demo"

This reverts commit c520b6f.

Author: NullVoxPopuli

.github/workflows/size-comment.yml

@@ -89,6 +89,22 @@ jobs:
           done <<< $(cat out.txt)
           echo 'EOF' >> $GITHUB_OUTPUT
 
+      - name: "[Dev] calculate diff"
+        run: |
+          # diff exits with status 1 if there is a diff
+          diff -u main/out.txt ${{ steps.find-pr-txt.outputs.txtPath }} > dev-diff.txt || echo "Differences exist"
+          cat dev-diff.txt
+
+      - name: "[Dev] store diff in GITHUB_OUTPUT"
+        id: dev-diff
+        run: |
+          echo 'diffText<<EOF' >> $GITHUB_OUTPUT
+          while IFS= read -r line; do
+              echo "$line" >> $GITHUB_OUTPUT
+          done <<< $(cat ./dev-diff.txt)
+          echo 'EOF' >> $GITHUB_OUTPUT
+
+
 
       - name: "[Debug] collected data from artifacts"
         run: |
@@ -101,6 +117,10 @@ jobs:
           echo "PR out.txt"
           echo -e "${{ steps.dev.outputs.sizes }}"
 
+          echo "Dev diff"
+          echo -e "${{ steps.dev-diff.outputs.diffText }}"
+
+
       #########################
       # Intended Layout:
       #
@@ -117,6 +137,16 @@ jobs:
         with:
           issue: ${{ steps.find-pr-number.outputs.prNumber }}
           message: |
+            <details><summary>Development Assets</summary>
+
+            Diff
+
+            ```diff
+            ${{ steps.dev-diff.outputs.diffText }}
+            ```
+
+            Details
+
             <table><thead><tr><th></th><th>This PR</th><th>main</th></tr></thead>
             <tbody>
             <tr><td>Dev</td><td>
@@ -133,6 +163,7 @@ jobs:
 
             </td></tr>
             </tbody></table>
+            </details>