CI: Push wasm commit on changes only

When rerunning the deploy wasm CI, previously successful jobs may fail
due to a reproducible error:
nothing to commit, working tree clean
Error: Process completed with exit code 1.

This occurs because the successful deployment has already committed the
changes. To prevent this, the workflow should check whether there are
any staged changes before attempting to commit. If there’s nothing to
commit, skip the push step. Otherwise, proceed with committing and
pushing the new changes.

Author: ChinYikMing

.github/workflows/deploy-wasm.yml

@@ -92,18 +92,22 @@ jobs:
             mv /tmp/rv32emu-system-demo/rv32emu.wasm ./system
             mv /tmp/rv32emu-system-demo/rv32emu.worker.js ./system
       - name: Commit files
+        id: commit
         if: ${{ steps.changed-files.outputs.any_modified == 'true' ||
             github.event_name == 'workflow_dispatch' ||
             (github.event_name == 'repository_dispatch' && github.event.action == 'deploy_system_wasm') }}
         run: |
             git config --local user.email "github-actions[bot]@users.noreply.github.com"
             git config --local user.name "github-actions[bot]"
             git add system/
-            git commit -m "Add changes to system emulation"
+            if git diff --cached --quiet; then
+              echo "committed=false" >> $GITHUB_OUTPUT
+            else
+              git commit -m "Add changes to system emulation"
+              echo "committed=true" >> $GITHUB_OUTPUT
+            fi
       - name: Push changes
-        if: ${{ steps.changed-files.outputs.any_modified == 'true' ||
-            github.event_name == 'workflow_dispatch' ||
-            (github.event_name == 'repository_dispatch' && github.event.action == 'deploy_system_wasm') }}
+        if: steps.commit.outputs.committed == 'true'
         uses: ad-m/github-push-action@master
         with:
           repository: sysprog21/rv32emu-demo
@@ -184,18 +188,22 @@ jobs:
             mv /tmp/rv32emu-demo/rv32emu.wasm .
             mv /tmp/rv32emu-demo/rv32emu.worker.js .
       - name: Commit files
+        id: commit
         if: ${{ steps.changed-files.outputs.any_modified == 'true' ||
             github.event_name == 'workflow_dispatch' ||
             (github.event_name == 'repository_dispatch' && github.event.action == 'deploy_user_wasm') }}
         run: |
             git config --local user.email "github-actions[bot]@users.noreply.github.com"
             git config --local user.name "github-actions[bot]"
             git add --all
-            git commit -m "Add changes to user emulation"
+            if git diff --cached --quiet; then
+              echo "committed=false" >> $GITHUB_OUTPUT
+            else
+              git commit -m "Add changes to user emulation"
+              echo "committed=true" >> $GITHUB_OUTPUT
+            fi
       - name: Push changes
-        if: ${{ steps.changed-files.outputs.any_modified == 'true' ||
-            github.event_name == 'workflow_dispatch' ||
-            (github.event_name == 'repository_dispatch' && github.event.action == 'deploy_user_wasm') }}
+        if: steps.commit.outputs.committed == 'true'
         uses: ad-m/github-push-action@master
         with:
           repository: sysprog21/rv32emu-demo