Fix commit hash in benchmark pr

Author: lorenzovarese

.github/workflows/benchmark_pr.yml

@@ -64,44 +64,52 @@ jobs:
 
       - name: Run Benchmarks
         run: |
-          echo $PATH
+          echo "Current PATH: $PATH"
           mkdir results
-          benchpkg --rev="${{ github.sha }},$(git rev-parse HEAD^1)" --bench-on="${{ github.sha }}" --output-dir=results/ --tune
-
-          - name: Generate and Upload Benchmark Plots
-          run: |
-            mkdir -p plots
-            git fetch origin main:refs/remotes/origin/main
-            LAST_MAIN_COMMIT=$(git rev-parse origin/main)
-            CURRENT_COMMIT=$(git rev-parse HEAD)
-            echo "Comparing CURRENT_COMMIT ($CURRENT_COMMIT) with LAST_MAIN_COMMIT ($LAST_MAIN_COMMIT)"
-            benchpkgplot --rev="$LAST_MAIN_COMMIT,$CURRENT_COMMIT" --npart=10 --format=png --input-dir=results/ --output-dir=plots/
-          if: always()
-
+          git fetch origin main:refs/remotes/origin/main
+          if [ $(git rev-list --count HEAD) -gt 1 ]; then
+            PREV_COMMIT=$(git rev-parse HEAD^1)
+          else
+            PREV_COMMIT=$(git rev-parse HEAD)  # Fallback to the current commit if there's no previous commit
+          fi
+          CURRENT_COMMIT=$(git rev-parse HEAD)
+          LAST_MAIN_COMMIT=$(git rev-parse origin/main)
+          echo "Benchmarking current commit ($CURRENT_COMMIT) against $PREV_COMMIT"
+          benchpkg --rev="$LAST_MAIN_COMMIT,$CURRENT_COMMIT" --bench-on="$CURRENT_COMMIT" --output-dir=results/ --tune
+        
+      - name: Generate and Upload Benchmark Plots
+        run: |
+          mkdir -p plots
+          LAST_MAIN_COMMIT=$(git rev-parse origin/main)
+          CURRENT_COMMIT=$(git rev-parse HEAD)
+          echo "Generating plots comparing CURRENT_COMMIT ($CURRENT_COMMIT) with LAST_MAIN_COMMIT ($LAST_MAIN_COMMIT)"
+          benchpkgplot --rev="$LAST_MAIN_COMMIT,$CURRENT_COMMIT" --npart=10 --format=png --input-dir=results/ --output-dir=plots/
+        if: always()
+      
       - name: Upload Plots as Artifacts
         uses: actions/upload-artifact@v4
         with:
           name: benchmark-plots
           path: plots
-
+        
       - name: Create and Display Benchmark Table
         run: |
-          git fetch origin main:refs/remotes/origin/main  # Ensures you have the latest main branch
+          mkdir -p results
           if [ $(git rev-list --count HEAD) -gt 1 ]; then
             PREV_COMMIT=$(git rev-parse HEAD^1)
           else
-            PREV_COMMIT=$(git rev-parse HEAD)  # Fallback to the current commit if there's no previous commit
+            PREV_COMMIT=$(git rev-parse HEAD)  # Use the current commit as a fallback
           fi
-          LAST_MAIN_COMMIT=$(git rev-parse origin/main)  # Ensures comparison against the latest commit in main
-          echo "Using revisions: $LAST_MAIN_COMMIT and $PREV_COMMIT for benchmark comparison."
+          LAST_MAIN_COMMIT=$(git rev-parse origin/main)  # Fetch the latest commit from main for comparison
+          echo "Creating benchmark table comparing CURRENT_COMMIT with LAST_MAIN_COMMIT"
           benchpkgtable --rev="$LAST_MAIN_COMMIT,$PREV_COMMIT" --input-dir=results/ > table.md
           echo '### Benchmark Results' > body.md
           cat table.md >> body.md
           echo '### Benchmark Plots' >> body.md
           echo 'A plot of the benchmark results has been uploaded as an artifact to this workflow run.' >> body.md
           cat body.md  # Print the markdown table to the log for review.
         if: always()
-
+        
       - name: Upload Benchmark Results Table
         uses: actions/upload-artifact@v4
         with: