chore: fix multiline output

Signed-off-by: Justin Chadwell <me@jedevc.com>

.github/workflows/test.yml

@@ -28,7 +28,7 @@ jobs:
         with:
           version: latest
           verb: core
-          args: container from --address=alpine with-exec --args echo,"hello world" stdout
+          args: container from --address=alpine with-exec --args echo,-n,"hello world" stdout
       - name: "Use output (check)"
         run: |
           target='${{ steps.use-output.outputs.output }}'
@@ -40,13 +40,33 @@ jobs:
             exit 1
           fi
 
+      - name: "Use trailing output"
+        id: use-trailing-output
+        uses: ./
+        with:
+          version: latest
+          verb: core
+          args: container from --address=alpine with-exec --args echo,-n,-e,"hello world\n" stdout
+      - name: "Use output (check)"
+        run: |
+          target='${{ steps.use-trailing-output.outputs.output }}'
+          result='hello world
+          '
+          if [[ "$target" == "$result" ]]; then
+            echo "matches"
+            exit 0
+          else
+            echo "does not match"
+            exit 1
+          fi
+
       - name: "Use multiline output"
         id: use-multiline-output
         uses: ./
         with:
           version: latest
           verb: core
-          args: container from --address=alpine with-exec --args echo,-e,"hello\nworld" stdout
+          args: container from --address=alpine with-exec --args echo,-n,-e,"hello\nworld" stdout
       - name: "Use output (check)"
         run: |
           target='${{ steps.use-multiline-output.outputs.output }}'

action.yml

@@ -83,7 +83,16 @@ runs:
         ${INPUT_MODULE:+-m $INPUT_MODULE} \
         ${{ inputs.args }}; } | tee "${tmpout}"
 
-        (echo -n "stdout=" && cat "${tmpout}") >> "$GITHUB_OUTPUT"
+        {
+          # we need a delim that doesn't appear in the output - a hash of the
+          # file itself *probably* won't (if it does, we have larger
+          # cryptographic problems)
+          delim="$(sha256sum $tmpout | cut -d " " -f1)"
+          echo "stdout<<${delim}"
+          cat "${tmpout}"
+          echo
+          echo "${delim}"
+        } >> "$GITHUB_OUTPUT"
 
     - if: inputs.engine-stop == 'true'
       shell: bash