Fix: GITHUB_PATH should prepend (#690)

* GITHUB_PATH is prepend

https://docs.github.com/en/actions/reference/workflow-commands-for-github-actions#adding-a-system-path

* Check for replacing system binaries

Co-authored-by: Josh Soref <jsoref@users.noreply.github.com>

pkg/container/docker_run.go

@@ -399,7 +399,7 @@ func (cr *containerReference) extractPath(env *map[string]string) common.Executo
 		s := bufio.NewScanner(reader)
 		for s.Scan() {
 			line := s.Text()
-			localEnv["PATH"] = fmt.Sprintf("%s:%s", localEnv["PATH"], line)
+			localEnv["PATH"] = fmt.Sprintf("%s:%s", line, localEnv["PATH"])
 		}
 
 		env = &localEnv

pkg/runner/testdata/env-and-path/push.yaml

@@ -13,10 +13,30 @@ jobs:
           echo "$HOME/someOtherFolder" >> $GITHUB_PATH
       - name: "Check PATH"
         run: |
-          if [[ ! "${PATH}" =~ .*"$HOME/"someFolder.*"$HOME/"someOtherFolder ]]; then
-            echo "${PATH} doesn't match .*someFolder.*someOtherFolder"
+          echo "${PATH}"
+          if [[ ! "${PATH}" =~ .*"$HOME/"someOtherFolder.*"$HOME/"someFolder.* ]]; then
+            echo "${PATH} doesn't match .*someOtherFolder.*someFolder.*"
             exit 1
           fi
+      - name: "Prepend"
+        run: |
+          if ls | grep -q 'called ls' ; then
+            echo 'ls was overridden already?'
+            exit 2
+          fi
+          path_add=$(mktemp -d)
+          cat > $path_add/ls <<LS
+          #!/bin/sh
+          echo 'called ls'
+          LS
+          chmod +x $path_add/ls
+          echo $path_add >> $GITHUB_PATH
+      - name: "Verify prepend"
+        run: |
+          if ! ls | grep -q 'called ls' ; then
+            echo 'ls was not overridden'
+            exit 2
+          fi
       - name: "Write single line env to $GITHUB_ENV"
         run: |
           echo "KEY=value" >> $GITHUB_ENV