CI guard: run demo config natively under cmd, tolerate already-configured

The first version of the guard reused the cluster start-opensearch had
already configured, so the installer hit 'already configured for Security.
Quit.' and exited -1 (its exit code equals skip_updates, which -i/-c leave
at -1). Pass -s so an already-configured opensearch.yml exits 0, while a
home-discovery failure still exits non-zero from setBaseDir - which is the
condition this guard is meant to catch.

Signed-off-by: Craig Perkins <cwperks@amazon.com>

Author: Craig Perkins

.github/workflows/plugin_install.yml

@@ -67,30 +67,28 @@ jobs:
           admin-password: ${{ steps.generate-password.outputs.password }}
           jdk-version: 21
 
-      - name: Verify demo configuration script locates OpenSearch home on Windows
+      - name: Verify demo config script locates OpenSearch home on Windows
         # Regression guard for #6023: the tools/*.bat parent-directory walk used
         # %~dpI on a path ending in "\." which does not ascend, so the script
-        # exited non-zero and OpenSearch failed to start on Windows with no error
-        # output. This runs the script natively under cmd.exe (the real startup
-        # environment, unlike the bash-invoked path in start-opensearch) and
-        # asserts a zero exit code and that OPENSEARCH_HOME resolved to a dir
-        # containing lib/opensearch-*.jar.
+        # exited non-zero and OpenSearch failed to start on Windows with no
+        # error output. Run the script natively under cmd.exe (unlike the
+        # bash-invoked path in start-opensearch), with OPENSEARCH_HOME unset so
+        # the home-discovery loop is exercised. The -s flag makes an
+        # already-configured opensearch.yml a benign exit 0 (start-opensearch
+        # already ran the installer), while a home-discovery failure still
+        # exits non-zero from setBaseDir - which is exactly what we guard.
         if: ${{ runner.os == 'Windows' }}
         shell: cmd
         run: |
           set "OS_DIR=opensearch-${{ env.OPENSEARCH_VERSION }}-SNAPSHOT9200"
-          if not exist "%OS_DIR%\plugins\opensearch-security\tools\install_demo_configuration.bat" (
-            echo Demo script not found under %OS_DIR% 1>&2
-            exit /b 1
-          )
-          rem Run with OPENSEARCH_HOME unset so the home-discovery loop is exercised.
           set "OPENSEARCH_HOME="
-          call "%OS_DIR%\plugins\opensearch-security\tools\install_demo_configuration.bat" -y -i -c
-          if errorlevel 1 (
-            echo install_demo_configuration.bat exited with a non-zero code 1>&2
+          call "%OS_DIR%\plugins\opensearch-security\tools\install_demo_configuration.bat" -y -i -c -s
+          set "RC=%errorlevel%"
+          if not "%RC%" == "0" (
+            echo install_demo_configuration.bat exited with code %RC% - home discovery failed 1>&2
             exit /b 1
           )
-          echo Demo configuration script completed with exit code 0
+          echo Home discovery succeeded on Windows (exit 0)
 
       - name: Run sanity tests
         run: ./gradlew integTestRemote -Dtests.rest.cluster=localhost:9200 -Dtests.cluster=localhost:9200 -Dtests.clustername="opensearch" -Dhttps=true -Duser=admin "-Dpassword=${SECURITY_PASSWORD}" -i