Add experimental_ prefix

src/main/java/com/google/devtools/build/lib/remote/RemoteSpawnRunner.java

@@ -240,7 +240,7 @@ public SpawnResult exec(Spawn spawn, SpawnExecutionContext context)
       return new SpawnResult.Builder()
           .setStatus(SpawnResult.Status.EXECUTION_DENIED)
           .setExitCode(1)
-          .setFailureMessage("Action must be cached due to --remote_require_cached but it is not")
+          .setFailureMessage("Action must be cached due to --experimental_remote_require_cached but it is not")
           .setFailureDetail(
               FailureDetail.newBuilder()
                   .setSpawn(FailureDetails.Spawn.newBuilder().setCode(FailureDetails.Spawn.Code.EXECUTION_DENIED))

src/main/java/com/google/devtools/build/lib/remote/options/RemoteOptions.java

@@ -230,7 +230,7 @@ public final class RemoteOptions extends CommonRemoteOptions {
   public boolean remoteAcceptCached;
 
   @Option(
-      name = "remote_require_cached",
+      name = "experimental_remote_require_cached",
       defaultValue = "false",
       documentationCategory = OptionDocumentationCategory.REMOTE,
       effectTags = {OptionEffectTag.UNKNOWN},

src/test/shell/bazel/remote/remote_execution_test.sh

@@ -1284,12 +1284,12 @@ EOF
   echo "input 2" >a/foo.in
   if bazel build \
     --remote_executor=grpc://localhost:${worker_port} \
-    --remote_require_cached \
+    --experimental_remote_require_cached \
     //a:foo >& $TEST_log; then
     fail "Build of //a:foo succeeded but it should have failed"
   fi
 
-  expect_log "Action must be cached due to --remote_require_cached but it is not"
+  expect_log "Action must be cached due to --experimental_remote_require_cached but it is not"
   expect_not_log "remote cache hit"
 }