Tell remote execution to not use remote cache internally (#17198)

Closes #17142.

We rely on the RemoteCache command runner for caching with remote execution. We always disable remote servers from doing caching themselves not only to avoid wasted work, but more importantly because they do not have our same caching semantics, e.g. `ProcessCacheScope.SUCCESSFUL` vs `ProcessCacheScope.ALWAYS`.

src/rust/engine/process_execution/src/remote.rs

@@ -1010,6 +1010,11 @@ pub fn make_execute_request(
   let execute_request = remexec::ExecuteRequest {
     action_digest: Some((&digest(&action)?).into()),
     instance_name: instance_name.unwrap_or_else(|| "".to_owned()),
+    // We rely on the RemoteCache command runner for caching with remote execution. We always
+    // disable remote servers from doing caching themselves not only to avoid wasted work, but
+    // more importantly because they do not have our same caching semantics, e.g.
+    // `ProcessCacheScope.SUCCESSFUL` vs `ProcessCacheScope.ALWAYS`.
+    skip_cache_lookup: true,
     ..remexec::ExecuteRequest::default()
   };
 

src/rust/engine/process_execution/src/remote_tests.rs

@@ -137,6 +137,7 @@ async fn make_execute_request() {
       ))
         .into(),
     ),
+    skip_cache_lookup: true,
     ..Default::default()
   };
 
@@ -225,6 +226,7 @@ async fn make_execute_request_with_instance_name() {
       ))
         .into(),
     ),
+    skip_cache_lookup: true,
     ..Default::default()
   };
 
@@ -311,6 +313,7 @@ async fn make_execute_request_with_cache_key_gen_version() {
       ))
         .into(),
     ),
+    skip_cache_lookup: true,
     ..Default::default()
   };
 
@@ -370,6 +373,7 @@ async fn make_execute_request_with_jdk() {
       ))
         .into(),
     ),
+    skip_cache_lookup: true,
     ..Default::default()
   };
 
@@ -453,6 +457,7 @@ async fn make_execute_request_with_jdk_and_extra_platform_properties() {
       ))
         .into(),
     ),
+    skip_cache_lookup: true,
     ..Default::default()
   };
 
@@ -533,6 +538,7 @@ async fn make_execute_request_with_timeout() {
       ))
         .into(),
     ),
+    skip_cache_lookup: true,
     ..Default::default()
   };
 
@@ -639,6 +645,7 @@ async fn make_execute_request_using_immutable_inputs() {
       ))
         .into(),
     ),
+    skip_cache_lookup: true,
     ..Default::default()
   };