Flip the default value of --experimental_remote_discard_merkle_trees …

…to true

Closes #19941.

PiperOrigin-RevId: 576939270
Change-Id: Iafe4eb6d885e339db52ff2b496bd0a571ec6609d

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

@@ -653,7 +653,7 @@ public RemoteOutputsStrategyConverter() {
 
   @Option(
       name = "experimental_remote_discard_merkle_trees",
-      defaultValue = "false",
+      defaultValue = "true",
       documentationCategory = OptionDocumentationCategory.REMOTE,
       effectTags = {OptionEffectTag.UNKNOWN},
       help =

src/test/java/com/google/devtools/build/lib/remote/RemoteExecutionServiceTest.java

@@ -2186,6 +2186,7 @@ public void buildRemoteActionForRemotePersistentWorkers() throws Exception {
             .build();
     FakeSpawnExecutionContext context = newSpawnExecutionContext(spawn);
     remoteOptions.markToolInputs = true;
+    remoteOptions.remoteDiscardMerkleTrees = false;
     RemoteExecutionService service = newRemoteExecutionService(remoteOptions);
 
     // Check that worker files are properly marked in the merkle tree.
@@ -2277,6 +2278,7 @@ public void buildRemoteActionWithScrubbing() throws Exception {
                                         .setSource("some/path")
                                         .setTarget("another/dir"))))
                 .build());
+    remoteOptions.remoteDiscardMerkleTrees = false;
     RemoteExecutionService service = newRemoteExecutionService(remoteOptions);
 
     RemoteAction remoteAction = service.buildRemoteAction(spawn, context);
@@ -2332,6 +2334,7 @@ public void buildRemoteActionWithPathMapping(@TestParameter boolean remoteMerkle
             .setPathMapper(pathMapper)
             .build();
     FakeSpawnExecutionContext context = newSpawnExecutionContext(spawn);
+    remoteOptions.remoteDiscardMerkleTrees = false;
     RemoteExecutionService service = newRemoteExecutionService(remoteOptions);
 
     // Check that inputs and outputs of the remote action are mapped correctly.

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

@@ -2338,8 +2338,8 @@ function test_empty_tree_artifact_as_inputs() {
   bazel build \
     --spawn_strategy=remote \
     --remote_executor=grpc://localhost:${worker_port} \
-    --experimental_remote_discard_merkle_trees \
-    //pkg:a &>$TEST_log || fail "expected build to succeed with Merkle tree discarding"
+    --experimental_remote_discard_merkle_trees=false \
+    //pkg:a &>$TEST_log || fail "expected build to succeed without Merkle tree discarding"
 
   bazel clean --expunge
   bazel build \
@@ -2419,8 +2419,8 @@ function test_create_tree_artifact_outputs() {
   bazel build \
     --spawn_strategy=remote \
     --remote_executor=grpc://localhost:${worker_port} \
-    --experimental_remote_discard_merkle_trees \
-    //pkg:a &>$TEST_log || fail "expected build to succeed with Merkle tree discarding"
+    --experimental_remote_discard_merkle_trees=false \
+    //pkg:a &>$TEST_log || fail "expected build to succeed without Merkle tree discarding"
   [[ -f bazel-bin/pkg/a/non_empty_dir/out ]] || fail "expected tree artifact to contain a file"
   [[ -d bazel-bin/pkg/a/empty_dir ]] || fail "expected directory to exist"
 
@@ -3180,8 +3180,8 @@ EOF
     build \
     --spawn_strategy=remote \
     --remote_executor=grpc://localhost:${worker_port} \
-    --experimental_remote_discard_merkle_trees \
-    //pkg:b &>$TEST_log || fail "expected build to succeed with Merkle tree discarding"
+    --experimental_remote_discard_merkle_trees=false \
+    //pkg:b &>$TEST_log || fail "expected build to succeed without Merkle tree discarding"
 
   if [[ "$(cat bazel-bin/pkg/b.txt)" != "$link_target" ]]; then
     fail "expected symlink target to be $link_target"