Add option --experimental_discard_actions_after_execution in order to turn it off after a release.

Discarding actions hasn't been shown to have a significant positive effect on heap memory usage, after careful research by mschaller@. It's holding back other projects (threading Fileset metadata through) and adding complexity, so it's time to kill it. Out of an abundance of caution, I'll keep actions in memory via a flag flip, then, if it sticks, I'll change the default, and then I'll unwire everything.

PiperOrigin-RevId: 196682768

1 files changed, 4 insertions, 1 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SequencedSkyframeExecutor.java b/src/main/java/com/google/devtools/build/lib/skyframe/SequencedSkyframeExecutor.java
index e63ae0913d..aaeed3f73f 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SequencedSkyframeExecutor.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SequencedSkyframeExecutor.java
@@ -612,12 +612,15 @@ public final class SequencedSkyframeExecutor extends SkyframeExecutor {
       }
     }
 
+    removeActionsAfterEvaluation.set(
+        !trackIncrementalState
+            && requestOptions != null
+            && requestOptions.discardActionsAfterExecution);
     // Now check if it is necessary to wipe the previous state. We do this if either the previous
     // or current incrementalStateRetentionStrategy requires the build to have been isolated.
     if (oldValueOfTrackIncrementalState != trackIncrementalState) {
       logger.info("Set incremental state to " + trackIncrementalState);
       evaluatorNeedsReset = true;
-      removeActionsAfterEvaluation.set(!trackIncrementalState);
     } else if (!trackIncrementalState) {
       evaluatorNeedsReset = true;
     }