action rewinding: recover lost CAS blobs

app/buck2_action_impl/src/actions/impls/run.rs

@@ -1076,9 +1076,14 @@ impl RunAction {
         // First, check in the local dep file cache if an identical action can be found there.
         // Do this before checking the action cache as we can avoid a potentially large download.
         // Once the action cache lookup misses, we will do the full dep file cache look up.
-        let (outputs, should_fully_check_dep_file_cache) = dep_file_bundle
-            .check_local_dep_file_cache_for_identical_action(ctx, self.outputs.as_slice())
-            .await?;
+        let should_bypass_action_cache = ctx.should_bypass_action_cache();
+        let (outputs, should_fully_check_dep_file_cache) = if should_bypass_action_cache {
+            (None, false)
+        } else {
+            dep_file_bundle
+                .check_local_dep_file_cache_for_identical_action(ctx, self.outputs.as_slice())
+                .await?
+        };
         if let Some((outputs, metadata)) = outputs {
             return Ok(ExecuteResult::LocalDepFileHit(outputs, metadata));
         }
@@ -1541,7 +1546,8 @@ impl Action for RunAction {
         waiting_data: WaitingData,
     ) -> Result<(ActionOutputs, ActionExecutionMetadata), ExecuteError> {
         // Check offline cache first if parameter enabled
-        if self.inner.allow_offline_output_cache
+        if !ctx.should_bypass_action_cache()
+            && self.inner.allow_offline_output_cache
             && ctx.run_action_knobs().use_network_action_output_cache
         {
             if let Some((outputs, metadata)) = self.execute_for_offline(ctx).await? {

app/buck2_build_api/src/actions.rs

@@ -97,6 +97,7 @@ pub mod execute;
 pub mod impls;
 pub mod query;
 pub mod registry;
+pub mod rewind;
 
 /// Represents an unregistered 'Action' that will be registered into the 'Actions' module.
 /// The 'UnregisteredAction' is not executable until it is registered, upon which it becomes an
@@ -286,6 +287,10 @@ pub trait ActionExecutionCtx: Send + Sync {
         prepared_action: &PreparedAction,
     ) -> ControlFlow<CommandExecutionResult, CommandExecutionManager>;
 
+    fn should_bypass_action_cache(&self) -> bool {
+        false
+    }
+
     async fn cache_upload(
         &mut self,
         action: &ActionDigestAndBlobs,