Add getMaxTransitiveSourceVersionToInjectForNonHermeticFunction to …

…`SkyFunction`, which returns the max transitive source version (mtsv) that could be injected via `SkyFunctionEnvironment#injectVersionForNonHermeticFunction` if `#compute` were invoked for a `SkyKey`/`SkyValue` pair, or null if no call for version injection is made.

PiperOrigin-RevId: 526996521
Change-Id: Ie99c41a452e3c67ae9a60546164cafaaac54cc7f

src/main/java/com/google/devtools/build/skyframe/SkyFunction.java

@@ -13,6 +13,8 @@
 // limitations under the License.
 package com.google.devtools.build.skyframe;
 
+import static com.google.common.base.Preconditions.checkState;
+
 import com.google.common.base.Preconditions;
 import com.google.common.graph.GraphBuilder;
 import com.google.common.graph.ImmutableGraph;
@@ -21,6 +23,7 @@
 import com.google.devtools.build.lib.events.ExtendedEventHandler;
 import com.google.devtools.build.lib.events.Reportable;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import java.io.IOException;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Supplier;
 import javax.annotation.Nullable;
@@ -84,6 +87,19 @@ default String extractTag(SkyKey skyKey) {
     return null;
   }
 
+  /**
+   * Returns the max transitive source version that would be injected via {@link
+   * SkyFunctionEnvironment#injectVersionForNonHermeticFunction} if {@link #compute(SkyKey,
+   * Environment)} were invoked for the given {@link SkyKey}/{@link SkyValue} pair, or null if no
+   * call for version injection would be made.
+   */
+  @Nullable
+  default Version getMaxTransitiveSourceVersionToInjectForNonHermeticFunction(
+      SkyKey skyKey, SkyValue skyValue) throws IOException {
+    checkState(skyKey.functionName().getHermeticity() == FunctionHermeticity.HERMETIC);
+    return null;
+  }
+
   /**
    * Sentinel {@link SkyValue} type for {@link #compute} to return, indicating that something went
    * wrong, and that the evaluation returning this value must be restarted, and the nodes associated