diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ProgressEventSuppressingEnvironment.java b/src/main/java/com/google/devtools/build/lib/skyframe/ProgressEventSuppressingEnvironment.java
index c1d08fba536d52..b8cc148b6b3120 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ProgressEventSuppressingEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ProgressEventSuppressingEnvironment.java
@@ -146,4 +146,10 @@ public boolean restartPermitted() {
   public <T extends SkyKeyComputeState> T getState(Supplier<T> stateSupplier) {
     return delegate.getState(stateSupplier);
   }
+
+  @Override
+  @Nullable
+  public Version getMaxTransitiveSourceVersionSoFar() {
+    return delegate.getMaxTransitiveSourceVersionSoFar();
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SkyFunctionEnvironmentForTesting.java b/src/main/java/com/google/devtools/build/lib/skyframe/SkyFunctionEnvironmentForTesting.java
index 98b48a473e3968..d3f523b75cf37c 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SkyFunctionEnvironmentForTesting.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SkyFunctionEnvironmentForTesting.java
@@ -28,9 +28,11 @@
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
 import com.google.devtools.build.skyframe.ValueOrUntypedException;
+import com.google.devtools.build.skyframe.Version;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
+import javax.annotation.Nullable;
 
 /**
  * A {@link SkyFunction.Environment} backed by a {@link SkyframeExecutor} that can be used to
@@ -101,4 +103,10 @@ public boolean restartPermitted() {
   public <T extends SkyKeyComputeState> T getState(Supplier<T> stateSupplier) {
     return stateSupplier.get();
   }
+
+  @Override
+  @Nullable
+  public Version getMaxTransitiveSourceVersionSoFar() {
+    throw new UnsupportedOperationException();
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/StateInformingSkyFunctionEnvironment.java b/src/main/java/com/google/devtools/build/lib/skyframe/StateInformingSkyFunctionEnvironment.java
index 27cf411737d72b..b0b989d1b7e406 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/StateInformingSkyFunctionEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/StateInformingSkyFunctionEnvironment.java
@@ -181,4 +181,10 @@ public <T extends SkyKeyComputeState> T getState(Supplier<T> stateSupplier) {
   interface Informee {
     void inform() throws InterruptedException;
   }
+
+  @Override
+  @Nullable
+  public Version getMaxTransitiveSourceVersionSoFar() {
+    return delegate.getMaxTransitiveSourceVersionSoFar();
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/skyframe/RecordingSkyFunctionEnvironment.java b/src/main/java/com/google/devtools/build/skyframe/RecordingSkyFunctionEnvironment.java
index 8d8eccfeea5925..c24f1328ece210 100644
--- a/src/main/java/com/google/devtools/build/skyframe/RecordingSkyFunctionEnvironment.java
+++ b/src/main/java/com/google/devtools/build/skyframe/RecordingSkyFunctionEnvironment.java
@@ -200,4 +200,10 @@ public boolean restartPermitted() {
   public <T extends SkyKeyComputeState> T getState(Supplier<T> stateSupplier) {
     return delegate.getState(stateSupplier);
   }
+
+  @Override
+  @Nullable
+  public Version getMaxTransitiveSourceVersionSoFar() {
+    return delegate.getMaxTransitiveSourceVersionSoFar();
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/skyframe/SkyFunction.java b/src/main/java/com/google/devtools/build/skyframe/SkyFunction.java
index 2245d6cacc688d..f941c6e81272ca 100644
--- a/src/main/java/com/google/devtools/build/skyframe/SkyFunction.java
+++ b/src/main/java/com/google/devtools/build/skyframe/SkyFunction.java
@@ -409,5 +409,14 @@ interface SkyKeyComputeState {}
      * {@link #compute} call.
      */
     <T extends SkyKeyComputeState> T getState(Supplier<T> stateSupplier);
+
+    /**
+     * Returns the max transitive source version of a {@link NodeEntry}.
+     *
+     * <p>This value might not consider all deps' source versions if called before all deps have
+     * been requested or if {@link #valuesMissing()} returns true.
+     */
+    @Nullable
+    Version getMaxTransitiveSourceVersionSoFar();
   }
 }
diff --git a/src/main/java/com/google/devtools/build/skyframe/SkyFunctionEnvironment.java b/src/main/java/com/google/devtools/build/skyframe/SkyFunctionEnvironment.java
index 610945dcf33439..5c463a0ef3cb0a 100644
--- a/src/main/java/com/google/devtools/build/skyframe/SkyFunctionEnvironment.java
+++ b/src/main/java/com/google/devtools/build/skyframe/SkyFunctionEnvironment.java
@@ -994,4 +994,10 @@ ImmutableList<SkyKey> getDepKeys() {
       return depKeys;
     }
   }
+
+  @Override
+  @Nullable
+  public Version getMaxTransitiveSourceVersionSoFar() {
+    return maxTransitiveSourceVersion;
+  }
 }
diff --git a/src/test/java/com/google/devtools/build/lib/actions/util/ActionsTestUtil.java b/src/test/java/com/google/devtools/build/lib/actions/util/ActionsTestUtil.java
index 5d48dfe0b1776e..d93437767821fc 100644
--- a/src/test/java/com/google/devtools/build/lib/actions/util/ActionsTestUtil.java
+++ b/src/test/java/com/google/devtools/build/lib/actions/util/ActionsTestUtil.java
@@ -104,6 +104,7 @@
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
 import com.google.devtools.build.skyframe.ValueOrUntypedException;
+import com.google.devtools.build.skyframe.Version;
 import com.google.protobuf.ByteString;
 import java.io.IOException;
 import java.io.OutputStream;
@@ -399,6 +400,12 @@ public boolean restartPermitted() {
     public <T extends SkyKeyComputeState> T getState(Supplier<T> stateSupplier) {
       return stateSupplier.get();
     }
+
+    @Override
+    @Nullable
+    public Version getMaxTransitiveSourceVersionSoFar() {
+      throw new UnsupportedOperationException();
+    }
   }
 
   @SerializationConstant