1 files changed, 5 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/FilesystemValueChecker.java b/src/main/java/com/google/devtools/build/lib/skyframe/FilesystemValueChecker.java
index c99898028a..b501f3abce 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/FilesystemValueChecker.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/FilesystemValueChecker.java
@@ -43,6 +43,7 @@ import com.google.devtools.build.lib.vfs.ModifiedFileSet;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.skyframe.Differencer;
+import com.google.devtools.build.skyframe.FunctionHermeticity;
 import com.google.devtools.build.skyframe.SkyFunctionName;
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
@@ -506,6 +507,10 @@ public class FilesystemValueChecker {
         if (!checker.applies(key)) {
           continue;
         }
+        Preconditions.checkState(
+            key.functionName().getHermeticity() == FunctionHermeticity.NONHERMETIC,
+            "Only non-hermetic keys can be dirty roots: %s",
+            key);
         executor.execute(
             wrapper.wrap(
                 () -> {