Minor simple optimization in FileFunction: don't bother getting a FileStateValue for a path realpath 'parent/child' if 'parent' is known to not exist. This saves a stat for each ancestor path.

--
MOS_MIGRATED_REVID=102881929

2 files changed, 6 insertions, 3 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/FileFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/FileFunction.java
index 32cce31b85..bec8ed358e 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/FileFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/FileFunction.java
@@ -145,6 +145,9 @@ public class FileFunction implements SkyFunction {
       RootedPath parentRealRootedPath = parentFileValue.realRootedPath();
       realRootedPath = RootedPath.toRootedPath(parentRealRootedPath.getRoot(),
           parentRealRootedPath.getRelativePath().getRelative(baseName));
+      if (!parentFileValue.exists()) {
+        return Pair.of(realRootedPath, FileStateValue.NONEXISTENT_FILE_STATE_NODE);
+      }
     }
     FileStateValue realFileStateValue =
         (FileStateValue) env.getValue(FileStateValue.key(realRootedPath));
@@ -155,7 +158,7 @@ public class FileFunction implements SkyFunction {
         && parentFileValue != null && !parentFileValue.isDirectory()) {
       String type = realFileStateValue.getType().toString().toLowerCase();
       String message = type + " " + rootedPath.asPath() + " exists but its parent "
-          + "directory " + parentFileValue.realRootedPath().asPath() + " doesn't exist.";
+          + "path " + parentFileValue.realRootedPath().asPath() + " isn't an existing directory.";
       throw new FileFunctionException(new InconsistentFilesystemException(message),
           Transience.TRANSIENT);
     }
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/FileStateValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/FileStateValue.java
index 3d06d7c01f..0be5c318c6 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/FileStateValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/FileStateValue.java
@@ -175,8 +175,8 @@ public abstract class FileStateValue implements SkyValue {
         String errorMessage = e.getMessage() != null
             ? "error '" + e.getMessage() + "'" : "an error";
         throw new InconsistentFilesystemException("'stat' said " + path + " is a file but then we "
-            + "later encountered " + errorMessage + " which indicates that " + path + " no longer "
-            + "exists. Did you delete it during the build?");
+            + "later encountered " + errorMessage + " which indicates that " + path + " is no "
+            + "longer a file. Did you delete it during the build?");
       }
     }