Move some IO-focused classes that don't have deps on other parts of Bazel to the new lib/io package. Also, couldn't resist some clean-ups on Abstract(File)ChainUniquenessFunction: was only used for RootedPath, so specialized to that, and streamlined the uniquifier a bit, hopefully without any bugs that our test battery won't catch. I did debate truly uniquifying the cycle by breaking ties based on the next element, but managed to back away. PiperOrigin-RevId: 363756543

diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/FileSymlinkCycleUniquenessFunctionTest.java b/src/test/java/com/google/devtools/build/lib/io/FileSymlinkCycleUniquenessFunctionTest.java
similarity index 94%
rename from src/test/java/com/google/devtools/build/lib/skyframe/FileSymlinkCycleUniquenessFunctionTest.java
rename to src/test/java/com/google/devtools/build/lib/io/FileSymlinkCycleUniquenessFunctionTest.java
index 24835fe..678445b 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/FileSymlinkCycleUniquenessFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/io/FileSymlinkCycleUniquenessFunctionTest.java

@@ -11,7 +11,7 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-package com.google.devtools.build.lib.skyframe;
+package com.google.devtools.build.lib.io;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.testing.EqualsTester;
@@ -26,9 +26,8 @@
 
 @RunWith(JUnit4.class)
 public class FileSymlinkCycleUniquenessFunctionTest {
-
   @Test
-  public void testHashCodeAndEqualsContract() throws Exception {
+  public void testHashCodeAndEqualsContract() {
     Root root = Root.fromPath(new InMemoryFileSystem(DigestHashFunction.SHA256).getPath("/root"));
     RootedPath p1 = RootedPath.toRootedPath(root, PathFragment.create("p1"));
     RootedPath p2 = RootedPath.toRootedPath(root, PathFragment.create("p2"));

diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/BUILD b/src/test/java/com/google/devtools/build/lib/skyframe/BUILD
index 8667c03..2c858f9 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/BUILD

@@ -196,10 +196,10 @@
         "//src/main/java/com/google/devtools/build/lib/skyframe:directory_listing_function",
         "//src/main/java/com/google/devtools/build/lib/skyframe:directory_listing_state_value",
         "//src/main/java/com/google/devtools/build/lib/skyframe:file_function",
-        "//src/main/java/com/google/devtools/build/lib/skyframe:file_symlink_cycle_exception",
-        "//src/main/java/com/google/devtools/build/lib/skyframe:file_symlink_cycle_uniqueness_function",
-        "//src/main/java/com/google/devtools/build/lib/skyframe:file_symlink_infinite_expansion_exception",
-        "//src/main/java/com/google/devtools/build/lib/skyframe:file_symlink_infinite_expansion_uniqueness_function",
+        "//src/main/java/com/google/devtools/build/lib/io:file_symlink_cycle_exception",
+        "//src/main/java/com/google/devtools/build/lib/io:file_symlink_cycle_uniqueness_function",
+        "//src/main/java/com/google/devtools/build/lib/io:file_symlink_infinite_expansion_exception",
+        "//src/main/java/com/google/devtools/build/lib/io:file_symlink_infinite_expansion_uniqueness_function",
         "//src/main/java/com/google/devtools/build/lib/skyframe:fileset_entry_function",
         "//src/main/java/com/google/devtools/build/lib/skyframe:fileset_entry_key",
         "//src/main/java/com/google/devtools/build/lib/skyframe:fileset_entry_value",

diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/ContainingPackageLookupFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/ContainingPackageLookupFunctionTest.java
index c687dbb..b68a2f3 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/ContainingPackageLookupFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/ContainingPackageLookupFunctionTest.java

@@ -27,6 +27,7 @@
 import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
 import com.google.devtools.build.lib.events.NullEventHandler;
+import com.google.devtools.build.lib.io.FileSymlinkCycleUniquenessFunction;
 import com.google.devtools.build.lib.packages.RuleClassProvider;
 import com.google.devtools.build.lib.packages.WorkspaceFileValue;
 import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
@@ -144,7 +145,7 @@
         SkyFunctions.LOCAL_REPOSITORY_LOOKUP,
         new LocalRepositoryLookupFunction(BazelSkyframeExecutorConstants.EXTERNAL_PACKAGE_HELPER));
     skyFunctions.put(
-        SkyFunctions.FILE_SYMLINK_CYCLE_UNIQUENESS, new FileSymlinkCycleUniquenessFunction());
+        FileSymlinkCycleUniquenessFunction.NAME, new FileSymlinkCycleUniquenessFunction());
     ImmutableMap<String, RepositoryFunction> repositoryHandlers =
         ImmutableMap.of(
             LocalRepositoryRule.NAME, (RepositoryFunction) new LocalRepositoryFunction());

diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/FileFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/FileFunctionTest.java
index 92c7dcc..725e5af 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/FileFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/FileFunctionTest.java

@@ -43,6 +43,10 @@
 import com.google.devtools.build.lib.cmdline.LabelConstants;
 import com.google.devtools.build.lib.events.NullEventHandler;
 import com.google.devtools.build.lib.events.StoredEventHandler;
+import com.google.devtools.build.lib.io.FileSymlinkCycleException;
+import com.google.devtools.build.lib.io.FileSymlinkCycleUniquenessFunction;
+import com.google.devtools.build.lib.io.FileSymlinkInfiniteExpansionException;
+import com.google.devtools.build.lib.io.FileSymlinkInfiniteExpansionUniquenessFunction;
 import com.google.devtools.build.lib.io.InconsistentFilesystemException;
 import com.google.devtools.build.lib.packages.WorkspaceFileValue;
 import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
@@ -162,10 +166,10 @@
                         new AtomicReference<>(UnixGlob.DEFAULT_SYSCALLS),
                         externalFilesHelper))
                 .put(
-                    SkyFunctions.FILE_SYMLINK_CYCLE_UNIQUENESS,
+                    FileSymlinkCycleUniquenessFunction.NAME,
                     new FileSymlinkCycleUniquenessFunction())
                 .put(
-                    SkyFunctions.FILE_SYMLINK_INFINITE_EXPANSION_UNIQUENESS,
+                    FileSymlinkInfiniteExpansionUniquenessFunction.NAME,
                     new FileSymlinkInfiniteExpansionUniquenessFunction())
                 .put(FileValue.FILE, new FileFunction(pkgLocatorRef))
                 .put(

diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTest.java
index e6c792e..8b54594 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTest.java

@@ -41,6 +41,8 @@
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.events.NullEventHandler;
+import com.google.devtools.build.lib.io.FileSymlinkCycleUniquenessFunction;
+import com.google.devtools.build.lib.io.FileSymlinkInfiniteExpansionUniquenessFunction;
 import com.google.devtools.build.lib.packages.WorkspaceFileValue;
 import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
 import com.google.devtools.build.lib.skyframe.DirtinessCheckerUtils.BasicFilesystemDirtinessChecker;
@@ -138,9 +140,9 @@
             externalFilesHelper));
     skyFunctions.put(FileValue.FILE, new FileFunction(pkgLocator));
     skyFunctions.put(
-        SkyFunctions.FILE_SYMLINK_CYCLE_UNIQUENESS, new FileSymlinkCycleUniquenessFunction());
+        FileSymlinkCycleUniquenessFunction.NAME, new FileSymlinkCycleUniquenessFunction());
     skyFunctions.put(
-        SkyFunctions.FILE_SYMLINK_INFINITE_EXPANSION_UNIQUENESS,
+        FileSymlinkInfiniteExpansionUniquenessFunction.NAME,
         new FileSymlinkInfiniteExpansionUniquenessFunction());
     skyFunctions.put(
         SkyFunctions.PACKAGE, new PackageFunction(null, null, null, null, null, null, null));

diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/LocalRepositoryLookupFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/LocalRepositoryLookupFunctionTest.java
index 3a88497..eb6c31d 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/LocalRepositoryLookupFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/LocalRepositoryLookupFunctionTest.java

@@ -26,6 +26,7 @@
 import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
 import com.google.devtools.build.lib.events.NullEventHandler;
+import com.google.devtools.build.lib.io.FileSymlinkCycleUniquenessFunction;
 import com.google.devtools.build.lib.packages.RuleClassProvider;
 import com.google.devtools.build.lib.packages.WorkspaceFileValue;
 import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
@@ -124,7 +125,7 @@
         SkyFunctions.LOCAL_REPOSITORY_LOOKUP,
         new LocalRepositoryLookupFunction(BazelSkyframeExecutorConstants.EXTERNAL_PACKAGE_HELPER));
     skyFunctions.put(
-        SkyFunctions.FILE_SYMLINK_CYCLE_UNIQUENESS, new FileSymlinkCycleUniquenessFunction());
+        FileSymlinkCycleUniquenessFunction.NAME, new FileSymlinkCycleUniquenessFunction());
 
     differencer = new SequencedRecordingDifferencer();
     evaluator = new InMemoryMemoizingEvaluator(skyFunctions, differencer);

diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/PackageLookupFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/PackageLookupFunctionTest.java
index 73aeb14..31932ec 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/PackageLookupFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/PackageLookupFunctionTest.java

@@ -29,6 +29,7 @@
 import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
 import com.google.devtools.build.lib.events.NullEventHandler;
+import com.google.devtools.build.lib.io.FileSymlinkCycleUniquenessFunction;
 import com.google.devtools.build.lib.packages.BuildFileName;
 import com.google.devtools.build.lib.packages.BuildFileNotFoundException;
 import com.google.devtools.build.lib.packages.RuleClassProvider;
@@ -152,7 +153,7 @@
         SkyFunctions.LOCAL_REPOSITORY_LOOKUP,
         new LocalRepositoryLookupFunction(BazelSkyframeExecutorConstants.EXTERNAL_PACKAGE_HELPER));
     skyFunctions.put(
-        SkyFunctions.FILE_SYMLINK_CYCLE_UNIQUENESS, new FileSymlinkCycleUniquenessFunction());
+        FileSymlinkCycleUniquenessFunction.NAME, new FileSymlinkCycleUniquenessFunction());
 
     ImmutableMap<String, RepositoryFunction> repositoryHandlers =
         ImmutableMap.of(

diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/RecursiveFilesystemTraversalFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/RecursiveFilesystemTraversalFunctionTest.java
index 0d0a332..6778af8 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/RecursiveFilesystemTraversalFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/RecursiveFilesystemTraversalFunctionTest.java

@@ -50,6 +50,8 @@
 import com.google.devtools.build.lib.analysis.util.AnalysisMock;
 import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.events.NullEventHandler;
+import com.google.devtools.build.lib.io.FileSymlinkCycleUniquenessFunction;
+import com.google.devtools.build.lib.io.FileSymlinkInfiniteExpansionUniquenessFunction;
 import com.google.devtools.build.lib.packages.WorkspaceFileValue;
 import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
 import com.google.devtools.build.lib.skyframe.ExternalFilesHelper.ExternalFileAction;
@@ -181,10 +183,10 @@
         SkyFunctions.LOCAL_REPOSITORY_LOOKUP,
         new LocalRepositoryLookupFunction(BazelSkyframeExecutorConstants.EXTERNAL_PACKAGE_HELPER));
     skyFunctions.put(
-        SkyFunctions.FILE_SYMLINK_INFINITE_EXPANSION_UNIQUENESS,
+        FileSymlinkInfiniteExpansionUniquenessFunction.NAME,
         new FileSymlinkInfiniteExpansionUniquenessFunction());
     skyFunctions.put(
-        SkyFunctions.FILE_SYMLINK_CYCLE_UNIQUENESS, new FileSymlinkCycleUniquenessFunction());
+        FileSymlinkCycleUniquenessFunction.NAME, new FileSymlinkCycleUniquenessFunction());
     // We use a non-hermetic key to allow us to invalidate the proper artifacts on rebuilds. We
     // could have the artifact depend on the corresponding FileValue, but that would not cover the
     // case of a generated directory, which we have test coverage for.