Automated rollback of commit 7e87730de985b7099b9b683571d58efdaab70890.

*** Reason for rollback ***

Go back to the default constructor - instead of requiring everywhere to know the correct hash function, we'll have the default rely on global state. It will make transition easier, even if it makes the origin of the hash less obvious.

*** Original change description ***

Remove default MD5 in most of Bazel's virtual filesystems.

This forces the ex-default to be explicit in a lot of tests, but I'd rather that than have the risk of implicit md5-use in production code.

To keep this CL smaller, do not remove the default from UnixFS quite yet.

RELNOTES: None.
PiperOrigin-RevId: 206358838

9 files changed, 28 insertions, 20 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/serialization/testutils/FsUtils.java b/src/main/java/com/google/devtools/build/lib/skyframe/serialization/testutils/FsUtils.java
index 1b9e7bbf4f..e244098f32 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/serialization/testutils/FsUtils.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/serialization/testutils/FsUtils.java
@@ -14,7 +14,6 @@
 
 package com.google.devtools.build.lib.skyframe.serialization.testutils;
 
-import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.vfs.Root;
@@ -24,7 +23,7 @@ import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 /** Common FileSystem related items for serialization tests. */
 public class FsUtils {
 
-  public static final FileSystem TEST_FILESYSTEM = new InMemoryFileSystem(DigestHashFunction.MD5);
+  public static final FileSystem TEST_FILESYSTEM = new InMemoryFileSystem();
 
   public static final RootedPath TEST_ROOT =
       RootedPath.toRootedPath(
diff --git a/src/main/java/com/google/devtools/build/lib/unix/UnixFileSystem.java b/src/main/java/com/google/devtools/build/lib/unix/UnixFileSystem.java
index d579ebaf83..5d507c3f95 100644
--- a/src/main/java/com/google/devtools/build/lib/unix/UnixFileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/unix/UnixFileSystem.java
@@ -39,9 +39,6 @@ import java.util.List;
 public class UnixFileSystem extends AbstractFileSystemWithCustomStat {
 
   public UnixFileSystem() {
-    // TODO(b/109764197): remove this parameter-less constructor, so that no one uses MD5 by
-    // default.
-    super(DigestHashFunction.MD5);
   }
 
   public UnixFileSystem(DigestHashFunction hashFunction) {
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/AbstractFileSystem.java b/src/main/java/com/google/devtools/build/lib/vfs/AbstractFileSystem.java
index a5a454c687..096ca500f4 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/AbstractFileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/AbstractFileSystem.java
@@ -30,6 +30,8 @@ public abstract class AbstractFileSystem extends FileSystem {
   protected static final String ERR_PERMISSION_DENIED = " (Permission denied)";
   protected static final Profiler profiler = Profiler.instance();
 
+  public AbstractFileSystem() {}
+
   public AbstractFileSystem(DigestHashFunction digestFunction) {
     super(digestFunction);
   }
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/AbstractFileSystemWithCustomStat.java b/src/main/java/com/google/devtools/build/lib/vfs/AbstractFileSystemWithCustomStat.java
index 2891f12126..2a2b06b50a 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/AbstractFileSystemWithCustomStat.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/AbstractFileSystemWithCustomStat.java
@@ -22,6 +22,8 @@ import java.io.IOException;
  */
 public abstract class AbstractFileSystemWithCustomStat extends AbstractFileSystem {
 
+  public AbstractFileSystemWithCustomStat() {}
+
   public AbstractFileSystemWithCustomStat(DigestHashFunction hashFunction) {
     super(hashFunction);
   }
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/FileSystem.java b/src/main/java/com/google/devtools/build/lib/vfs/FileSystem.java
index 63cf2823f1..8d10e5800b 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/FileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/FileSystem.java
@@ -38,6 +38,10 @@ public abstract class FileSystem {
 
   private final DigestHashFunction digestFunction;
 
+  public FileSystem() {
+    this(DigestHashFunction.MD5);
+  }
+
   public FileSystem(DigestHashFunction digestFunction) {
     this.digestFunction = Preconditions.checkNotNull(digestFunction);
   }
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/JavaIoFileSystem.java b/src/main/java/com/google/devtools/build/lib/vfs/JavaIoFileSystem.java
index 00a320fa57..1fec03f5db 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/JavaIoFileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/JavaIoFileSystem.java
@@ -53,7 +53,7 @@ public class JavaIoFileSystem extends AbstractFileSystemWithCustomStat {
   protected static final String ERR_NOT_A_DIRECTORY = " (Not a directory)";
 
   public JavaIoFileSystem() {
-    this(new JavaClock(), DigestHashFunction.MD5);
+    this(new JavaClock());
   }
 
   public JavaIoFileSystem(DigestHashFunction hashFunction) {
@@ -62,8 +62,7 @@ public class JavaIoFileSystem extends AbstractFileSystemWithCustomStat {
   }
 
   @VisibleForTesting
-  JavaIoFileSystem(Clock clock, DigestHashFunction hashFunction) {
-    super(hashFunction);
+  JavaIoFileSystem(Clock clock) {
     this.clock = clock;
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystem.java b/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystem.java
index f52c786aa7..938f7a7ffb 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystem.java
@@ -36,8 +36,7 @@ import java.io.OutputStream;
  */
 public abstract class ReadonlyFileSystem extends AbstractFileSystem {
 
-  protected ReadonlyFileSystem(DigestHashFunction hashFunction) {
-    super(hashFunction);
+  protected ReadonlyFileSystem() {
   }
 
   protected IOException modificationException() {
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystemWithCustomStat.java b/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystemWithCustomStat.java
index 7ef4a093ab..f9ca4ebb87 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystemWithCustomStat.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystemWithCustomStat.java
@@ -20,9 +20,7 @@ import java.io.OutputStream;
  * Functionally like a {@link ReadonlyFileSystem} and a {@link AbstractFileSystemWithCustomStat}.
  */
 public abstract class ReadonlyFileSystemWithCustomStat extends AbstractFileSystemWithCustomStat {
-
-  protected ReadonlyFileSystemWithCustomStat(DigestHashFunction hashFunction) {
-    super(hashFunction);
+  protected ReadonlyFileSystemWithCustomStat() {
   }
 
   protected IOException modificationException() {
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/inmemoryfs/InMemoryFileSystem.java b/src/main/java/com/google/devtools/build/lib/vfs/inmemoryfs/InMemoryFileSystem.java
index a83d6ab047..504cf21c5b 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/inmemoryfs/InMemoryFileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/inmemoryfs/InMemoryFileSystem.java
@@ -13,7 +13,6 @@
 // limitations under the License.
 package com.google.devtools.build.lib.vfs.inmemoryfs;
 
-import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Lists;
 import com.google.devtools.build.lib.clock.Clock;
@@ -59,23 +58,33 @@ public class InMemoryFileSystem extends FileSystem {
   // Maximum number of traversals before ELOOP is thrown.
   private static final int MAX_TRAVERSALS = 256;
 
-  // TODO(b/109764197): Remove the no-arg constructor from Jadep and then remove it here.
-  @VisibleForTesting
+  /**
+   * Creates a new InMemoryFileSystem with scope checking disabled (all paths are considered to be
+   * within scope) and a default clock.
+   */
   public InMemoryFileSystem() {
-    this(new JavaClock(), DigestHashFunction.MD5);
+    this(new JavaClock());
   }
 
   /**
    * Creates a new InMemoryFileSystem with scope checking disabled (all paths are considered to be
    * within scope) and a default clock.
    *
-   * @param hashFunction
+   * @param hashFunction the function to use for calculating digests.
    */
   public InMemoryFileSystem(DigestHashFunction hashFunction) {
     this(new JavaClock(), hashFunction);
   }
 
   /**
+   * Creates a new InMemoryFileSystem with scope checking disabled (all
+   * paths are considered to be within scope).
+   */
+  public InMemoryFileSystem(Clock clock) {
+    this(clock, (PathFragment) null);
+  }
+
+  /**
    * Creates a new InMemoryFileSystem with scope checking disabled (all paths are considered to be
    * within scope).
    */
@@ -90,8 +99,7 @@ public class InMemoryFileSystem extends FileSystem {
    * Creates a new InMemoryFileSystem with scope checking bound to scopeRoot, i.e. any path that's
    * not below scopeRoot is considered to be out of scope.
    */
-  public InMemoryFileSystem(Clock clock, PathFragment scopeRoot, DigestHashFunction hashFunction) {
-    super(hashFunction);
+  public InMemoryFileSystem(Clock clock, PathFragment scopeRoot) {
     this.scopeRoot = scopeRoot;
     this.clock = clock;
     this.rootInode = newRootInode(clock);