Rollback of commit e0d7a540e3c615c628f63fcaaaba0c47fca2cb25.

*** Reason for rollback ***

Suspected root cause for Windows bootstrap on Bazel CI breakage:

java.lang.NullPointerException
	at com.google.devtools.build.lib.vfs.Path$1.run(Path.java:123)

http://ci.bazel.io/view/Bazel%20bootstrap%20and%20maintenance/job/Bazel/922/JAVA_VERSION=1.8,PLATFORM_NAME=windows-x86_64/console

*** Original change description ***

VFS: implement a Windows-specific Path subclass

The new subclass WindowsFileSystem.WindowsPath is
aware of Windows drives.

This change:
- introduces a new factory for Path objects so
  FileSystems can return a custom implementation
  that instantiates filesystem-specific Paths
- implements the WindowsPath subclass of Path that
  is aware of Windows drives
- introduces the bazel.windows_unix_root JVM
  argument that defines the MSYS root, which
  defines the absolute Windows path that is the...

***

--
MOS_MIGRATED_REVID=136583352

5 files changed, 32 insertions, 189 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/BUILD b/src/test/java/com/google/devtools/build/lib/BUILD
index 0556e41c5a..942d9a337d 100644
--- a/src/test/java/com/google/devtools/build/lib/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/BUILD
@@ -169,10 +169,7 @@ java_test(
 java_test(
     name = "windows_test",
     srcs = CROSS_PLATFORM_WINDOWS_TESTS,
-    jvm_flags = [
-        "-Dblaze.os=Windows",
-        "-Dbazel.windows_unix_root=C:/fake/msys",
-    ],
+    jvm_flags = ["-Dblaze.os=Windows"],
     test_class = "com.google.devtools.build.lib.AllTests",
     deps = [
         ":foundations_testutil",
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentTest.java b/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentTest.java
index c4ac7c1b32..2a41b10ee6 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentTest.java
@@ -26,13 +26,15 @@ import com.google.common.collect.Lists;
 import com.google.common.testing.EqualsTester;
 import com.google.devtools.build.lib.testutil.TestUtils;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
-import java.io.File;
-import java.util.Collections;
-import java.util.List;
+
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
+import java.io.File;
+import java.util.Collections;
+import java.util.List;
+
 /**
  * This class tests the functionality of the PathFragment.
  */
@@ -67,16 +69,15 @@ public class PathFragmentTest {
     InMemoryFileSystem filesystem = new InMemoryFileSystem();
 
     new EqualsTester()
-        .addEqualityGroup(
-            new PathFragment("../relative/path"),
-            new PathFragment("..").getRelative("relative").getRelative("path"),
-            new PathFragment('\0', false, new String[] {"..", "relative", "path"}),
-            new PathFragment(new File("../relative/path")))
+        .addEqualityGroup(new PathFragment("../relative/path"),
+                          new PathFragment("../relative/path"),
+                          new PathFragment(new File("../relative/path")))
         .addEqualityGroup(new PathFragment("something/else"))
         .addEqualityGroup(new PathFragment("/something/else"))
-        .addEqualityGroup(new PathFragment("/"), new PathFragment("//////"))
-        .addEqualityGroup(new PathFragment(""), PathFragment.EMPTY_FRAGMENT)
-        .addEqualityGroup(filesystem.getRootDirectory()) // A Path object.
+        .addEqualityGroup(new PathFragment("/"),
+                          new PathFragment("//////"))
+        .addEqualityGroup(new PathFragment(""))
+        .addEqualityGroup(filesystem.getRootDirectory())  // A Path object.
         .testEquals();
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentWindowsTest.java b/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentWindowsTest.java
index df2c770d98..48a63e34dc 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentWindowsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentWindowsTest.java
@@ -14,24 +14,23 @@
 package com.google.devtools.build.lib.vfs;
 
 import static com.google.common.truth.Truth.assertThat;
-import static com.google.common.truth.Truth.assertWithMessage;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
-import java.io.File;
-import org.junit.Assert;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
+import java.io.File;
+
 /**
  * This class tests the functionality of the PathFragment.
  */
 @RunWith(JUnit4.class)
 public class PathFragmentWindowsTest {
-
+  
   @Test
   public void testWindowsSeparator() {
     assertEquals("bar/baz", new PathFragment("bar\\baz").toString());
@@ -53,26 +52,6 @@ public class PathFragmentWindowsTest {
   }
 
   @Test
-  public void testAbsolutePathsWithDrive() {
-    PathFragment p1 = new PathFragment("/c");
-    assertThat(p1.isAbsolute()).isTrue();
-    assertThat(p1.getDriveLetter()).isEqualTo('C');
-
-    PathFragment p2 = new PathFragment("/c/");
-    assertThat(p2.isAbsolute()).isTrue();
-    assertThat(p2.getDriveLetter()).isEqualTo('C');
-
-    assertThat(p1).isEqualTo(p2);
-
-    try {
-      new PathFragment("/c:");
-      Assert.fail("expected failure");
-    } catch (IllegalArgumentException e) {
-      assertThat(e.getMessage()).contains("Illegal path string \"/c:\"");
-    }
-  }
-
-  @Test
   public void testIsAbsoluteWindowsBackslash() {
     assertTrue(new PathFragment(new File("C:\\blah")).isAbsolute());
     assertTrue(new PathFragment(new File("C:\\")).isAbsolute());
@@ -104,75 +83,10 @@ public class PathFragmentWindowsTest {
     assertEquals("C:/c/d", new PathFragment("a/b").getRelative("C:/c/d").getPathString());
   }
 
-  private void assertGetRelative(String path, String relative, PathFragment expected)
-      throws Exception {
-    PathFragment actual = new PathFragment(path).getRelative(relative);
-    assertThat(actual.getPathString()).isEqualTo(expected.getPathString());
-    assertThat(actual).isEqualTo(expected);
-    assertThat(actual.getDriveLetter()).isEqualTo(expected.getDriveLetter());
-    assertThat(actual.hashCode()).isEqualTo(expected.hashCode());
-  }
-
-  private void assertRelativeTo(String path, String relativeTo, String... expectedPathSegments)
-      throws Exception {
-    PathFragment expected = new PathFragment('\0', false, expectedPathSegments);
-    PathFragment actual = new PathFragment(path).relativeTo(relativeTo);
-    assertThat(actual.getPathString()).isEqualTo(expected.getPathString());
-    assertThat(actual).isEqualTo(expected);
-    assertThat(actual.getDriveLetter()).isEqualTo(expected.getDriveLetter());
-    assertThat(actual.hashCode()).isEqualTo(expected.hashCode());
-  }
-
-  private void assertCantComputeRelativeTo(String path, String relativeTo) throws Exception {
-    try {
-      new PathFragment(path).relativeTo(relativeTo);
-      Assert.fail("expected failure");
-    } catch (Exception e) {
-      assertThat(e.getMessage()).contains("is not beneath");
-    }
-  }
-
-  private static PathFragment makePath(char drive, boolean absolute, String... segments) {
-    return new PathFragment(drive, absolute, segments);
-  }
-
   @Test
-  public void testGetRelativeMixed() throws Exception {
-    assertGetRelative("a", "b", makePath('\0', false, "a", "b"));
-    assertGetRelative("a", "/b", makePath('B', true));
-    assertGetRelative("a", "E:b", makePath('\0', false, "a", "b"));
-    assertGetRelative("a", "E:/b", makePath('E', true, "b"));
-
-    assertGetRelative("/a", "b", makePath('A', true, "b"));
-    assertGetRelative("/a", "/b", makePath('B', true));
-    assertGetRelative("/a", "E:b", makePath('A', true, "b"));
-    assertGetRelative("/a", "E:/b", makePath('E', true, "b"));
-
-    assertGetRelative("D:a", "b", makePath('D', false, "a", "b"));
-    assertGetRelative("D:a", "/b", makePath('B', true));
-    assertGetRelative("D:a", "E:b", makePath('D', false, "a", "b"));
-    assertGetRelative("D:a", "E:/b", makePath('E', true, "b"));
-
-    assertGetRelative("D:/a", "b", makePath('D', true, "a", "b"));
-    assertGetRelative("D:/a", "/b", makePath('B', true));
-    assertGetRelative("D:/a", "E:b", makePath('D', true, "a", "b"));
-    assertGetRelative("D:/a", "E:/b", makePath('E', true, "b"));
-  }
-
-  @Test
-  public void testRelativeTo() throws Exception {
-    assertRelativeTo("", "");
-    assertCantComputeRelativeTo("", "a");
-
-    assertRelativeTo("a", "", "a");
-    assertRelativeTo("a", "a");
-    assertCantComputeRelativeTo("a", "b");
-    assertRelativeTo("a/b", "a", "b");
-
-    assertRelativeTo("C:", "");
-    assertRelativeTo("C:", "C:");
-    assertCantComputeRelativeTo("C:/", "");
-    assertRelativeTo("C:/", "C:/");
+  public void testGetRelativeMixed() {
+    assertEquals("/b", new PathFragment("C:/a").getRelative("/b").getPathString());
+    assertEquals("C:/b", new PathFragment("/a").getRelative("C:/b").getPathString());
   }
 
   @Test
@@ -183,12 +97,8 @@ public class PathFragmentWindowsTest {
 
   // Tests after here test the canonicalization
   private void assertRegular(String expected, String actual) {
-    PathFragment exp = new PathFragment(expected);
-    PathFragment act = new PathFragment(actual);
-    assertThat(exp.getPathString()).isEqualTo(expected);
-    assertThat(act.getPathString()).isEqualTo(expected);
-    assertThat(act).isEqualTo(exp);
-    assertThat(act.hashCode()).isEqualTo(exp.hashCode());
+    assertEquals(expected, new PathFragment(actual).getPathString()); // compare string forms
+    assertEquals(new PathFragment(expected), new PathFragment(actual)); // compare fragment forms
   }
 
   @Test
@@ -196,38 +106,9 @@ public class PathFragmentWindowsTest {
     assertRegular("C:/", "C:/");
   }
 
-  private void assertAllEqual(PathFragment... ps) {
-    assertThat(ps.length).isGreaterThan(1);
-    for (int i = 1; i < ps.length; i++) {
-      String msg = "comparing items 0 and " + i;
-      assertWithMessage(msg + " for getPathString")
-          .that(ps[i].getPathString())
-          .isEqualTo(ps[0].getPathString());
-      assertWithMessage(msg + " for equals").that(ps[0]).isEqualTo(ps[i]);
-      assertWithMessage(msg + " for hashCode").that(ps[0].hashCode()).isEqualTo(ps[i].hashCode());
-    }
-  }
-
   @Test
   public void testEmptyRelativePathToEmptyPathWindows() {
-    // Surprising but correct behavior: a PathFragment made of just a drive identifier (and not the
-    // absolute path "C:/") is equal not only to the empty fragment, but (therefore) also to other
-    // drive identifiers.
-    // This makes sense if you consider that these are still empty paths, the drive letter adds no
-    // information to the path itself.
-    assertAllEqual(
-        PathFragment.EMPTY_FRAGMENT,
-        new PathFragment("C:"),
-        new PathFragment("D:"),
-        new PathFragment('\0', false, new String[0]),
-        new PathFragment('C', false, new String[0]),
-        new PathFragment('D', false, new String[0]));
-    assertAllEqual(new PathFragment("C:/"), new PathFragment("/c"), new PathFragment("/c/"));
-    assertAllEqual(new PathFragment("C:/foo"), new PathFragment("/c/foo"));
-
-    assertThat(new PathFragment("C:/")).isNotEqualTo(new PathFragment("C:"));
-    assertThat(new PathFragment("C:/").getPathString())
-        .isNotEqualTo(new PathFragment("C:").getPathString());
+    assertRegular("C:", "C:");
   }
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/PathWindowsTest.java b/src/test/java/com/google/devtools/build/lib/vfs/PathWindowsTest.java
index 864a483536..cb8b23b000 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/PathWindowsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/PathWindowsTest.java
@@ -18,10 +18,8 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertSame;
 
 import com.google.devtools.build.lib.util.BlazeClock;
-import com.google.devtools.build.lib.vfs.Path.PathFactory;
-import com.google.devtools.build.lib.vfs.WindowsFileSystem.WindowsPathFactory;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
-import org.junit.Assert;
+
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -37,16 +35,8 @@ public class PathWindowsTest {
 
   @Before
   public final void initializeFileSystem() throws Exception  {
-    filesystem =
-        new InMemoryFileSystem(BlazeClock.instance()) {
-          @Override
-          protected PathFactory getPathFactory() {
-            return WindowsPathFactory.INSTANCE;
-          }
-        };
-    root = filesystem.getRootDirectory().getRelative("C:/");
-    root.createDirectory();
-
+    filesystem = new InMemoryFileSystem(BlazeClock.instance());
+    root = filesystem.getRootDirectory();
     Path first = root.getChild("first");
     first.createDirectory();
   }
@@ -108,38 +98,10 @@ public class PathWindowsTest {
   }
 
   @Test
-  public void testAbsoluteUnixPathIsRelativeToWindowsUnixRoot() {
-    Path actual = root.getRelative("/foo/bar");
-    Path expected = root.getRelative("C:/fake/msys/foo/bar");
-    assertThat(actual.getPathString()).isEqualTo(expected.getPathString());
-    assertThat(actual).isEqualTo(expected);
-  }
-
-  @Test
-  public void testAbsoluteUnixPathReferringToDriveIsRecognized() {
-    Path actual = root.getRelative("/c/foo");
-    Path expected = root.getRelative("C:/foo");
-    assertThat(actual.getPathString()).isEqualTo(expected.getPathString());
-    assertThat(actual).isEqualTo(expected);
-
-    // "unexpected" is not a valid MSYS path, we should not be able to create it.
-    try {
-      root.getRelative("/c:");
-      Assert.fail("expected failure");
-    } catch (IllegalArgumentException e) {
-      assertThat(e.getMessage()).contains("Illegal path string \"/c:\"");
-    }
-  }
-
-  @Test
   public void testStartsWithWorksOnWindows() {
     assertStartsWithReturnsOnWindows(true, "C:/first/x", "C:/first/x/y");
     assertStartsWithReturnsOnWindows(true, "c:/first/x", "C:/FIRST/X/Y");
     assertStartsWithReturnsOnWindows(true, "C:/FIRST/X", "c:/first/x/y");
-    assertStartsWithReturnsOnWindows(true, "/", "C:/");
-    assertStartsWithReturnsOnWindows(false, "C:/", "/");
-    assertStartsWithReturnsOnWindows(false, "C:/", "D:/");
-    assertStartsWithReturnsOnWindows(false, "C:/", "D:/foo");
   }
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/UnixPathTest.java b/src/test/java/com/google/devtools/build/lib/vfs/UnixPathTest.java
index e2317bf0f1..2be505548a 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/UnixPathTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/UnixPathTest.java
@@ -24,6 +24,12 @@ import com.google.common.collect.Lists;
 import com.google.common.testing.EqualsTester;
 import com.google.devtools.build.lib.testutil.TestUtils;
 import com.google.devtools.build.lib.vfs.util.FileSystems;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
 import java.io.File;
 import java.io.FileWriter;
 import java.io.IOException;
@@ -33,10 +39,6 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
 
 /**
  * Tests for {@link Path}.
@@ -267,7 +269,7 @@ public class UnixPathTest {
 
   @Test
   public void testDerivedSegmentEquality() {
-    Path absoluteSegment = unixFs.getRootDirectory();
+    Path absoluteSegment = new Path(null);
 
     Path derivedNode = absoluteSegment.getChild("derivedSegment");
     Path otherDerivedNode = absoluteSegment.getChild("derivedSegment");