Fix output base under /tmp.

src/main/java/com/google/devtools/build/lib/actions/FileArtifactValue.java

@@ -171,9 +171,12 @@ protected boolean couldBeModifiedByMetadata(FileArtifactValue lastKnown) {
    *
    * <p>If present, this artifact is a copy of another artifact. It is still tracked as a
    * non-symlink by Bazel, but materialized in the local filesystem as a symlink to the original
-   * artifact, whose contents live at this location. This is used by {@link
+   * artifact, whose contents live at this location.
+   *
+   * <p>This is used by {@link
    * com.google.devtools.build.lib.remote.AbstractActionInputPrefetcher} to implement zero-cost
-   * copies of remotely stored artifacts.
+   * copies of remotely stored artifacts and to tack which real files (artifact or otherwise)
+   * resolved symlink artifacts point to.
    */
   public Optional<PathFragment> getMaterializationExecPath() {
     return Optional.empty();
@@ -214,6 +217,12 @@ public static FileArtifactValue createForSourceArtifact(
         xattrProvider);
   }
 
+  public static FileArtifactValue createForResolvedSymlink(
+      PathFragment realPath, FileArtifactValue metadata, @Nullable byte[] digest) {
+    return new ResolvedSymlinkFileArtifactValue(
+        realPath, digest, metadata.getContentsProxy(), metadata.getSize());
+  }
+
   public static FileArtifactValue createFromInjectedDigest(
       FileArtifactValue metadata, @Nullable byte[] digest) {
     return createForNormalFile(digest, metadata.getContentsProxy(), metadata.getSize());
@@ -439,7 +448,22 @@ public String toString() {
     }
   }
 
-  private static final class RegularFileArtifactValue extends FileArtifactValue {
+  private static final class ResolvedSymlinkFileArtifactValue extends RegularFileArtifactValue {
+    private final PathFragment realPath;
+
+    private ResolvedSymlinkFileArtifactValue(PathFragment realPath, @Nullable byte[] digest,
+        @Nullable FileContentsProxy proxy, long size) {
+      super(digest, proxy, size);
+      this.realPath = realPath;
+    }
+
+    @Override
+    public Optional<PathFragment> getMaterializationExecPath() {
+      return Optional.of(realPath);
+    }
+  }
+
+  private static class RegularFileArtifactValue extends FileArtifactValue {
     private final byte[] digest;
     @Nullable private final FileContentsProxy proxy;
     private final long size;

src/main/java/com/google/devtools/build/lib/sandbox/BUILD

@@ -17,6 +17,7 @@ java_library(
     deps = [
         "//src/main/java/com/google/devtools/build/lib/actions",
         "//src/main/java/com/google/devtools/build/lib/actions:artifacts",
+        "//src/main/java/com/google/devtools/build/lib/actions:file_metadata",
         "//src/main/java/com/google/devtools/build/lib/analysis:test/test_configuration",
         "//src/main/java/com/google/devtools/build/lib/cmdline",
         "//src/main/java/com/google/devtools/build/lib/vfs",

src/main/java/com/google/devtools/build/lib/sandbox/DarwinSandboxedSpawnRunner.java

@@ -228,6 +228,7 @@ protected SandboxedSpawn prepareSpawn(Spawn spawn, SpawnExecutionContext context
     SandboxInputs inputs =
         helpers.processInputFiles(
             context.getInputMapping(PathFragment.EMPTY_FRAGMENT, /* willAccessRepeatedly= */ true),
+            context.getInputMetadataProvider(),
             execRoot,
             execRoot,
             packageRoots,

src/main/java/com/google/devtools/build/lib/sandbox/DockerSandboxedSpawnRunner.java

@@ -226,6 +226,7 @@ protected SandboxedSpawn prepareSpawn(Spawn spawn, SpawnExecutionContext context
     SandboxInputs inputs =
         helpers.processInputFiles(
             context.getInputMapping(PathFragment.EMPTY_FRAGMENT, /* willAccessRepeatedly= */ true),
+            context.getInputMetadataProvider(),
             execRoot,
             execRoot,
             packageRoots,

src/main/java/com/google/devtools/build/lib/sandbox/LinuxSandboxedSpawnRunner.java

@@ -281,6 +281,7 @@ protected SandboxedSpawn prepareSpawn(Spawn spawn, SpawnExecutionContext context
     SandboxInputs inputs =
         helpers.processInputFiles(
             context.getInputMapping(PathFragment.EMPTY_FRAGMENT, /* willAccessRepeatedly= */ true),
+            context.getInputMetadataProvider(),
             execRoot,
             withinSandboxExecRoot,
             packageRoots,

src/main/java/com/google/devtools/build/lib/sandbox/ProcessWrapperSandboxedSpawnRunner.java

@@ -100,6 +100,7 @@ protected SandboxedSpawn prepareSpawn(Spawn spawn, SpawnExecutionContext context
     SandboxInputs inputs =
         helpers.processInputFiles(
             context.getInputMapping(PathFragment.EMPTY_FRAGMENT, /* willAccessRepeatedly= */ true),
+            context.getInputMetadataProvider(),
             execRoot,
             execRoot,
             packageRoots,

src/main/java/com/google/devtools/build/lib/sandbox/SandboxHelpers.java

@@ -20,6 +20,7 @@
 import static com.google.devtools.build.lib.vfs.Dirent.Type.SYMLINK;
 
 import com.google.auto.value.AutoValue;
+import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -29,6 +30,8 @@
 import com.google.common.flogger.GoogleLogger;
 import com.google.devtools.build.lib.actions.ActionInput;
 import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.actions.FileArtifactValue;
+import com.google.devtools.build.lib.actions.InputMetadataProvider;
 import com.google.devtools.build.lib.actions.Spawn;
 import com.google.devtools.build.lib.actions.UserExecException;
 import com.google.devtools.build.lib.actions.cache.VirtualActionInput;
@@ -444,6 +447,29 @@ private static RootedPath processFilesetSymlink(
             symlink.getPathString()));
   }
 
+  private static RootedPath processResolvedSymlink(
+      Root absoluteRoot,
+      PathFragment execRootRelativeSymlinkTarget,
+      Root execRootWithinSandbox,
+      PathFragment execRootFragment,
+      ImmutableList<Root> packageRoots,
+      Function<Root, Root> sourceRooWithinSandbox) {
+    PathFragment symlinkTarget = execRootFragment.getRelative(execRootRelativeSymlinkTarget);
+    for (Root packageRoot : packageRoots) {
+      if (packageRoot.contains(symlinkTarget)) {
+        return RootedPath.toRootedPath(
+            sourceRooWithinSandbox.apply(packageRoot),
+            packageRoot.relativize(symlinkTarget));
+      }
+    }
+
+    if (symlinkTarget.startsWith(execRootFragment)) {
+      return RootedPath.toRootedPath(execRootWithinSandbox, symlinkTarget.relativeTo(execRootFragment));
+    }
+
+    return RootedPath.toRootedPath(absoluteRoot, symlinkTarget);
+  }
+
   /**
    * Returns the inputs of a Spawn as a map of PathFragments relative to an execRoot to paths in the
    * host filesystem where the input files can be found.
@@ -458,6 +484,7 @@ private static RootedPath processFilesetSymlink(
    */
   public SandboxInputs processInputFiles(
       Map<PathFragment, ActionInput> inputMap,
+      InputMetadataProvider inputMetadataProvider,
       Path execRootPath,
       Path withinSandboxExecRootPath,
       ImmutableList<Root> packageRoots,
@@ -468,12 +495,24 @@ public SandboxInputs processInputFiles(
         withinSandboxExecRootPath.equals(execRootPath)
             ? withinSandboxExecRoot
             : Root.fromPath(execRootPath);
+    Root absoluteRoot = Root.absoluteRoot(execRootPath.getFileSystem());
 
     Map<PathFragment, RootedPath> inputFiles = new TreeMap<>();
     Map<PathFragment, PathFragment> inputSymlinks = new TreeMap<>();
     Map<VirtualActionInput, byte[]> virtualInputs = new HashMap<>();
     Map<Root, Root> sourceRootToSandboxSourceRoot = new TreeMap<>();
 
+    Function<Root, Root> sourceRootWithinSandbox = r -> {
+      if (!sourceRootToSandboxSourceRoot.containsKey(r)) {
+        int next = sourceRootToSandboxSourceRoot.size();
+        sourceRootToSandboxSourceRoot.put(
+            r,
+            Root.fromPath(sandboxSourceRoots.getRelative(Integer.toString(next))));
+      }
+
+      return sourceRootToSandboxSourceRoot.get(r);
+    };
+
     for (Map.Entry<PathFragment, ActionInput> e : inputMap.entrySet()) {
       if (Thread.interrupted()) {
         throw new InterruptedException();
@@ -503,23 +542,47 @@ public SandboxInputs processInputFiles(
 
         if (actionInput instanceof EmptyActionInput) {
           inputPath = null;
+        } else if (actionInput instanceof VirtualActionInput) {
+          inputPath = RootedPath.toRootedPath(withinSandboxExecRoot, actionInput.getExecPath());
         } else if (actionInput instanceof Artifact) {
           Artifact inputArtifact = (Artifact) actionInput;
-          if (inputArtifact.isSourceArtifact() && sandboxSourceRoots != null) {
-            Root sourceRoot = inputArtifact.getRoot().getRoot();
-            if (!sourceRootToSandboxSourceRoot.containsKey(sourceRoot)) {
-              int next = sourceRootToSandboxSourceRoot.size();
-              sourceRootToSandboxSourceRoot.put(
-                  sourceRoot,
-                  Root.fromPath(sandboxSourceRoots.getRelative(Integer.toString(next))));
-            }
-
-            inputPath =
-                RootedPath.toRootedPath(
-                    sourceRootToSandboxSourceRoot.get(sourceRoot),
-                    inputArtifact.getRootRelativePath());
-          } else {
+          if (sandboxSourceRoots == null) {
             inputPath = RootedPath.toRootedPath(withinSandboxExecRoot, inputArtifact.getExecPath());
+          } else {
+            if (inputArtifact.isSourceArtifact()) {
+              Root sourceRoot = inputArtifact.getRoot().getRoot();
+              inputPath =
+                  RootedPath.toRootedPath(
+                      sourceRootWithinSandbox.apply(sourceRoot),
+                      inputArtifact.getRootRelativePath());
+            } else {
+              PathFragment materializationExecPath = null;
+              if (inputArtifact.isChildOfDeclaredDirectory()) {
+                FileArtifactValue parentMetadata = inputMetadataProvider.getInputMetadata(inputArtifact.getParent());
+                if (parentMetadata.getMaterializationExecPath().isPresent()) {
+                  materializationExecPath =
+                      parentMetadata.getMaterializationExecPath().get()
+                          .getRelative(inputArtifact.getParentRelativePath());
+                }
+              } else {
+                FileArtifactValue metadata = inputMetadataProvider.getInputMetadata(actionInput);
+                if (metadata.getMaterializationExecPath().isPresent()) {
+                  materializationExecPath = metadata.getMaterializationExecPath().get();
+                }
+              }
+
+              if (materializationExecPath != null) {
+                inputPath = processResolvedSymlink(
+                    absoluteRoot,
+                    materializationExecPath,
+                    withinSandboxExecRoot,
+                    execRootPath.asFragment(),
+                    packageRoots,
+                    sourceRootWithinSandbox);
+              } else {
+                inputPath = RootedPath.toRootedPath(withinSandboxExecRoot, inputArtifact.getExecPath());
+              }
+            }
           }
         } else {
           PathFragment execPath = actionInput.getExecPath();

src/main/java/com/google/devtools/build/lib/sandbox/WindowsSandboxedSpawnRunner.java

@@ -76,6 +76,7 @@ protected SandboxedSpawn prepareSpawn(Spawn spawn, SpawnExecutionContext context
     SandboxInputs readablePaths =
         helpers.processInputFiles(
             context.getInputMapping(PathFragment.EMPTY_FRAGMENT, /* willAccessRepeatedly= */ true),
+            context.getInputMetadataProvider(),
             execRoot,
             execRoot,
             packageRoots,

src/main/java/com/google/devtools/build/lib/skyframe/ActionOutputMetadataStore.java

@@ -332,12 +332,19 @@ private TreeArtifactValue constructTreeArtifactValueFromFilesystem(SpecialArtifa
     }
 
     // Same rationale as for constructFileArtifactValue.
-    if (anyRemote.get() && treeDir.isSymbolicLink() && stat instanceof FileStatusWithMetadata) {
-      FileArtifactValue metadata = ((FileStatusWithMetadata) stat).getMetadata();
-      tree.setMaterializationExecPath(
-          metadata
-              .getMaterializationExecPath()
-              .orElse(treeDir.resolveSymbolicLinks().asFragment().relativeTo(execRoot)));
+    if (treeDir.isSymbolicLink()) {
+      PathFragment materializationExecPath = null;
+      if (stat instanceof FileStatusWithMetadata) {
+        materializationExecPath = ((FileStatusWithMetadata) stat).getMetadata()
+            .getMaterializationExecPath()
+            .orElse(null);
+      }
+
+      if (materializationExecPath == null) {
+        materializationExecPath = treeDir.resolveSymbolicLinks().asFragment().relativeTo(execRoot);
+      }
+
+      tree.setMaterializationExecPath(materializationExecPath);
     }
 
     return tree.build();
@@ -536,6 +543,16 @@ private FileArtifactValue constructFileArtifactValue(
         // possible to hit the digest cache - we probably already computed the digest for the
         // target during previous action execution.
         path = statAndValue.realPath();
+        injectedDigest = DigestUtils.manuallyComputeDigest(path, value.getSize());
+
+        PathFragment execRootRelativeRealPath;
+        if (path.asFragment().startsWith(execRoot)) {
+          execRootRelativeRealPath = path.asFragment().relativeTo(execRoot);
+        } else {
+          execRootRelativeRealPath = path.asFragment();
+        }
+
+        return FileArtifactValue.createForResolvedSymlink(execRootRelativeRealPath, value, injectedDigest);
       }
 
       injectedDigest = DigestUtils.manuallyComputeDigest(path, value.getSize());

src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnRunner.java

@@ -189,6 +189,7 @@ public SpawnResult exec(Spawn spawn, SpawnExecutionContext context)
             helpers.processInputFiles(
                 context.getInputMapping(
                     PathFragment.EMPTY_FRAGMENT, /* willAccessRepeatedly= */ true),
+                context.getInputMetadataProvider(),
                 execRoot,
                 execRoot,
                 packageRoots,

src/test/java/com/google/devtools/build/lib/sandbox/BUILD

@@ -59,12 +59,14 @@ java_test(
     deps = [
         "//src/main/java/com/google/devtools/build/lib/actions",
         "//src/main/java/com/google/devtools/build/lib/actions:artifacts",
+        "//src/main/java/com/google/devtools/build/lib/actions:file_metadata",
         "//src/main/java/com/google/devtools/build/lib/exec:bin_tools",
         "//src/main/java/com/google/devtools/build/lib/exec:tree_deleter",
         "//src/main/java/com/google/devtools/build/lib/sandbox:sandbox_helpers",
         "//src/main/java/com/google/devtools/build/lib/sandbox:sandbox_options",
         "//src/main/java/com/google/devtools/build/lib/sandbox:sandboxed_spawns",
         "//src/main/java/com/google/devtools/build/lib/sandbox:tree_deleter",
+        "//src/main/java/com/google/devtools/build/lib/skyframe:tree_artifact_value",
         "//src/main/java/com/google/devtools/build/lib/vfs",
         "//src/main/java/com/google/devtools/build/lib/vfs:pathfragment",
         "//src/main/java/com/google/devtools/build/lib/vfs/inmemoryfs",