optionally error on files outside of known roots

The goal of this change is to provide a means for disallowing
files outside of declared, known locations in order to better
enforce the hermeticy and in turn reproducability of builds.
Previously when encountering these files (typically via external
symlinks) we would add a dependency on build_id, now we can
optionally fail the build.

--
MOS_MIGRATED_REVID=90015665

1 files changed, 34 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/FileOutsidePackageRootsException.java b/src/main/java/com/google/devtools/build/lib/skyframe/FileOutsidePackageRootsException.java
new file mode 100644
index 0000000000..75f2e91b86
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/FileOutsidePackageRootsException.java
@@ -0,0 +1,34 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// 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;
+
+import com.google.devtools.build.lib.vfs.RootedPath;
+
+import java.io.IOException;
+
+/**
+ * Exception thrown to signal reference to file outside of known/allowed directory structures.
+ * Extends IOException to ensure it is properly handled by skyframe.
+ */
+// TODO(bazel-team): Don't piggyback on existing handling of IOExceptions and instead implement
+// the desired semantics.
+public class FileOutsidePackageRootsException extends IOException {
+
+  /**
+   * @param outsideRoots the {@link RootedPath} that triggered this exception.
+   */
+  public FileOutsidePackageRootsException(RootedPath outsideRoots) {
+    super("Encountered reference to external mutable " + outsideRoots);
+  }
+}