commit 82512519f34fa5b8b031b5feb4396273ec3a13b4
author Janak <janak@janak.org> Mon Jul 13 14:35:14 2015 +0000
committer Florian Weikert <fwe@google.com> Mon Jul 13 15:16:15 2015 +0000
tree 635b16af33bc46f023c912003f28e2ffa31ad986
parent d83e848312f000764a12513887d0cfd10b7d2ea8

Make two Skyframe nodes with the same events and values equal.

We do this by implementing equality for TaggedEvents (and all objects
it transitively includes). Before this change, if a Skyframe node
re-evaluated to the same value as in the previous build, but had
(transitive) events, change pruning would not cut off the evaluation
of its parents. This is not a big issue in practice because most nodes
that would re-evaluate to the same value (like FileValues or
GlobValues) never emit events, and others (like ActionExecutionValues)
have secondary caches that mask this effect.

Also do a drive-by fix where we were using the hash code of a nested
set instead of the shallow hash code (didn't have any bad effects in
practice because we never hash these values).

(Minor formatting clean-ups from https://bazel-review.googlesource.com/1610 )

--
Change-Id: I751a8479627f0456993c5ec8834528aeb593d736
Reviewed-on: https://bazel-review.googlesource.com/1610
MOS_MIGRATED_REVID=98115908

src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java

diff --git a/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java b/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java
index 3bcf0a0..ac629c7 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java
@@ -25,8 +25,10 @@
 import java.io.Serializable;
 import java.nio.CharBuffer;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
+import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -146,6 +148,23 @@
           ? linestart[line + 1]
           : bufferLength);
     }
+
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(Arrays.hashCode(linestart), path, bufferLength);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      if (other == null || !other.getClass().equals(getClass())) {
+        return false;
+      }
+      Regular that = (Regular) other;
+      return this.bufferLength == that.bufferLength
+          && Arrays.equals(this.linestart, that.linestart)
+          && Objects.equals(this.path, that.path);
+    }
   }
 
   /**
@@ -197,7 +216,7 @@
       }
       this.table = hashOrdering.immutableSortedCopy(unorderedTable);
       this.bufferLength = buffer.length;
-      this.defaultPath = defaultPath;
+      this.defaultPath = Preconditions.checkNotNull(defaultPath);
     }
 
     private SingleHashLine getHashLine(int offset) {
@@ -242,5 +261,21 @@
       }
       return Pair.of(0, 0);
     }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(table, defaultPath, bufferLength);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      if (other == null || !other.getClass().equals(getClass())) {
+        return false;
+      }
+      HashLine that = (HashLine) other;
+      return this.bufferLength == that.bufferLength
+          && this.defaultPath.equals(that.defaultPath)
+          && this.table.equals(that.table);
+    }
   }
 }