assert + doc

Author: tlrx

x-pack/plugin/searchable-snapshots/src/main/java/org/elasticsearch/xpack/searchablesnapshots/cache/common/CacheFile.java

@@ -127,8 +127,8 @@ protected void closeInternal() {
     private volatile FileChannelReference channelRef;
 
     /**
-     * Indicates if the file has already been created.
-     * This is useful to pass the right options when opening the file.
+     * Indicates if the file should be created when it is open for the first time.
+     * This is required to pass the right options for sparse file support.
      */
     private volatile boolean created;
 
@@ -145,6 +145,7 @@ private CacheFile(CacheKey cacheKey, SparseFileTracker tracker, Path file, Modif
         this.tracker = Objects.requireNonNull(tracker);
         this.file = Objects.requireNonNull(file);
         this.listener = Objects.requireNonNull(listener);
+        assert fileExists == Files.exists(file) : file + " exists? " + fileExists;
         this.created = fileExists;
         assert invariant();
     }

x-pack/plugin/searchable-snapshots/src/test/java/org/elasticsearch/xpack/searchablesnapshots/cache/common/CacheFileTests.java

@@ -58,14 +58,15 @@ public void onCacheFileDelete(CacheFile cacheFile) {}
     private static final CacheKey CACHE_KEY = new CacheKey("_snap_uuid", "_snap_index", new ShardId("_name", "_uuid", 0), "_filename");
 
     public void testGetCacheKey() throws Exception {
+        final Path file = createTempDir().resolve("file.new");
         final CacheKey cacheKey = new CacheKey(
             UUIDs.randomBase64UUID(random()),
             randomAlphaOfLength(5).toLowerCase(Locale.ROOT),
             new ShardId(randomAlphaOfLength(5).toLowerCase(Locale.ROOT), UUIDs.randomBase64UUID(random()), randomInt(5)),
             randomAlphaOfLength(105).toLowerCase(Locale.ROOT)
         );
 
-        final CacheFile cacheFile = new CacheFile(cacheKey, randomLongBetween(1, 100), createTempFile(), NOOP);
+        final CacheFile cacheFile = new CacheFile(cacheKey, randomLongBetween(1, 100), file, NOOP);
         assertThat(cacheFile.getCacheKey(), sameInstance(cacheKey));
     }