Make changes backwards compatible

Add '@Deprecation' and '@Preview' annotations to make the changes
backwards compatible and prepare for a transition to the cached behavior
as default.
This explicitly leaves the variant for re-fetching assets under a
different name.

Author: skaldarnar

src/main/java/org/kohsuke/github/GHRelease.java

@@ -251,17 +251,38 @@ public GHAsset uploadAsset(String filename, InputStream stream, String contentTy
     }
 
     /**
-     * Gets assets.
+     * Get the cached assets.
      *
      * @return the assets
+     *
+     * @deprecated This should be the default behavior of {@link #getAssets()} in a future release. This method is
+     *             introduced in addition to enable a transition to using cached asset information while keeping the
+     *             existing logic in place for backwards compatibility.
      */
-    public List<GHAsset> getAssets() {
+    @Deprecated
+    @Preview
+    public List<GHAsset> getCachedAssets() {
         return assets;
     }
 
     /**
      * Re-fetch the assets of this release.
-     * 
+     *
+     * @return the assets
+     * @throws IOException
+     *             the io exception
+     * @deprecated The behavior of this method will change in a future release. It will then provide cached assets as
+     *             provided by {@link #getCachedAssets()}. Use {@link #fetchAssets()} instead to fetch up-to-date
+     *             information of assets.
+     */
+    @Deprecated
+    public List<GHAsset> getAssets() throws IOException {
+        return fetchAssets();
+    }
+
+    /**
+     * Re-fetch the assets of this release.
+     *
      * @return the assets
      * @throws IOException
      *             the io exception

src/test/java/org/kohsuke/github/LifecycleTest.java

@@ -50,13 +50,13 @@ private void updateAsset(GHRelease release, GHAsset asset) throws IOException {
 
     private void deleteAsset(GHRelease release, GHAsset asset) throws IOException {
         asset.delete();
-        assertEquals(0, release.getAssets().size());
+        assertEquals(0, release.getCachedAssets().size());
     }
 
     private GHAsset uploadAsset(GHRelease release) throws IOException {
         GHAsset asset = release.uploadAsset(new File("LICENSE.txt"), "application/text");
         assertNotNull(asset);
-        List<GHAsset> cachedAssets = release.getAssets();
+        List<GHAsset> cachedAssets = release.getCachedAssets();
         assertEquals(0, cachedAssets.size());
         List<GHAsset> assets = release.fetchAssets();
         assertEquals(1, assets.size());