Add fork search term DEFAULT, add javadocs

Author: t0m4uk1991

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

@@ -55,6 +55,11 @@ public GHRepositorySearchBuilder forks(String v) {
     /**
      * Searching in forks
      *
+     * By default, forks are not shown in search results. Forks are only indexed for code search when they have more
+     * stars than the parent repository. You will not be able to search the code in a fork that has less stars than its
+     * parent. To show forks with more stars than the parent repository in code search results, add
+     * Fork.ALL_INCLUDING_FORKS or Fork.FORKS_ONLY.
+     *
      * @param fork
      *            search mode for forks
      *
@@ -66,6 +71,11 @@ public GHRepositorySearchBuilder forks(String v) {
      *
      */
     public GHRepositorySearchBuilder fork(Fork fork) {
+        if (fork == Fork.DEFAULT) {
+            this.terms.removeIf(term -> term.contains("fork:"));
+            return this;
+        }
+
         return q("fork:" + fork);
     }
 
@@ -200,9 +210,14 @@ public enum Sort {
 
     /**
      * The enum Fork.
+     *
+     * By default, forks are not shown in search results. Forks are only indexed for code search when they have more
+     * stars than the parent repository. You will not be able to search the code in a fork that has less stars than its
+     * parent. To show forks with more stars than the parent repository in code search results, add
+     * Fork.ALL_INCLUDING_FORKS or Fork.FORKS_ONLY.
      */
     public enum Fork {
-        ALL_INCLUDING_FORKS("true"), FORKS_ONLY("only");
+        ALL_INCLUDING_FORKS("true"), FORKS_ONLY("only"), DEFAULT("ignore");
 
         private String filterMode;
         Fork(String mode) {

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

@@ -459,6 +459,21 @@ public void ghRepositorySearchBuilderIgnoresUnknownVisibility() {
         assertThat(ghRepositorySearchBuilder.terms.stream().filter(item -> item.contains("is:")).count(), is(1L));
     }
 
+    @Test
+    public void ghRepositorySearchBuilderForkDefaultResetForksSearchTerms() {
+        GHRepositorySearchBuilder ghRepositorySearchBuilder = new GHRepositorySearchBuilder(gitHub);
+        ghRepositorySearchBuilder = ghRepositorySearchBuilder.fork(GHRepositorySearchBuilder.Fork.ALL_INCLUDING_FORKS);
+        assertThat(ghRepositorySearchBuilder.terms.stream().filter(item -> item.contains("fork:true")).count(), is(1L));
+        assertThat(ghRepositorySearchBuilder.terms.stream().filter(item -> item.contains("fork:")).count(), is(1L));
+
+        ghRepositorySearchBuilder = ghRepositorySearchBuilder.fork(GHRepositorySearchBuilder.Fork.FORKS_ONLY);
+        assertThat(ghRepositorySearchBuilder.terms.stream().filter(item -> item.contains("fork:only")).count(), is(1L));
+        assertThat(ghRepositorySearchBuilder.terms.stream().filter(item -> item.contains("fork:")).count(), is(2L));
+
+        ghRepositorySearchBuilder = ghRepositorySearchBuilder.fork(GHRepositorySearchBuilder.Fork.DEFAULT);
+        assertThat(ghRepositorySearchBuilder.terms.stream().filter(item -> item.contains("fork:")).count(), is(0L));
+    }
+
     @Test
     public void listCommitCommentsSomeComments() throws IOException {
         List<GHCommitComment> commitComments = getRepository()