Add option to fork default branch only

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

@@ -35,7 +35,6 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
-import java.io.InterruptedIOException;
 import java.io.Reader;
 import java.net.URL;
 import java.util.Arrays;
@@ -1458,23 +1457,11 @@
      * @return Newly forked repository that belong to you.
      * @throws IOException
      *             the io exception
+     * @deprecated Use {@link #createFork()}
      */
+    @Deprecated
     public GHRepository fork() throws IOException {
-        root().createRequest().method("POST").withUrlPath(getApiTailUrl("forks")).send();
-
-        // this API is asynchronous. we need to wait for a bit
-        for (int i = 0; i < 10; i++) {
-            GHRepository r = root().getMyself().getRepository(name);
-            if (r != null) {
-                return r;
-            }
-            try {
-                Thread.sleep(3000);
-            } catch (InterruptedException e) {
-                throw (IOException) new InterruptedIOException().initCause(e);
-            }
-        }
-        throw new IOException(this + " was forked but can't find the new repository");
+        return this.createFork().create();
     }
 
     /**
@@ -1503,27 +1490,11 @@
      * @return Newly forked repository that belong to you.
      * @throws IOException
      *             the io exception
+     * @deprecated Use {@link #createFork()}
      */
+    @Deprecated
     public GHRepository forkTo(GHOrganization org) throws IOException {
-        root().createRequest()
-                .method("POST")
-                .with("organization", org.getLogin())
-                .withUrlPath(getApiTailUrl("forks"))
-                .send();
-
-        // this API is asynchronous. we need to wait for a bit
-        for (int i = 0; i < 10; i++) {
-            GHRepository r = org.getRepository(name);
-            if (r != null) {
-                return r;
-            }
-            try {
-                Thread.sleep(3000);
-            } catch (InterruptedException e) {
-                throw (IOException) new InterruptedIOException().initCause(e);
-            }
-        }
-        throw new IOException(this + " was forked into " + org.getLogin() + " but can't find the new repository");
+        return this.createFork().organization(org).create();
     }
 
     /**
@@ -3435,4 +3406,14 @@
                 .send();
     }
 
+    /**
+     * Create fork gh repository fork builder.
+     * (https://docs.github.com/en/rest/repos/forks?apiVersion=2022-11-28#create-a-fork)
+     *
+     * @return the gh repository fork builder
+     */
+    public GHRepositoryForkBuilder createFork() {
+        return new GHRepositoryForkBuilder(this);
+    }
+
 }

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

@@ -0,0 +1,144 @@
+package org.kohsuke.github;
+
+import java.io.IOException;
+import java.io.InterruptedIOException;
+
+/**
+ * A builder pattern object for creating a fork of a repository.
+ *
+ * @see GHRepository#createFork() GHRepository#createFork()GHRepository#createFork()
+ * @see <a href="https://docs.github.com/en/rest/repos/forks#create-a-fork">Repository fork API</a>
+ */
+public class GHRepositoryForkBuilder {
+    private final GHRepository repo;
+    private final Requester req;
+    private String organization;
+    private String name;
+    private Boolean defaultBranchOnly;
+
+    static int FORK_RETRY_INTERVAL = 3000;
+
+    /**
+     * Instantiates a new Gh repository fork builder.
+     *
+     * @param repo
+     *            the repository
+     */
+    GHRepositoryForkBuilder(GHRepository repo) {
+        this.repo = repo;
+        this.req = repo.root().createRequest();
+    }
+
+    /**
+     * Sets whether to fork only the default branch.
+     *
+     * @param defaultBranchOnly
+     *            the default branch only
+     * @return the gh repository fork builder
+     */
+    public GHRepositoryForkBuilder defaultBranchOnly(boolean defaultBranchOnly) {
+        this.defaultBranchOnly = defaultBranchOnly;
+        return this;
+    }
+
+    /**
+     * Specifies the target organization for the fork.
+     *
+     * @param organization
+     *            the organization
+     * @return the gh repository fork builder
+     */
+    public GHRepositoryForkBuilder organization(GHOrganization organization) {
+        this.organization = organization.getLogin();
+        return this;
+    }
+
+    /**
+     * Sets a custom name for the forked repository.
+     *
+     * @param name
+     *            the desired repository name
+     * @return the builder
+     */
+    public GHRepositoryForkBuilder name(String name) {
+        this.name = name;
+        return this;
+    }
+
+    /**
+     * Creates the fork with the specified parameters.
+     *
+     * @return the gh repository
+     * @throws IOException
+     *             the io exception
+     */
+    public GHRepository create() throws IOException {
+        if (defaultBranchOnly != null) {
+            req.with("default_branch_only", defaultBranchOnly);
+        }
+        if (organization != null) {
+            req.with("organization", organization);
+        }
+        if (name != null) {
+            req.with("name", name);
+        }
+
+        req.method("POST").withUrlPath(repo.getApiTailUrl("forks")).send();
+
+        // this API is asynchronous. we need to wait for a bit
+        for (int i = 0; i < 10; i++) {
+            GHRepository r = lookupForkedRepository();
+            if (r != null) {
+                return r;
+            }
+            sleep(FORK_RETRY_INTERVAL);
+        }
+        throw new IOException(createTimeoutMessage());
+    }
+
+    private GHRepository lookupForkedRepository() throws IOException {
+        String repoName = name != null ? name : repo.getName();
+
+        if (organization != null) {
+            return repo.root().getOrganization(organization).getRepository(repoName);
+        }
+        return repo.root().getMyself().getRepository(repoName);
+    }
+
+    /**
+     * Sleep.
+     *
+     * @param millis
+     *            the millis
+     * @throws IOException
+     *             the io exception
+     */
+    void sleep(int millis) throws IOException {
+        try {
+            Thread.sleep(millis);
+        } catch (InterruptedException e) {
+            throw (IOException) new InterruptedIOException().initCause(e);
+        }
+    }
+
+    /**
+     * Create timeout message string.
+     *
+     * @return the string
+     */
+    String createTimeoutMessage() {
+        StringBuilder message = new StringBuilder(repo.getFullName());
+        message.append(" was forked");
+
+        if (organization != null) {
+            message.append(" into ").append(organization);
+        }
+
+        if (name != null) {
+            message.append(" with name ").append(name);
+        }
+
+        message.append(" but can't find the new repository");
+        return message.toString();
+    }
+}