Fix cliUrl to auto-correct useStdio for backend service scenarios (#97)

When cliUrl is set (connecting to an external CLI server), useStdio is now
automatically set to false since TCP is inherently required. Previously,
users had to explicitly call setUseStdio(false) alongside setCliUrl(),
which contradicted the setup.md documentation.

Also simplified CliServerManager.connectToServer to be parameter-driven
rather than flag-driven, and updated tests accordingly.

Author: brunoborges

src/main/java/com/github/copilot/sdk/CliServerManager.java

@@ -127,17 +127,15 @@ ProcessInfo startCliServer() throws IOException, InterruptedException {
      *             if connection fails
      */
     JsonRpcClient connectToServer(Process process, String tcpHost, Integer tcpPort) throws IOException {
-        if (options.isUseStdio()) {
-            if (process == null) {
-                throw new IllegalStateException("CLI process not started");
-            }
-            return JsonRpcClient.fromProcess(process);
-        } else {
-            if (tcpHost == null || tcpPort == null) {
-                throw new IllegalStateException("Cannot connect because TCP host or port are not available");
-            }
+        if (tcpHost != null && tcpPort != null) {
+            // TCP mode: external server or child process with explicit port
             Socket socket = new Socket(tcpHost, tcpPort);
             return JsonRpcClient.fromSocket(socket);
+        } else if (process != null) {
+            // Stdio mode: child process
+            return JsonRpcClient.fromProcess(process);
+        } else {
+            throw new IllegalStateException("Cannot connect: no process for stdio and no host:port for TCP");
         }
     }
 

src/main/java/com/github/copilot/sdk/CopilotClient.java

@@ -90,10 +90,15 @@ public CopilotClient() {
     public CopilotClient(CopilotClientOptions options) {
         this.options = options != null ? options : new CopilotClientOptions();
 
-        // Validate mutually exclusive options
+        // When cliUrl is set, auto-correct useStdio since we're connecting via TCP
+        if (this.options.getCliUrl() != null && !this.options.getCliUrl().isEmpty()) {
+            this.options.setUseStdio(false);
+        }
+
+        // Validate mutually exclusive options: cliUrl and cliPath cannot both be set
         if (this.options.getCliUrl() != null && !this.options.getCliUrl().isEmpty()
-                && (this.options.isUseStdio() || this.options.getCliPath() != null)) {
-            throw new IllegalArgumentException("CliUrl is mutually exclusive with UseStdio and CliPath");
+                && this.options.getCliPath() != null) {
+            throw new IllegalArgumentException("CliUrl is mutually exclusive with CliPath");
         }
 
         // Validate auth options with external server

src/test/java/com/github/copilot/sdk/CopilotClientTest.java

@@ -96,16 +96,29 @@ void testClientConstructionWithOptions() {
     }
 
     @Test
-    void testCliUrlMutualExclusion() {
+    void testCliUrlAutoCorrectsUseStdio() {
         var options = new CopilotClientOptions().setCliUrl("localhost:3000").setUseStdio(true);
 
-        assertThrows(IllegalArgumentException.class, () -> new CopilotClient(options));
+        // Should NOT throw - useStdio is auto-corrected to false when cliUrl is set
+        var client = new CopilotClient(options);
+        assertFalse(options.isUseStdio(), "useStdio should be auto-corrected to false when cliUrl is set");
+        client.close();
+    }
+
+    @Test
+    void testCliUrlOnlyConstruction() {
+        var options = new CopilotClientOptions().setCliUrl("localhost:4321");
+
+        // Should work without explicitly setting useStdio to false
+        var client = new CopilotClient(options);
+        assertEquals(ConnectionState.DISCONNECTED, client.getState());
+        assertFalse(options.isUseStdio(), "useStdio should be auto-corrected to false when cliUrl is set");
+        client.close();
     }
 
     @Test
     void testCliUrlMutualExclusionWithCliPath() {
-        var options = new CopilotClientOptions().setCliUrl("localhost:3000").setCliPath("/path/to/cli")
-                .setUseStdio(false);
+        var options = new CopilotClientOptions().setCliUrl("localhost:3000").setCliPath("/path/to/cli");
 
         assertThrows(IllegalArgumentException.class, () -> new CopilotClient(options));
     }
@@ -194,16 +207,14 @@ void testExplicitUseLoggedInUserTrueWithGithubToken() {
 
     @Test
     void testGithubTokenWithCliUrlThrows() {
-        var options = new CopilotClientOptions().setCliUrl("localhost:8080").setGithubToken("gho_test_token")
-                .setUseStdio(false);
+        var options = new CopilotClientOptions().setCliUrl("localhost:8080").setGithubToken("gho_test_token");
 
         assertThrows(IllegalArgumentException.class, () -> new CopilotClient(options));
     }
 
     @Test
     void testUseLoggedInUserWithCliUrlThrows() {
-        var options = new CopilotClientOptions().setCliUrl("localhost:8080").setUseLoggedInUser(false)
-                .setUseStdio(false);
+        var options = new CopilotClientOptions().setCliUrl("localhost:8080").setUseLoggedInUser(false);
 
         assertThrows(IllegalArgumentException.class, () -> new CopilotClient(options));
     }