From cc4ac99b4a69f2e2fa5372f72999cac27d1a4274 Mon Sep 17 00:00:00 2001
From: Tenith01 <hasintha199@gmail.com>
Date: Tue, 17 Mar 2026 13:02:55 +0530
Subject: [PATCH] fix: show actionable error when server port is already in use

---
 src/main.zig | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/main.zig b/src/main.zig
index 26e29b22..0196bb7f 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -94,7 +94,16 @@ fn run(allocator: Allocator, main_arena: Allocator) !void {
             };
 
             var server = lp.Server.init(app, address) catch |err| {
-                log.fatal(.app, "server run error", .{ .err = err });
+                if (err == error.AddressInUse) {
+                    log.fatal(.app, "address already in use", .{
+                        .host = opts.host,
+                        .port = opts.port,
+                        .hint = "Another process is already listening on this address. " ++
+                            "Stop the other process or use --port to choose a different port.",
+                    });
+                } else {
+                    log.fatal(.app, "server run error", .{ .err = err });
+                }
                 return err;
             };
             defer server.deinit();