fix: propagate resolved port to build when default port is unavailable (#2783)

* fix: propagate resolved port to build when default port is unavailable

When the default port (8081) is busy and the user accepts an alternative
port, the resolved port was only used to start Metro but not propagated
to args.port. This caused the iOS build (via RCT_METRO_PORT env var)
and Android build (via -PreactNativeDevServerPort and adb reverse) to
still use the original port, so the app would fail to connect to Metro.

* fix: return discovered port when packager is already running on a different port

When the default port is unavailable and `getNextPort` finds a packager
already running on a different port for the same project,
`handlePortUnavailable` correctly logs the discovered port but returns
the original (unavailable) port. This causes the build to pass the wrong
port to gradle/xcodebuild.

Author: janicduplessis

packages/cli-platform-android/src/commands/runAndroid/index.ts

@@ -70,6 +70,10 @@ async function runAndroid(_argv: Array<string>, config: Config, args: Flags) {
         args.terminal,
       );
     }
+
+    if (newPort !== port) {
+      args.port = newPort;
+    }
   }
 
   if (config.reactNativeVersion !== 'unknown') {

packages/cli-platform-apple/src/commands/runCommand/createRun.ts

@@ -124,6 +124,10 @@ const createRun =
           args.terminal,
         );
       }
+
+      if (newPort !== port) {
+        args.port = newPort;
+      }
     }
 
     if (ctx.reactNativeVersion !== 'unknown') {

packages/cli-tools/src/handlePortUnavailable.ts

@@ -18,6 +18,7 @@ const handlePortUnavailable = async (
 
   if (!start) {
     packager = false;
+    port = nextPort;
     logAlreadyRunningBundler(nextPort);
   } else {
     const {change} = await askForPortChange(port, nextPort);