[nnbd] Reland backporting socket option semantics from NNBD dart:io.

The Socket class will now throw a SocketException if the socket has been
destroyed or upgraded to a secure socket upon setting or getting socket
options.

The NNBD migration required making subtle changes to some dart:io
semantics in order to provide a better API. This change backports one of
these semantic changes to the unmigrated SDK so any issues can be
discovered now instead of blocking the future SDK unfork.

Change-Id: If7029f8b42fd4b05cfb79eb439c09dc206dd3b92
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/134328
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>
Commit-Queue: Jonas Termansen <sortie@google.com>

CHANGELOG.md

@@ -17,6 +17,11 @@ used (see Issue [39627][]).
 
 #### `dart:io`
 
+* The `Socket` class will now throw a `SocketException` if the socket has been
+  destroyed or upgraded to a secure socket upon setting or getting socket
+  options. Previously setting a socket options would be ignored and getting a
+  socket option would return `null`.
+
 ### Dart VM
 
 ### Tools

sdk/lib/_internal/vm/bin/socket_patch.dart

@@ -1779,40 +1779,37 @@ class _Socket extends Stream<Uint8List> implements Socket {
   }
 
   bool setOption(SocketOption option, bool enabled) {
-    if (_raw == null) return false;
+    if (_raw == null) throw const SocketException.closed();
     return _raw.setOption(option, enabled);
   }
 
   Uint8List getRawOption(RawSocketOption option) {
-    if (_raw == null) return null;
+    if (_raw == null) throw const SocketException.closed();
     return _raw.getRawOption(option);
   }
 
   void setRawOption(RawSocketOption option) {
-    _raw?.setRawOption(option);
+    if (_raw == null) throw const SocketException.closed();
+    _raw.setRawOption(option);
   }
 
   int get port {
     if (_raw == null) throw const SocketException.closed();
-    ;
     return _raw.port;
   }
 
   InternetAddress get address {
     if (_raw == null) throw const SocketException.closed();
-    ;
     return _raw.address;
   }
 
   int get remotePort {
     if (_raw == null) throw const SocketException.closed();
-    ;
     return _raw.remotePort;
   }
 
   InternetAddress get remoteAddress {
     if (_raw == null) throw const SocketException.closed();
-    ;
     return _raw.remoteAddress;
   }
 

sdk/lib/io/socket.dart

@@ -652,21 +652,29 @@ abstract class RawSocket implements Stream<RawSocketEvent> {
 
   /**
    * Returns the port used by this socket.
+   *
+   * Throws a [SocketException] if the socket is closed.
    */
   int get port;
 
   /**
    * Returns the remote port connected to by this socket.
+   *
+   * Throws a [SocketException] if the socket is closed.
    */
   int get remotePort;
 
   /**
    * Returns the [InternetAddress] used to connect this socket.
+   *
+   * Throws a [SocketException] if the socket is closed.
    */
   InternetAddress get address;
 
   /**
    * Returns the remote [InternetAddress] connected to by this socket.
+   *
+   * Throws a [SocketException] if the socket is closed.
    */
   InternetAddress get remoteAddress;
 
@@ -791,6 +799,9 @@ abstract class Socket implements Stream<Uint8List>, IOSink {
    * available options.
    *
    * Returns [:true:] if the option was set successfully, false otherwise.
+   *
+   * Throws a [SocketException] if the socket has been destroyed or upgraded to
+   * a secure socket.
    */
   bool setOption(SocketOption option, bool enabled);
 
@@ -800,7 +811,8 @@ abstract class Socket implements Stream<Uint8List>, IOSink {
    *
    * Returns the [RawSocketOption.value] on success.
    *
-   * Throws an [OSError] on failure.
+   * Throws an [OSError] on failure and a [SocketException] if the socket has
+   * been destroyed or upgraded to a secure socket.
    */
   Uint8List getRawOption(RawSocketOption option);
 
@@ -808,27 +820,36 @@ abstract class Socket implements Stream<Uint8List>, IOSink {
    * Use [setRawOption] to customize the [RawSocket]. See [RawSocketOption] for
    * available options.
    *
-   * Throws an [OSError] on failure.
+   * Throws an [OSError] on failure and a [SocketException] if the socket has
+   * been destroyed or upgraded to a secure socket.
    */
   void setRawOption(RawSocketOption option);
 
   /**
    * Returns the port used by this socket.
+   *
+   * Throws a [SocketException] if the socket is closed.
    */
   int get port;
 
   /**
    * Returns the remote port connected to by this socket.
+   *
+   * Throws a [SocketException] if the socket is closed.
    */
   int get remotePort;
 
   /**
    * Returns the [InternetAddress] used to connect this socket.
+   *
+   * Throws a [SocketException] if the socket is closed.
    */
   InternetAddress get address;
 
   /**
    * Returns the remote [InternetAddress] connected to by this socket.
+   *
+   * Throws a [SocketException] if the socket is closed.
    */
   InternetAddress get remoteAddress;