fix(cmd_sub): Prevent crash with malformed JID in /sub command

Added null check for jidp in cmd_sub to handle jid_create returning NULL.

Crash occurred when processing malformed JID inputs like @example.com.

Ensures robust handling of invalid JIDs.

Fixes #22

src/command/cmd_funcs.c

@@ -1263,6 +1263,11 @@ cmd_sub(ProfWin* window, const char* const command, gchar** args)
 
     auto_jid Jid* jidp = jid_create(jid);
 
+    if (jidp == NULL) {
+        cons_show("Malformed JID: %s", jid);
+        return TRUE;
+    }
+
     if (strcmp(subcmd, "allow") == 0) {
         presence_subscription(jidp->barejid, PRESENCE_SUBSCRIBED);
         cons_show("Accepted subscription for %s", jidp->barejid);

tests/unittests/test_cmd_sub.c

@@ -40,3 +40,16 @@ cmd_sub_shows_usage_when_no_arg(void** state)
     gboolean result = cmd_sub(NULL, CMD_SUB, args);
     assert_true(result);
 }
+
+void
+test_cmd_sub_malformed_jid(void** state)
+{
+    ProfWin win;
+    gchar* args[] = { "request", "@example.com" };
+
+    will_return(connection_get_status, JABBER_CONNECTED);
+
+    expect_cons_show("Malformed JID: @example.com");
+    gboolean result = cmd_sub((ProfWin*)&win, CMD_SUB, args);
+    assert_true(result);
+}

tests/unittests/test_cmd_sub.h

@@ -1,2 +1,3 @@
 void cmd_sub_shows_message_when_not_connected(void** state);
 void cmd_sub_shows_usage_when_no_arg(void** state);
+void test_cmd_sub_malformed_jid(void** state);

tests/unittests/unittests.c

@@ -386,6 +386,7 @@ main(int argc, char* argv[])
 
         cmocka_unit_test(cmd_sub_shows_message_when_not_connected),
         cmocka_unit_test(cmd_sub_shows_usage_when_no_arg),
+        cmocka_unit_test(test_cmd_sub_malformed_jid),
 
         cmocka_unit_test(contact_in_group),
         cmocka_unit_test(contact_not_in_group),