[lldb] Fix that SIGWINCH crashes IOHandlerEditline when we are not us…

lldb/source/Core/IOHandler.cpp

@@ -289,7 +289,8 @@ void IOHandlerEditline::Deactivate() {
 
 void IOHandlerEditline::TerminalSizeChanged() {
 #if LLDB_ENABLE_LIBEDIT
-  m_editline_up->TerminalSizeChanged();
+  if (m_editline_up)
+    m_editline_up->TerminalSizeChanged();
 #endif
 }
 

lldb/test/API/iohandler/resize/TestIOHandlerResizeNoEditline.py

@@ -0,0 +1,21 @@
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+class TestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @no_debug_info_test
+    def test_resize_no_editline(self):
+        """ Tests terminal resizing if the editline isn't used. """
+        dbg = lldb.SBDebugger.Create(False)
+        # Set the input handle to some stream so that we don't start the
+        # editline interface.
+        dbg.SetInputFileHandle(io.BytesIO(b""), True)
+        opts = lldb.SBCommandInterpreterRunOptions()
+        # Launch the command interpreter now.
+        dbg.RunCommandInterpreter(True, True, opts, 0, False, False)
+        # Try resizing the terminal which shouldn't crash.
+        dbg.SetTerminalWidth(47)