Address Jelle's review

Author: StanFromIreland

Modules/readline.c

@@ -1513,7 +1513,9 @@ flex_complete(const char *text, int start, int end)
         if (begidx == NULL || endidx == NULL) {
             Py_XDECREF(begidx);
             Py_XDECREF(endidx);
-            PyErr_Clear();
+            PyErr_FormatUnraisable("Exception ignored while preparing "
+                                   "readline completion");
+            rl_attempted_completion_over = 1;
             PyGILState_Release(gilstate);
             return NULL;
         }

Python/ceval.c

@@ -1229,8 +1229,11 @@ dtrace_function_entry(_PyInterpreterFrame *frame)
     filename = PyUnicode_AsUTF8(code->co_filename);
     funcname = PyUnicode_AsUTF8(code->co_name);
     PyErr_SetRaisedException(exc);
-    if (filename == NULL || funcname == NULL) {
-        return;
+    if (filename == NULL) {
+        filename = "<unknown>";
+    }
+    if (funcname == NULL) {
+        funcname = "<unknown>";
     }
     lineno = PyUnstable_InterpreterFrame_GetLine(frame);
 
@@ -1249,8 +1252,11 @@ dtrace_function_return(_PyInterpreterFrame *frame)
     filename = PyUnicode_AsUTF8(code->co_filename);
     funcname = PyUnicode_AsUTF8(code->co_name);
     PyErr_SetRaisedException(exc);
-    if (filename == NULL || funcname == NULL) {
-        return;
+    if (filename == NULL) {
+        filename = "<unknown>";
+    }
+    if (funcname == NULL) {
+        funcname = "<unknown>";
     }
     lineno = PyUnstable_InterpreterFrame_GetLine(frame);