If sys.trace is None, don't trace. For exceptions, only use

the local trace function.

diff --git a/Python/ceval.c b/Python/ceval.c
index cc2f034b798c93be11d7e8ed361a318a44009e64..fc217066f0bcd463475e419ffa90cfdcec1c50e9 100644 (file)
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -159,6 +159,10 @@ eval_code(co, globals, locals, arg)
 
        trace = sysget("trace");
        if (trace != NULL) {
+         if (trace == None) {
+               trace = NULL;
+         }
+         else {
                /* sys.trace, if defined, is a function that will
                   be called  on *every* entry to a code block.
                   Its return value, if not None, is a function that
@@ -184,6 +188,7 @@ eval_code(co, globals, locals, arg)
                        DECREF(trace);
                        trace = NULL;
                }
+         }
        }
        
        next_instr = GETUSTRINGVALUE(f->f_code->co_code);
@@ -1057,11 +1062,7 @@ eval_code(co, globals, locals, arg)
                                f->f_lasti -= 2;
                        tb_here(f);
 
-                       if (trace)
-                               v = trace;
-                       else
-                               v = sysget("trace");
-                       if (v) {
+                       if (trace) {
                                object *type, *value, *traceback, *arg;
                                err_get(&type, &value);
                                traceback = tb_fetch();
@@ -1073,7 +1074,7 @@ eval_code(co, globals, locals, arg)
                                        settupleitem(arg, 1, value);
                                        settupleitem(arg, 2, traceback);
                                }
-                               v = call_trace(v, f, "exception", arg);
+                               v = call_trace(trace, f, "exception", arg);
                                if (v == NULL) {
                                        /* Trace function raised error */
                                        tb_here(f);