py: Fix adding of traceback so that it appends to existing info.

This makes exception traceback info self contained (ie doesn't rely on
list object, which was a bit of a hack), reduces code size, and reduces
RAM footprint of exception by eliminating the list object.

Addresses part of issue #1126.

1 files changed, 21 insertions, 5 deletions

diff --git a/tests/misc/print_exception.py b/tests/misc/print_exception.py
index e65b8d1ac5..4e23bf1543 100644
--- a/tests/misc/print_exception.py
+++ b/tests/misc/print_exception.py
@@ -6,19 +6,35 @@ else:
     import traceback
     print_exception = lambda e, f: traceback.print_exception(None, e, None, file=f)
 
-try:
-    XXX
-except Exception as e:
-    print('caught')
+def print_exc(e):
     buf = io.StringIO()
     print_exception(e, buf)
     s = buf.getvalue()
     for l in s.split("\n"):
         # uPy on pyboard prints <stdin> as file, so remove filename.
         if l.startswith("  File "):
-            print(l[:8], l[-23:])
+            l = l.split('"')
+            print(l[0], l[2])
         # uPy and CPy tracebacks differ in that CPy prints a source line for
         # each traceback entry. In this case, we know that offending line
         # has 4-space indent, so filter it out.
         elif not l.startswith("    "):
             print(l)
+
+# basic exception message
+try:
+    XXX
+except Exception as e:
+    print('caught')
+    print_exc(e)
+
+# exception message with more than 1 source-code line
+def f():
+    g()
+def g():
+    YYY
+try:
+    f()
+except Exception as e:
+    print('caught')
+    print_exc(e)