bug in notebook (too much text clipped)

[williamstein]

bug in notebook:

  sage: sys.stdout.write('hi there')
  sage: sys.stdout.flush()
  hi ther
      ^^^^ ----- where's the e!!

Component: basic arithmetic

Issue created by migration from https://trac.sagemath.org/ticket/38

[boothby]

Try the following:

sys.stdout.write('hi there')
sleep(2)

While sage is sleep()ing, you'll see the full text. When it finishes, the e disappears. ?????

Messing with stdout from the notebook seems like a categorically bad idea. I've found that any of the following commands cause the notebook to hang.

sys.stdout.close()
sys.stdout.next()
sys.stdout.read()

I have found a trivial workaround. If we tack an extra print statement onto the end, it works fine. But why do we have to do this? Mysterious.

  sage: sys.stdout.write('hi there')
  sage: print
  hi there
         ^ ----- w00t

[williamstein]

comment:2

Fixed.

There was some interaction between the code that asks for an updated list of variables that have been defined and this problem.

I changed a few lines in sage/server/notebook/worksheet.py to the following:

        if not C.introspect():
            input += 'print "\\n\\n%s'%SAGE_VARS + '=%s"%_support_.variables(True)'