[Python-ideas] Shrink recursion error tracebacks (was: Have REPL print less by default)

Jonathan Goble jcgoble3 at gmail.com
Wed Apr 20 02:41:02 EDT 2016

On Wed, Apr 20, 2016 at 2:19 AM, Terry Reedy <tjreedy at udel.edu> wrote:
> On 4/20/2016 12:07 AM, Émanuel Barry wrote:
>> This idea was mentioned a couple of times in the previous thread, and it
>> seems reasonable to me. Getting recursion errors when testing a function
>> in
>> the interactive prompt often screwed me over, as I have a limited
>> scrollback
>> of 1000 lines at best on Windows (I never checked exactly how high/low the
>> limit was), and with Python's recursion limit of 1000, that's a whopping
>> 1000 to 2000 lines in my console, effectively killing off anything useful
>> I
>> might have wanted to see. Such as, for example, the function definition
>> that
>> triggered the exception.
> For those who don't know, the Windows console uses a circular buffer of
> lines.  The default size was once 300, I believe -- too small to contain a
> run of the test suite.  (I seems to be less on Win 10).  The max with win 10
> appears to be 999 (x 4? unclear).

I'm guessing you pulled the 999x4 from the Options tab of the
properties dialog, but that option is actually for command history
(i.e. the ability to use the up arrow to recall previous commands).
That has a limit of 999 commands in the buffer, with a limit of 999
(not 4, which is the default) total buffers in memory across all open
CMD.EXE instances. (Not sure what happens when you open more instances
than that limit is set to.)

The setting for scrollback is found under the Layout tab, and is
disguised as the Height option in the Screen Buffer Size section. That
has a limit of 9,999 lines, and I do believe it defaulted to 300 (I
changed that setting so long ago that I no longer remember for sure
what the stock default was).

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