broken p-adic getslice

[sagetrac-dmharvey]

(This ticket was split off from #2943)

This is okay:

sage: K = Qp(13,7)
sage: R.<t> = K[]       
sage: a = 13^7*t^3 + K(169,4)*t - 13^4
sage: a[1:2]
(13^2 + O(13^4))*t

This dies:

sage: t[0:1]
[boom]

The original context for this bug was along the lines of (see #2943 for more examples):

sage: K = Qp(p,10)
sage: C.<t> = LaurentSeriesRing(K)
sage: D.<s> = PolynomialRing(C)
sage: z = (1 + O(t)) + t*s^2
sage: z * z
[boom]

CC: @craigcitro

Component: basic arithmetic

Issue created by migration from https://trac.sagemath.org/ticket/3184

[sagetrac-mabshoff]

comment:2

Craig has become a getslice expert, so let's CC him :)

Cheers,

Michael

[roed314]

comment:3

Attachment: 3184.patch.gz

[jasongrout]

comment:4

First comment: getslice is deprecated; it should be __getitem__ now.

Second, there is a standard block of code for slicing...using that will make sure that things are consistent for people that understand python slices.

[sagetrac-dmharvey]

comment:5

Looks good to me.

[sagetrac-mabshoff]

comment:6

Merged in Sage 3.4.1.alpha0.

Cheeers,

Michael