Ticket #3968 (closed defect: fixed)

Opened 3 months ago

Last modified 3 months ago

[with patch, positive review] Magma interface sometimes fails on long inputs

Reported by: kedlaya Assigned to: was
Priority: major Milestone: sage-3.1.2
Component: interfaces Keywords:
Cc:

Description

This fails: 

%magma
Qt<t> := RationalFunctionField(Rationals());
R<w,x,y,z> := PolynomialRing(Qt, 4);
P0 := w^3 + x^3 + y^3 + z^3;
P := P0 + (w+x)*(w+2*y)*(w+3*z) + x*y*z;
Pt := P0 + t*P;
Pt_gradient := [Derivative(Pt, w), Derivative(Pt, x), Derivative(Pt, y), Derivative(Pt, z)];
Pt_jac := IdealWithFixedBasis(Pt_gradient);
Pt_gradient_long := Append(Pt_gradient, (1+t)*w*x*y*z);
Pt_jac_long := IdealWithFixedBasis(Pt_gradient_long);
b := (1+t)*w*x*y*z;
diffbasis := [2*w*P, 2*x*P, 2*y*P, 2*z*P, 3*b*P];
temp := Coordinates(Pt_jac, diffbasis[5]);
diffbasis[5] := (Derivative(temp[1],w) + Derivative(temp[2],x) + \
    Derivative(temp[3],y) + Derivative(temp[4],z)) / (-3);

with the error: 

   File "<ipython console>", line 1
     logstr(r"""Loading "/home/r1/kedlaya/.sage//temp/DWORK.MIT.EDU/22570//interface//tmp"""")
                                                                                             ^
SyntaxError: EOL while scanning single-quoted string

but if you replace the last two lines by 

diffbasis[5] := (Derivative(temp[1],w) + Derivative(temp[2],x) + Derivative(temp[3],y))/(-3);

then nothing breaks.

Attachments

parser.patch (0.7 kB) - added by jason on 08/27/2008 12:27:32 PM.

Change History

08/27/2008 10:31:47 AM changed by jason

From IRC 

[12:20] <jason_> my error has:
[12:20] <jason_>    File "<ipython console>", line 1
[12:20] <jason_>      logstr(r"""Loading "/home/jason/.sage//temp/sage/4426//interface//tmp4426"""")
[12:20] <kedlaya> yeah, I see something similar
[12:20] <jason_> I think that last """" is the problem
[12:20] <jason_> is it being parsed as " """
[12:20] <jason_> or as """ "
[12:21] <wjp> funny that that error message has a "# TODO: this is a very lazy temporary bug fix" above the line in the sources
[12:21] <kedlaya> too lazy, i guess
[12:21] <wjp> (sage/misc/preparser_ipython.py, search for logstr)
[12:21] <kedlaya> i wonder if I can find the ticket for it
[12:21] <jason_> wjp: if you have the sources, can you put a space in between the " and the """ ?
[12:22] <wjp> the line is return 'logstr(r"""%s""")'%t, but I'll add a space after the %s
[12:23] <wjp> works now
[12:23] <jason_> okay, now time for the ticket :)
[12:23] <kedlaya> I'm working on it now
[12:23] <jason_> from http://docs.python.org/ref/strings.html
[12:23] <jason_> In triple-quoted strings, unescaped newlines and quotes are allowed (and are retained), except that three unescaped quotes in a row terminate the string. (A ``quote'' is the character used to open the string, i.e. either ' or ".) 
[12:23] <jason_> so apparently the first three """ terminated the string
[12:24] <wjp> yes
[12:24] <kedlaya> ticket #3968 created. Now go fix it. :)

08/27/2008 10:40:43 AM changed by jason

  • summary changed from Magma interface sometimes fails on long inputs to [with patch, needs review] Magma interface sometimes fails on long inputs.

08/27/2008 12:22:51 PM changed by jason

Updated patch to escape strings rather than hoping they don't contain triple quotes.

08/27/2008 12:27:32 PM changed by jason

  • attachment parser.patch added.

08/27/2008 12:28:12 PM changed by jason

Okay, again updated to use the much simpler solution: %r instead of %s.

08/27/2008 12:32:47 PM changed by wjp

  • summary changed from [with patch, needs review] Magma interface sometimes fails on long inputs to [with patch, positive review] Magma interface sometimes fails on long inputs.

08/27/2008 01:45:29 PM changed by mabshoff

  • milestone set to sage-3.1.2.

Shouldn't we add a doctest that tests for the case that Kiran discovered?

Cheers,

Michael

08/27/2008 02:05:02 PM changed by mabshoff

For the record: doctests pass with the patch applied.

Cheers,

Michael

08/27/2008 02:15:02 PM changed by wjp

For a potential doctest, this is easy to trigger with the singular interface too: 

sage: %singular

  --> Switching to Singular <-- 

''
singular: print("\"test\"")
------------------------------------------------------------
   File "<ipython console>", line 1
     logstr(r""""test"""")
                         ^
SyntaxError: EOL while scanning single-quoted string

08/28/2008 01:40:00 PM changed by mabshoff

  • status changed from new to closed.
  • resolution set to fixed.

Merged in Sage 3.1.2.alpha2