Kummer surface functionality fails
Currently the creation of the Kummer surface associated to a genus 2 curve fails. All three of the final statements in the following code return the same error.
sage: R.<x> = QQ[]
sage: f = x^5 + x + 1
sage: X = HyperellipticCurve(f)
sage: J = Jacobian(X)
sage: K = KummerSurface(J)
sage: K = J.kummer_surface()
sage: phi = X.kummer_morphism()
Change History (8)
Cc: 
kohel slelievre added

Branch: 
→ u/chapoton/26151

Commit: 
→ 972750ff31e42e1cae9edfc3bd9f0cd672172006

Status: 
new →
needs_review

Commit: 
972750ff31e42e1cae9edfc3bd9f0cd672172006 →
3f5f59c8b7814443a358abbe1d8570c71c6b71b2

Authors: 
→ Frédéric Chapoton

Keywords: 
kummer added

Reviewers: 
→ Samuel Lelièvre

Status: 
needs_review →
positive_review

Milestone: 
sage8.4 →
sage8.9

Branch: 
u/chapoton/26151 →
3f5f59c8b7814443a358abbe1d8570c71c6b71b2

Resolution: 
→ fixed

Status: 
positive_review →
closed

Here is a fix.
Note an important change in the check inside the definition of projective morphisms..
New commits:
trac 26151 fix Kummer surface and add doctest