Bug in factoring of general symbolic expressions

[rwst]

sage: (sin(x)^2-1).factor()
(sin(x) + 1)*(sin(x) - 1)
sage: f(x) = function('f')(x)
sage: (f(x)^2-1).factor()
(f(x) + 1)*(f(x) - 1)
sage: f(x).diff(x)
diff(f(x), x)
sage: (f(x).diff(x)^2-1).factor()
...
NotImplementedError: derivative

sage: SR((f(x).diff(x)^2-1)._maxima_().factor())
(diff(f(x), x) + 1)*(diff(f(x), x) - 1)

factor() falls back to Maxima if it cannot convert the expression to a polynomial. It fails to catch NotImplementedError from expression_conversion.py however.

Component: symbolics

Author: Ralf Stephan

Branch/Commit: 2ea5c31

Reviewer: Marc Mezzarobba

Issue created by migration from https://trac.sagemath.org/ticket/21529

[rwst]

Branch: u/rws/bug_in_factoring_of_general_symbolic_expressions

[rwst]

Author: Ralf Stephan

[rwst]

Commit: 2ea5c31

[rwst]

New commits:

2ea5c31

21529: fix bug in factoring of general symbolic expressions

[mezzarobba]

Reviewer: Marc Mezzarobba

[vbraun]

Changed branch from u/rws/bug_in_factoring_of_general_symbolic_expressions to 2ea5c31