Improve error handling in g2c

[roed314]

Should resolve this error from the flasklog:

Exception on /Genus2Curve/Q/coeffs=[1,4,6,2,1,2,1] [GET]
Traceback (most recent call last):
  File "/home/lmfdb/lmfdb-git-web/lmfdb/genus2_curves/main.py", line 543, in genus2_jump
    rhs_poly = coeff_to_poly_multi(rhs_str)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/utils/utilities.py", line 269, in coeff_to_poly_multi
    return PolynomialRing(QQ, list(varposs))(c)
  File "/home/sage/sage-10.4/src/sage/rings/polynomial/multi_polynomial_ring.py", line 511, in __call__
    return self(x)
  File "/home/sage/sage-10.4/src/sage/rings/polynomial/multi_polynomial_ring.py", line 542, in __call__
    c = self.base_ring()(x)
  File "sage/structure/parent.pyx", line 908, in sage.structure.parent.Parent.__call__
    return mor._call_(x)
  File "sage/structure/coerce_maps.pyx", line 164, in sage.structure.coerce_maps.DefaultConvertMap_unique._call_
    raise
  File "sage/structure/coerce_maps.pyx", line 159, in sage.structure.coerce_maps.DefaultConvertMap_unique._call_
    return C._element_constructor(x)
  File "sage/rings/rational.pyx", line 555, in sage.rings.rational.Rational.__init__
    self.__set_value(x, base)
  File "sage/rings/rational.pyx", line 700, in sage.rings.rational.Rational._Rational__set_value
    raise TypeError("unable to convert {!r} to a rational".format(x))
TypeError: unable to convert [1, 4, 6, 2, 1, 2, 1] to a rational

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/lmfdb/lmfdb-git-web/lmfdb/utils/search_wrapper.py", line 165, in __call__
    return func(info)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/genus2_curves/main.py", line 548, in genus2_jump
    flash_error(errmsg, main_poly_str)
UnboundLocalError: local variable 'main_poly_str' referenced before assignment

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 2073, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 1519, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 1517, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 1503, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/genus2_curves/main.py", line 324, in by_label
    return genus2_curve_search({"jump": label})
  File "/home/lmfdb/lmfdb-git-web/lmfdb/utils/search_wrapper.py", line 177, in __call__
    return render_template(
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/templating.py", line 154, in render_template
    return _render(
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/templating.py", line 128, in _render
    rv = template.render(context)
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/jinja2/environment.py", line 1304, in render
    self.environment.handle_exception()
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/jinja2/environment.py", line 939, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/search_results.html", line 1, in top-level template code
    {% extends 'homepage.html' %}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/homepage.html", line 5, in top-level template code
    {{CodeSnippet(code, item).place_code()}}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/base.html", line 186, in top-level template code
    {% block body -%}{%- endblock body %}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/homepage.html", line 207, in block 'body'
    {% block content -%}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/search_results.html", line 4, in block 'content'
    {% include 'refine_search_form.html' %}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/refine_search_form.html", line 20, in top-level template code
    {% if info.search_array.has_advanced_inputs(info) %}
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/jinja2/environment.py", line 487, in getattr
    return getattr(obj, attribute)
jinja2.exceptions.UndefinedError: 'dict object' has no attribute 'search_array'
[2025-07-28 07:09:28 UTC] 500 error on URL https://www.lmfdb.org/Genus2Curve/Q/coeffs%3D%5B1,4,6,2,1,2,1%5D ()
Exception on /Genus2Curve/Q/coeffs=[1,4,6,2,1,2,1] [GET]
Traceback (most recent call last):
  File "/home/lmfdb/lmfdb-git-web/lmfdb/genus2_curves/main.py", line 543, in genus2_jump
    rhs_poly = coeff_to_poly_multi(rhs_str)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/utils/utilities.py", line 269, in coeff_to_poly_multi
    return PolynomialRing(QQ, list(varposs))(c)
  File "/home/sage/sage-10.4/src/sage/rings/polynomial/multi_polynomial_ring.py", line 511, in __call__
    return self(x)
  File "/home/sage/sage-10.4/src/sage/rings/polynomial/multi_polynomial_ring.py", line 542, in __call__
    c = self.base_ring()(x)
  File "sage/structure/parent.pyx", line 908, in sage.structure.parent.Parent.__call__
    return mor._call_(x)
  File "sage/structure/coerce_maps.pyx", line 164, in sage.structure.coerce_maps.DefaultConvertMap_unique._call_
    raise
  File "sage/structure/coerce_maps.pyx", line 159, in sage.structure.coerce_maps.DefaultConvertMap_unique._call_
    return C._element_constructor(x)
  File "sage/rings/rational.pyx", line 555, in sage.rings.rational.Rational.__init__
    self.__set_value(x, base)
  File "sage/rings/rational.pyx", line 700, in sage.rings.rational.Rational._Rational__set_value
    raise TypeError("unable to convert {!r} to a rational".format(x))
TypeError: unable to convert [1, 4, 6, 2, 1, 2, 1] to a rational

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/lmfdb/lmfdb-git-web/lmfdb/utils/search_wrapper.py", line 165, in __call__
    return func(info)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/genus2_curves/main.py", line 548, in genus2_jump
    flash_error(errmsg, main_poly_str)
UnboundLocalError: local variable 'main_poly_str' referenced before assignment

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 2073, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 1519, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 1517, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 1503, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/genus2_curves/main.py", line 324, in by_label
    return genus2_curve_search({"jump": label})
  File "/home/lmfdb/lmfdb-git-web/lmfdb/utils/search_wrapper.py", line 177, in __call__
    return render_template(
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/templating.py", line 154, in render_template
    return _render(
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/templating.py", line 128, in _render
    rv = template.render(context)
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/jinja2/environment.py", line 1304, in render
    self.environment.handle_exception()
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/jinja2/environment.py", line 939, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/search_results.html", line 1, in top-level template code
    {% extends 'homepage.html' %}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/homepage.html", line 5, in top-level template code
    {{CodeSnippet(code, item).place_code()}}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/base.html", line 186, in top-level template code
    {% block body -%}{%- endblock body %}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/homepage.html", line 207, in block 'body'
    {% block content -%}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/search_results.html", line 4, in block 'content'
    {% include 'refine_search_form.html' %}
  File "/home/lmfdb/lmfdb-git-web/lmfdb/templates/refine_search_form.html", line 20, in top-level template code
    {% if info.search_array.has_advanced_inputs(info) %}
  File "/home/sage/sage-10.4/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/jinja2/environment.py", line 487, in getattr
    return getattr(obj, attribute)
jinja2.exceptions.UndefinedError: 'dict object' has no attribute 'search_array'
[2025-07-28 07:09:29 UTC] 500 error on URL https://www.lmfdb.org/Genus2Curve/Q/coeffs%3D%5B1,4,6,2,1,2,1%5D ()