`grid_path_cells` can fail

[charleskawczynski]

I'm pretty sure that grid_path_cells is documented somewhere that it can fail, but I think it's worth opening an issue to make this function always work.

Reproducer:

import h3
c0 = h3.latlng_to_cell(41.141416500334635, -85.62262147756336, 3)
c1 = h3.latlng_to_cell(36.678141479650726, -105.4336830442914, 3)
h3.grid_path_cells(c0, c1)
>>> c0 = h3.latlng_to_cell(41.141416500334635, -85.62262147756336, 3)
>>> c1 = h3.latlng_to_cell(36.678141479650726, -105.4336830442914, 3)
>>> h3.grid_path_cells(c0, c1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/charleskawczynski/Documents/dev/.venv/lib/python3.12/site-packages/h3/api/basic_str/__init__.py", line 899, in grid_path_cells
    mv = _cy.grid_path_cells(_in_scalar(start), _in_scalar(end))
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h3/_cy/cells.pyx", line 323, in h3._cy.cells.grid_path_cells
  File "h3/_cy/cells.pyx", line 332, in h3._cy.cells.grid_path_cells
  File "h3/_cy/cells.pyx", line 321, in h3._cy.cells._could_not_find_line
  File "h3/_cy/error_system.pyx", line 231, in h3._cy.error_system.check_for_error_msg
h3._cy.error_system.H3FailedError: Couldn't find line between cells 0x832a96fffffffff and 0x8348dbfffffffff

[jlzamary]

I believe this Stack Overflow post address the issue and provides the following solution:

• Find all intersection points along the great arc between point A and point B.
• For each point, find the H3 index.
• Find the h3Line between each segment, e.g. h3Line(cellA, cellIntersection1), h3Line(cellIntersection1, cellIntersection2), and so on.
• Combine the lines, dropping duplicate indexes.

I'm currently running into the same issue and it does not look like the library has been updated to handle the error. I would be interested in any code you have to work around it.