Remove gdspy (#2477)

* refactor: remove gdspy

* docs: update notebooks and add changelog entry

* style: remove unnecessary comment directives

* style: remove unnecessary comments

* style: remove comments

* style: remove comment

* docs: update notebooks submodule

* docs: update notebooks due to rebase on develop

---------

Co-authored-by: Dario Quintero (Flexcompute) <149674618+daquinteroflex@users.noreply.github.com>

Author: frederikschubertflex

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 - Relaxed bounds checking of path integrals during `WavePort` validation.
 - Internal adjoint helper methods are now prefixed with an underscore to separate them from the public API.
+- Drop the dependency on `gdspy`, which has been unmaintained for over two years. Interfaces previously relying on `gdspy` now use its maintained successor, `gdstk`, with equivalent functionality.
 - Small (around 1e-4) numerical precision improvements in EME solver.
 
 ## [2.8.4] - 2025-05-15
@@ -33,7 +34,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Warn if more than 20 frequencies are used in EME, as this may lead to slower or more expensive simulations.
 - EME now supports 2D simulations.
 - 'EMESimulation' now supports 'PermittivityMonitor'.
-- Change `VisualizationSpec` validator for checking validity of user specified colors to only issue a warning if matplotlib is not installed instead of an error.
 
 ### Fixed
 - Fixed issue with `CustomMedium` gradients where other frequencies would wrongly contribute to the gradient.

docs/development/recommendations.rst

@@ -82,7 +82,7 @@ Managing Optional Dependencies On-The-Fly
 
 If you look within ``pyproject.toml``, it is possible to see that we have different packages relating to different functionalities that are optional.
 
-Some examples from these are ``[vtk, jax, trimesh, gdstk, gdspy]`` etc. What we want to do is improve the import speed of the core-package in order to minimise small core operations. As we scale into a bigger package, decoupling these type of imports from the total pacakge import is essential.
+Some examples from these are ``[vtk, jax, trimesh, gdstk]`` etc. What we want to do is improve the import speed of the core-package in order to minimise small core operations. As we scale into a bigger package, decoupling these type of imports from the total pacakge import is essential.
 
 
 Benchmarking Package Import
@@ -94,4 +94,4 @@ We have a set of utilties to verify this.
 
 .. code::
 
-    poetry run tidy3d develop benchmark-timing-operations
+    poetry run tidy3d develop benchmark-timing-operations

docs/install.rst

@@ -187,7 +187,6 @@ Tidy3D has several optional dependencies that provide additional functionality.
 
 Where ``dependency_group`` is one of the following:
 
-- ``gdspy``: Adds support for GDS export using `gdspy <https://github.com/heitzmann/gdspy>`_.
 - ``gdstk``: Adds support for GDS export using `gdstk <https://github.com/heitzmann/gdstk>`_.
 - ``trimesh``: Support for more complex mesh handling and manipulation.
 - ``vtk``: Support for working with unstructured data.

docs/notebooks

@@ -66,9 +66,6 @@ pytest-cov = "^6.0.0"
 pytest-env = "^1.1.5"
 tox = { version = "*", optional = true }
 
-# gdspy
-gdspy = { version = "*", optional = true }
-
 # gdstk
 gdstk = { version = ">=0.9.49", optional = true }
 
@@ -132,7 +129,6 @@ dev = [
   "coverage",
   'dill',
   'divparams',
-  'gdspy',
   'gdstk',
   'grcwa',
   'ipython',
@@ -210,7 +206,6 @@ docs = [
   "devsim",
   "cma",
 ]
-gdspy = ["gdspy"]
 gdstk = ["gdstk"]
 scikit-rf = ["scikit-rf"]
 trimesh = ["trimesh", "networkx", "rtree"]

poetry.lock

@@ -3,7 +3,6 @@
 import math
 import warnings
 
-import gdspy
 import gdstk
 import matplotlib.pyplot as plt
 import numpy as np
@@ -379,14 +378,6 @@ def test_gdstk_cell():
         )
 
 
-def test_gdspy_cell():
-    gds_cell = gdspy.Cell("name")
-    gds_cell.add(gdspy.Rectangle((0, 0), (1, 1)))
-    td.PolySlab.from_gds(gds_cell=gds_cell, axis=2, slab_bounds=(-1, 1), gds_layer=0)
-    with pytest.raises(Tidy3dKeyError):
-        td.PolySlab.from_gds(gds_cell=gds_cell, axis=2, slab_bounds=(-1, 1), gds_layer=1)
-
-
 def make_geo_group():
     """Make a generic Geometry Group."""
     boxes = [td.Box(size=(1, 1, 1), center=(i, 0, 0)) for i in range(-5, 5)]

pyproject.toml

@@ -2022,20 +2022,6 @@ def test_to_gds(tmp_path):
     polys = sim.to_gdstk(z=0, permittivity_threshold=6, frequency=200e14)
     assert len(polys) > 0
 
-    # to_gdspy() does not support custom medium
-    sim = make_sim(
-        permittivity=EPS,
-        size=SIZE,
-        vertices=VERTICES,
-        base_eps_val=BASE_EPS_VAL,
-        custom_medium=False,
-    )
-    polys = sim.to_gdspy(z=0)
-    assert len(polys) > 0
-
-    polys = sim.to_gdspy(y=0)
-    assert len(polys) > 4
-
 
 @pytest.mark.parametrize(
     "base_vertices",