MAINT: Fix mypy errors (#2728)

Author: VeckoTheGecko

pyproject.toml

@@ -175,27 +175,19 @@ exclude = [
   "src/parcels/_core/utils/interpolation.py",
   "src/parcels/_core/utils/unstructured.py",
   "src/parcels/_core/particle.py",
-  "src/parcels/_core/field.py",
   "src/parcels/_core/kernel.py",
   "src/parcels/_core/particleset.py",
   "src/parcels/_core/xgrid.py",
-  "src/parcels/_core/warnings.py",
-  "src/parcels/_core/constants.py",
-  "src/parcels/_core/utils/sgrid.py",
-  "src/parcels/_core/utils/string.py",
   "src/parcels/_core/particlefile.py",
   "src/parcels/_core/uxgrid.py",
   "src/parcels/_core/spatialhash.py",
-  "src/parcels/_core/statuscodes.py",
   "src/parcels/_core/particlesetview.py",
   "src/parcels/_core/fieldset.py",
   "src/parcels/_core/index_search.py",
   "src/parcels/interpolators/_xinterpolators.py",
-  "src/parcels/interpolators/__init__.py",
   "src/parcels/interpolators/_uxinterpolators.py",
   "src/parcels/kernels/_sigmagrids.py",
   "src/parcels/kernels/_advectiondiffusion.py",
-  "src/parcels/kernels/__init__.py",
   "src/parcels/kernels/_advection.py",
 ]
 

src/parcels/_core/field.py

@@ -35,7 +35,7 @@ def _deal_with_errors(error, key, vector_type: VectorType):
     else:
         raise RuntimeError(f"{error}. Error could not be handled because particles was not part of the Field Sampling.")
 
-    if vector_type and "3D" in vector_type:
+    if vector_type == "3D":
         return (0, 0, 0)
     elif vector_type == "2D":
         return (0, 0)
@@ -219,7 +219,7 @@ def __init__(
             _assert_same_time_interval((U, V, W))
 
         self.time_interval = U.time_interval
-
+        self.vector_type: VectorType
         if self.W:
             self.vector_type = "3D"
         else:
@@ -285,7 +285,7 @@ def eval(self, time: datetime, z, y, x, particles=None):
             _update_particle_states_interp_value(particles, vel)
             _mask_outofbounds_values(grid_positions, vel)
 
-        if "3D" in self.vector_type:
+        if "3D" == self.vector_type:
             return (u, v, w)
         else:
             return (u, v)

src/parcels/_core/statuscodes.py

@@ -117,7 +117,7 @@ def __init__(self, particles, fieldset=None, msg=None):
         super().__init__(message)
 
 
-AllParcelsErrorCodes = {
+AllParcelsErrorCodes: dict[type[Exception], int] = {
     FieldInterpolationError: StatusCode.ErrorInterpolation,
     FieldOutOfBoundError: StatusCode.ErrorOutOfBounds,
     FieldOutOfBoundSurfaceError: StatusCode.ErrorThroughSurface,