pygmt.grdsample: Add check and test for exclusive parameters 'toggle' and 'registration'

pygmt/src/grdsample.py

@@ -9,6 +9,7 @@
 from pygmt._typing import PathLike
 from pygmt.alias import Alias, AliasSystem
 from pygmt.clib import Session
+from pygmt.exceptions import GMTInvalidInput
 from pygmt.helpers import (
     build_arg_list,
     deprecate_parameter,
@@ -70,6 +71,7 @@ def grdsample(
         Toggle between grid and pixel registration; if the input is grid-registered, the
         output will be pixel-registered and vice-versa. This is a *destructive* grid
         change; see :gmt-docs:`reference/options.html#switch-registrations`.
+        *Note**: ``toggle`` and ``registration`` are mutually exclusive.
     {verbose}
     {coltypes}
     {interpolation}
@@ -97,6 +99,15 @@ def grdsample(
     >>> # and set both x- and y-spacings to 0.5 arc-degrees
     >>> new_grid = pygmt.grdsample(grid=grid, toggle=True, spacing=[0.5, 0.5])
     """
+    # Enforce mutual exclusivity between -T (toggle) and -r (registration)
+    if kwargs.get("T", toggle) and (
+        "r" in kwargs
+        or "registration" in kwargs
+        or registration in ("gridline", "pixel")
+    ):
+        msg = "Parameters 'toggle' and 'registration' cannot be used together."
+        raise GMTInvalidInput(msg)
+
     aliasdict = AliasSystem(
         T=Alias(toggle, name="toggle"),
     ).add_common(

pygmt/tests/test_grdsample.py

@@ -8,6 +8,7 @@
 import xarray as xr
 from pygmt import grdsample
 from pygmt.enums import GridRegistration, GridType
+from pygmt.exceptions import GMTInvalidInput
 from pygmt.helpers import GMTTempFile
 from pygmt.helpers.testing import load_static_earth_relief
 
@@ -94,3 +95,11 @@ def test_grdsample_registration_changes(grid):
     assert translated_grid.gmt.registration is GridRegistration.GRIDLINE
     registration_grid = grdsample(grid=translated_grid, registration="pixel")
     assert registration_grid.gmt.registration is GridRegistration.PIXEL
+
+
+def test_grdsample_toggle_and_registration_mutually_exclusive(grid):
+    """
+    Raise an exception if toggle and registration are both set.
+    """
+    with pytest.raises(GMTInvalidInput):
+        grdsample(grid=grid, toggle=True, registration="pixel")