fix: two small bugs of the thickness and basal contacts tools

- extract_basal_contacts had a mutable default (ignore_units=[]) and
  added None to it, so the list grew at each call. It also changed the
  list of the caller. Use None and a new list.
- The thickness algorithm read MAX_LINE_LENGTH with parameterAsSource, so
  StructuralPoint always got None. Use parameterAsDouble.

Author: lachlangrose

loopstructural/main/m2l_api.py

@@ -249,7 +249,7 @@ def extract_basal_contacts(
     geology,
     stratigraphic_order,
     faults=None,
-    ignore_units=[],
+    ignore_units=None,
     unit_name_field=None,
     all_contacts=False,
     updater=None,
@@ -320,7 +320,8 @@ def extract_basal_contacts(
             geology = geology.drop(columns=['UNITNAME'])
         geology = geology.rename(columns={unit_name_field: 'UNITNAME'})
     # Log parameters via DebugManager if provided
-    ignore_units += [None]
+    # a new list: do not change the list of the caller
+    ignore_units = list(ignore_units or []) + [None]
 
     # Units in the geology layer that are not in the stratigraphic column are
     # kept in the geology (so they still bound the other units and appear in

loopstructural/processing/algorithms/thickness_calculator.py

@@ -260,7 +260,7 @@ def processAlgorithm(
         thickness_type = ['InterpolatedStructure', 'StructuralPoint'][thickness_type_index]
         dtm_data = self.parameterAsRasterLayer(parameters, self.INPUT_DTM, context)
         bounding_box_type = self.parameterAsEnum(parameters, self.INPUT_BOUNDING_BOX_TYPE, context)
-        max_line_length = self.parameterAsSource(parameters, self.INPUT_MAX_LINE_LENGTH, context)
+        max_line_length = self.parameterAsDouble(parameters, self.INPUT_MAX_LINE_LENGTH, context)
         basal_contacts = self.parameterAsSource(parameters, self.INPUT_BASAL_CONTACTS, context)
         geology_source = self.parameterAsSource(parameters, self.INPUT_GEOLOGY, context)
         if geology_source is None:

tests/qgis/test_basal_contacts.py

@@ -1,3 +1,4 @@
+import inspect
 import unittest
 from pathlib import Path
 from unittest.mock import patch
@@ -222,6 +223,20 @@ def test_extraction_error_is_raised(self):
             with self.assertRaisesRegex(RuntimeError, 'bad geology'):
                 self._extract(['A', 'B', 'C'])
 
+    def test_the_list_of_ignored_units_does_not_change(self):
+        ignore_units = ['D']
+        for _ in range(2):
+            extract_basal_contacts(
+                geology=self._geology(),
+                stratigraphic_order=['A', 'B', 'C'],
+                ignore_units=ignore_units,
+                unit_name_field='unitname',
+            )
+        self.assertEqual(ignore_units, ['D'])
+        # the default is not a shared list that grows at each call
+        default = inspect.signature(extract_basal_contacts).parameters['ignore_units'].default
+        self.assertIsNone(default)
+
 
 if __name__ == '__main__':
     unittest.main()