no error on zero length line

Removes the error for projecting to a zero length line with no clamping. Instead it behaves just like a clamped line.

Author: MyreMylar

docs/reST/ref/geometry.rst

@@ -762,7 +762,7 @@
 
             Example of what the clamp argument changes. If it is `True`, the point is bounded between the line segment ends.
 
-            WARNING: This method has to have some length or the clamp parameter must be true for it to work and not throw a `ValueError`
+            WARNING:  If the line has no length (i.e. the start and end points are the same) then the returned point of this function will be the same point as both ends of the line.
 
          .. versionadded:: 2.5.6
 

src_c/line.c

@@ -227,18 +227,13 @@ _line_project_helper(pgLineBase *line, double *point, int clamp)
     double squared_line_length =
         line_vector[0] * line_vector[0] + line_vector[1] * line_vector[1];
 
-    if (squared_line_length == 0.0 && clamp) {
+    if (squared_line_length == 0.0) {
         double projected_point[2];
         projected_point[0] = line->ax;
         projected_point[1] = line->ay;
         return pg_tuple_couple_from_values_double(projected_point[0],
                                                   projected_point[1]);
     }
-    else if (squared_line_length == 0.0) {
-        return RAISE(PyExc_ValueError,
-                     "The Line has to have some length or this method has to "
-                     "be clamped to work");
-    }
 
     // this is a vector that goes from the start of the line to the point we
     // are projecting onto the line

test/geometry_test.py

@@ -2231,9 +2231,8 @@ def test_meth_project(self):
         self.assertEqual(math.ceil(projected_point[0]), 0)
         self.assertEqual(math.ceil(projected_point[1]), 0)
 
-        # testing if the method fails when it should
-        with self.assertRaises(ValueError):
-            bad_line.project(test_bad_line_point)
+        projected_point = bad_line.project(test_bad_line_point)
+        self.assertEqual(math.ceil(projected_point[0]), 0)
 
     def test__str__(self):
         """Checks whether the __str__ method works correctly."""