Fix a bug in cmake args parsing overrides (See scikit-build#342)

skbuild/cmaker.py

@@ -61,7 +61,7 @@ def has_cmake_cache_arg(cmake_args, arg_name, arg_value=None):
     """Return True if ``-D<arg_name>:TYPE=<arg_value>`` is found
     in ``cmake_args``. If ``arg_value`` is None, return True only if
     ``-D<arg_name>:`` is found in the list."""
-    for arg in cmake_args:
+    for arg in reverse(cmake_args):
         if arg.startswith("-D%s:" % arg_name):
             if arg_value is None:
                 return True

tests/test_cmaker.py

@@ -47,6 +47,16 @@ def test_has_cmake_cache_arg():
     assert has_cmake_cache_arg(cmake_args, "CLIMBING", None)
     assert has_cmake_cache_arg(cmake_args, "CLIMBING", "ON")
 
+    override = ['-DOTHER:STRING=C','-DOVERRIDE:STRING=A', '-DOVERRIDE:STRING=B']
+    assert has_cmake_cache_arg(override, 'OVERRIDE')
+    assert has_cmake_cache_arg(override, 'OVERRIDE', 'B')
+    assert not has_cmake_cache_arg(override, 'OVERRIDE', 'A')
+    # ensure overriding doesn't magically have side effects. 
+    assert has_cmake_cache_arg(override, 'OTHER')
+    assert has_cmake_cache_arg(override, 'OTHER', 'C')
+    assert not has_cmake_cache_arg(override, 'OTHER', 'A')
+    assert not has_cmake_cache_arg(override, 'OTHER', 'B')
+
 
 def test_make_without_build_dir_fails():
     src_dir = _tmpdir('test_make_without_build_dir_fails')