Switched the expansion algorithm to resolve mixins in-place (little known feature) and also changed the parser to skip all non-preset sections. Tests are included for these two behaviors.

Author: Rostepher

utils/build_swift/presets.py

@@ -13,7 +13,6 @@
 
 
 from collections import namedtuple
-from copy import copy
 
 try:
     # Python 3
@@ -37,7 +36,9 @@
 
 # -----------------------------------------------------------------------------
 
-_RawPreset = namedtuple('_RawPreset', ['name', 'mixins', 'args'])
+_Mixin = namedtuple('_Mixin', ['name'])
+_Argument = namedtuple('_Argument', ['name', 'value'])
+_RawPreset = namedtuple('_RawPreset', ['name', 'options'])
 
 
 def _interpolate_string(string, values):
@@ -128,25 +129,29 @@ def _parse_raw_preset(self, section):
         except configparser.InterpolationMissingOptionError as e:
             raise MissingOptionError(e)
 
-        args, mixins = [], []
+        args = []
         for (name, value) in section_items:
             # Ignore the '--' separator, it's no longer necessary
             if name == 'dash-dash':
                 continue
 
             # Parse out mixin names
             if name == 'mixin-preset':
-                mixins = list(map(lambda name: name.strip(),
-                                  value.strip().splitlines()))
+                lines = value.strip().splitlines()
+                args += [_Mixin(name.strip()) for name in lines]
                 continue
 
             name = '--' + name  # Format as an option name
-            args.append((name, value))
+            args.append(_Argument(name, value))
 
-        return _RawPreset(preset_name, mixins, args)
+        return _RawPreset(preset_name, args)
 
     def _parse_raw_presets(self):
         for section in self._parser.sections():
+            # Skip all non-preset sections
+            if not section.startswith(PresetParser._PRESET_PREFIX):
+                continue
+
             raw_preset = self._parse_raw_preset(section)
             self._presets[raw_preset.name] = raw_preset
 
@@ -203,11 +208,14 @@ def _resolve_preset_mixins(self, raw_preset):
         assert isinstance(raw_preset, _RawPreset)
 
         # Expand mixin arguments
-        args = copy(raw_preset.args)
-        for mixin_name in raw_preset.mixins:
-            mixin = self._get_preset(mixin_name)
-
-            args += mixin.args
+        args = []
+        for option in raw_preset.options:
+            if isinstance(option, _Mixin):
+                args += self._get_preset(option.name).args
+            elif isinstance(option, _Argument):
+                args.append((option.name, option.value))
+            else:
+                raise ValueError('invalid argument type: {}', option.__class__)
 
         return Preset(raw_preset.name, args)
 

utils/build_swift/tests/test_presets.py

@@ -70,6 +70,24 @@
 ios
 """
 
+IGNORED_SECTION = """
+[section_name]
+
+random-options=1
+"""
+
+MIXIN_ORDER_PRESETS = """
+[preset: test_mixin]
+first-opt=0
+second-opt=1
+
+
+[preset: test]
+first-opt=1
+mixin-preset=test_mixin
+second-opt=2
+"""
+
 
 # -----------------------------------------------------------------------------
 
@@ -154,6 +172,31 @@ def test_read_string(self):
             (u'--install-symroot', u'/tmp')
         ])
 
+    def test_parser_ignores_non_preset_sections(self):
+        parser = PresetParser()
+
+        parser.read_string(IGNORED_SECTION)
+        self.assertEqual(len(parser._presets), 0)
+
+    def test_mixin_expansion_preserves_argument_order(self):
+        """Mixins should be expanded in-place.
+        """
+
+        parser = PresetParser()
+
+        parser.read_string(MIXIN_ORDER_PRESETS)
+
+        preset = parser.get_preset('test')
+        self.assertListEqual(preset.format_args(), [
+            '--first-opt=1',
+
+            # Mixin arguments
+            '--first-opt=0',
+            '--second-opt=1',
+
+            '--second-opt=2',
+        ])
+
     def test_duplicate_option_error(self):
         parser = PresetParser()