fix issue #194 object attributes always sorted0.15.77

Test for this issue in:

https://bitbucket.org/ruamel/yaml.data/src/default/object/control_base_representer_mapping_sort.yaml

*When this change indeed resolves your problem, please **Close** this issue*.
*(You can do so using the WorkFlow pull-down (close to the top right of this page))*

9 files changed, 103 insertions, 28 deletions

diff --git a/CHANGES b/CHANGES
index 2c8e973..528789a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,10 @@
+[0, 15, 77]: 2018-11-09
+  - setting `yaml.sort_base_mapping_type_on_output = False`, will prevent
+    explicit sorting by keys in the base representer of mappings. Roundtrip
+    already did not do this. Usage only makes real sense for Python 3.6+
+    (feature request by `Sebastian Gerber <https://bitbucket.org/spacemanspiff2007/>`__).
+  - implement Python version check in YAML metadata in ``_test/test_z_data.py``
+
 [0, 15, 76]: 2018-11-01
   - fix issue with empty mapping and sequence loaded as flow-style
     (mapping reported by `Min RK <https://bitbucket.org/minrk/>`__, sequence
diff --git a/README.rst b/README.rst
index 09960a4..a9a645b 100644
--- a/README.rst
+++ b/README.rst
@@ -4,8 +4,8 @@ ruamel.yaml
 
 ``ruamel.yaml`` is a YAML 1.2 loader/dumper package for Python.
 
-:version:       0.15.76
-:updated:       2018-11-01
+:version:       0.15.77
+:updated:       2018-11-09
 :documentation: http://yaml.readthedocs.io
 :repository:    https://bitbucket.org/ruamel/
 :pypi:          https://pypi.org/project/ruamel.yaml/
@@ -54,6 +54,13 @@ ChangeLog
 
 .. should insert NEXT: at the beginning of line for next key (with empty line)
 
+0.15.77 (2018-11-09):
+  - setting `yaml.sort_base_mapping_type_on_output = False`, will prevent
+    explicit sorting by keys in the base representer of mappings. Roundtrip
+    already did not do this. Usage only makes real sense for Python 3.6+
+    (feature request by `Sebastian Gerber <https://bitbucket.org/spacemanspiff2007/>`__).
+  - implement Python version check in YAML metadata in ``_test/test_z_data.py``
+
 0.15.76 (2018-11-01):
   - fix issue with empty mapping and sequence loaded as flow-style
     (mapping reported by `Min RK <https://bitbucket.org/minrk/>`__, sequence
diff --git a/__init__.py b/__init__.py
index 9b28251..bdc47aa 100644
--- a/__init__.py
+++ b/__init__.py
@@ -7,8 +7,8 @@ if False:  # MYPY
 
 _package_data = dict(
     full_package_name='ruamel.yaml',
-    version_info=(0, 15, 76),
-    __version__='0.15.76',
+    version_info=(0, 15, 77),
+    __version__='0.15.77',
     author='Anthon van der Neut',
     author_email='a.van.der.neut@ruamel.eu',
     description='ruamel.yaml is a YAML parser/emitter that supports roundtrip preservation of comments, seq/map flow style, and map key order',  # NOQA
diff --git a/_doc/_static/pypi.svg b/_doc/_static/pypi.svg
index ef9b8ff..b48d281 100644
--- a/_doc/_static/pypi.svg
+++ b/_doc/_static/pypi.svg
@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="86" height="20"><linearGradient id="b" x2="0" y2="100%"><stop offset="0" stop-color="#bbb" stop-opacity=".1"/><stop offset="1" stop-opacity=".1"/></linearGradient><clipPath id="a"><rect width="86" height="20" rx="3" fill="#fff"/></clipPath><g clip-path="url(#a)"><path fill="#555" d="M0 0h33v20H0z"/><path fill="#007ec6" d="M33 0h53v20H33z"/><path fill="url(#b)" d="M0 0h86v20H0z"/></g><g fill="#fff" text-anchor="middle" font-family="DejaVu Sans,Verdana,Geneva,sans-serif" font-size="110"> <text x="175" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="230">pypi</text><text x="175" y="140" transform="scale(.1)" textLength="230">pypi</text><text x="585" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="430">0.15.76</text><text x="585" y="140" transform="scale(.1)" textLength="430">0.15.76</text></g> </svg>
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="86" height="20"><linearGradient id="b" x2="0" y2="100%"><stop offset="0" stop-color="#bbb" stop-opacity=".1"/><stop offset="1" stop-opacity=".1"/></linearGradient><clipPath id="a"><rect width="86" height="20" rx="3" fill="#fff"/></clipPath><g clip-path="url(#a)"><path fill="#555" d="M0 0h33v20H0z"/><path fill="#007ec6" d="M33 0h53v20H33z"/><path fill="url(#b)" d="M0 0h86v20H0z"/></g><g fill="#fff" text-anchor="middle" font-family="DejaVu Sans,Verdana,Geneva,sans-serif" font-size="110"> <text x="175" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="230">pypi</text><text x="175" y="140" transform="scale(.1)" textLength="230">pypi</text><text x="585" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="430">0.15.77</text><text x="585" y="140" transform="scale(.1)" textLength="430">0.15.77</text></g> </svg>
diff --git a/_test/test_z_data.py b/_test/test_z_data.py
index d106a2a..b0464ba 100644
--- a/_test/test_z_data.py
+++ b/_test/test_z_data.py
@@ -2,6 +2,7 @@
 
 from __future__ import print_function, unicode_literals
 
+import sys
 import pytest  # NOQA
 import warnings  # NOQA
 
@@ -83,7 +84,10 @@ def pytest_generate_tests(metafunc):
     paths = sorted(base_path.glob('**/*.yaml'))
     idlist = []
     for path in paths:
-        idlist.append(path.stem)
+        stem = path.stem
+        if stem.startswith('.#'):  # skip emacs temporary file
+            continue
+        idlist.append(stem)
         test_yaml.append([path])
     metafunc.parametrize(['yaml'], test_yaml, ids=idlist, scope='class')
 
@@ -160,6 +164,9 @@ class TestYAMLData(object):
             d = docs[0]
             typ = d.get('type')
             yaml_version = d.get('yaml_version')
+            if 'python' in d:
+                if not check_python_version(d['python']):
+                    pytest.skip("unsupported version")
             idx += 1
         data = output = confirm = python = None
         for doc in docs[idx:]:
@@ -196,3 +203,34 @@ class TestYAMLData(object):
         else:
             print('\nrun type unknown:', typ)
             assert False
+
+
+def check_python_version(match, current=None):
+    """
+    version indication, return True if version matches.
+    match should be something like 3.6+, or [2.7, 3.3] etc. Floats
+    are converted to strings. Single values are made into lists.
+    """
+    if current is None:
+        current = list(sys.version_info[:3])
+    if not isinstance(match, list):
+        match = [match]
+    for m in match:
+        minimal = False
+        if isinstance(m, float):
+            m = str(m)
+        if m.endswith('+'):
+            minimal = True
+            m = m[:-1]
+        # assert m[0].isdigit()
+        # assert m[-1].isdigit()
+        m = [int(x) for x in m.split('.')]
+        current_len = current[:len(m)]
+        # print(m, current, current_len)
+        if minimal:
+            if current_len >= m:
+                return True
+        else:
+            if current_len == m:
+                return True
+    return False
diff --git a/main.py b/main.py
index 35613ef..851ae83 100644
--- a/main.py
+++ b/main.py
@@ -148,6 +148,7 @@ class YAML(object):
         self.sequence_dash_offset = 0
         self.compact_seq_seq = None
         self.compact_seq_map = None
+        self.sort_base_mapping_type_on_output = None  # default: sort
 
         self.top_level_colon_align = None
         self.prefix_colon = None
@@ -289,15 +290,14 @@ class YAML(object):
         # type: () -> Any
         attr = '_' + sys._getframe().f_code.co_name
         if not hasattr(self, attr):
-            setattr(
-                self,
-                attr,
-                self.Representer(
-                    default_style=self.default_style,
-                    default_flow_style=self.default_flow_style,
-                    dumper=self,
-                ),
+            repres = self.Representer(
+                default_style=self.default_style,
+                default_flow_style=self.default_flow_style,
+                dumper=self,
             )
+            if self.sort_base_mapping_type_on_output is not None:
+                repres.sort_base_mapping_type_on_output = self.sort_base_mapping_type_on_output
+            setattr(self, attr, repres)
         return getattr(self, attr)
 
     # separate output resolver?
diff --git a/nodes.py b/nodes.py
index 0a35752..d99e909 100644
--- a/nodes.py
+++ b/nodes.py
@@ -12,14 +12,14 @@ if False:  # MYPY
 class Node(object):
     __slots__ = 'tag', 'value', 'start_mark', 'end_mark', 'comment', 'anchor'
 
-    def __init__(self, tag, value, start_mark, end_mark, comment=None):
-        # type: (Any, Any, Any, Any, Any) -> None
+    def __init__(self, tag, value, start_mark, end_mark, comment=None, anchor=None):
+        # type: (Any, Any, Any, Any, Any, Any) -> None
         self.tag = tag
         self.value = value
         self.start_mark = start_mark
         self.end_mark = end_mark
         self.comment = comment
-        self.anchor = None
+        self.anchor = anchor
 
     def __repr__(self):
         # type: () -> str
@@ -78,14 +78,15 @@ class ScalarNode(Node):
     __slots__ = ('style',)
     id = 'scalar'
 
-    def __init__(self, tag, value, start_mark=None, end_mark=None, style=None, comment=None):
-        # type: (Any, Any, Any, Any, Any, Any) -> None
-        Node.__init__(self, tag, value, start_mark, end_mark, comment=comment)
+    def __init__(self, tag, value, start_mark=None, end_mark=None, style=None, comment=None,
+                 anchor=None):
+        # type: (Any, Any, Any, Any, Any, Any, Any) -> None
+        Node.__init__(self, tag, value, start_mark, end_mark, comment=comment, anchor=anchor)
         self.style = style
 
 
 class CollectionNode(Node):
-    __slots__ = 'flow_style', 'anchor'
+    __slots__ = ('flow_style', )
 
     def __init__(
         self,
diff --git a/representer.py b/representer.py
index e0ac31d..143b7d5 100644
--- a/representer.py
+++ b/representer.py
@@ -65,6 +65,7 @@ class BaseRepresenter(object):
         self.represented_objects = {}  # type: Dict[Any, Any]
         self.object_keeper = []  # type: List[Any]
         self.alias_key = None  # type: Optional[int]
+        self.sort_base_mapping_type_on_output = True
 
     @property
     def serializer(self):
@@ -209,10 +210,11 @@ class BaseRepresenter(object):
         best_style = True
         if hasattr(mapping, 'items'):
             mapping = list(mapping.items())
-            try:
-                mapping = sorted(mapping)
-            except TypeError:
-                pass
+            if self.sort_base_mapping_type_on_output:
+                try:
+                    mapping = sorted(mapping)
+                except TypeError:
+                    pass
         for item_key, item_value in mapping:
             node_key = self.represent_key(item_key)
             node_value = self.represent_data(item_value)
@@ -986,8 +988,7 @@ class RoundTripRepresenter(SafeRepresenter):
                 best_style = False
             value.append((node_key, node_value))
         if flow_style is None:
-            if ((item_count != 0) or bool(merge_list)) \
-               and self.default_flow_style is not None:
+            if ((item_count != 0) or bool(merge_list)) and self.default_flow_style is not None:
                 node.flow_style = self.default_flow_style
             else:
                 node.flow_style = best_style
diff --git a/scalarstring.py b/scalarstring.py
index 03db72d..c7b1a78 100644
--- a/scalarstring.py
+++ b/scalarstring.py
@@ -3,6 +3,7 @@
 from __future__ import print_function, absolute_import, division, unicode_literals
 
 from ruamel.yaml.compat import text_type
+from ruamel.yaml.anchor import Anchor
 
 if False:  # MYPY
     from typing import Text, Any, Dict, List  # NOQA
@@ -20,7 +21,7 @@ __all__ = [
 
 
 class ScalarString(text_type):
-    __slots__ = ()
+    __slots__ = (Anchor.attrib)
 
     def __new__(cls, *args, **kw):
         # type: (Any, Any) -> Any
@@ -30,6 +31,26 @@ class ScalarString(text_type):
         # type: (Any, Any, int) -> Any
         return type(self)((text_type.replace(self, old, new, maxreplace)))
 
+    @property
+    def anchor(self):
+        # type: () -> Any
+        if not hasattr(self, Anchor.attrib):
+            setattr(self, Anchor.attrib, Anchor())
+        return getattr(self, Anchor.attrib)
+
+    def yaml_anchor(self):
+        # type: () -> Any
+        if not hasattr(self, Anchor.attrib):
+            return None
+        if not self.anchor.always_dump:
+            return None
+        return self.anchor
+
+    def yaml_set_anchor(self, value, always_dump=False):
+        # type: (Any, bool) -> None
+        self.anchor.value = value
+        self.anchor.always_dump = always_dump
+
 
 class LiteralScalarString(ScalarString):
     __slots__ = 'comment'  # the comment after the | on the first line