Allow files not to be created during an update

CHANGES.rst

@@ -10,6 +10,8 @@ Version 2.2, 2015-??-??
 - Improved default README.rst, issue #51
 - Use tests/conftest.py instead of tests/__init__.py, issue #52
 - Use setuptools_scm for versioning, issue #43
+- Require setuptools>=9.0, issue #56
+- Do not create skeleton.py during an update, issue #55
 
 .. note::
 

pyscaffold/structure.py

@@ -19,6 +19,17 @@
 __license__ = "new BSD"
 
 
+class FileOp(object):
+    """
+    Namespace for file operations during an update
+
+    NO_OVERWRITE: Do not overwrite an existing file during update
+    NO_CREATE: Do not create the file during an update
+    """
+    NO_OVERWRITE = 0
+    NO_CREATE = 1
+
+
 def set_default_args(args):
     """
     Set default arguments for some parameters
@@ -114,26 +125,25 @@ def make_structure(args):
     if args.tox:
         proj_dir["tox.ini"] = templates.tox(args)
     if args.update and not args.force:  # Do not overwrite following files
-        safe = {args.project: {
-            ".gitignore": None,
-            ".gitattributes": None,
-            "setup.cfg": None,
-            "README.rst": None,
-            "CHANGES.rst": None,
-            "LICENSE.txt": None,
-            "AUTHORS.rst": None,
-            "requirements.txt": None,
-            ".travis.yml": None,
-            ".coveragerc": None,
-            ".pre-commit-config.yaml": None,
-            "tox.ini": None,
-            args.package: {"skeleton.py": None},
-            "tests": {"conftest.py": None,
-                      "travis_install.sh": None},
-            "docs": {"index.rst": None}
+        rules = {args.project: {
+            ".gitignore": FileOp.NO_OVERWRITE,
+            ".gitattributes": FileOp.NO_OVERWRITE,
+            "setup.cfg": FileOp.NO_OVERWRITE,
+            "README.rst": FileOp.NO_OVERWRITE,
+            "CHANGES.rst": FileOp.NO_OVERWRITE,
+            "LICENSE.txt": FileOp.NO_OVERWRITE,
+            "AUTHORS.rst": FileOp.NO_OVERWRITE,
+            "requirements.txt": FileOp.NO_OVERWRITE,
+            ".travis.yml": FileOp.NO_OVERWRITE,
+            ".coveragerc": FileOp.NO_OVERWRITE,
+            ".pre-commit-config.yaml": FileOp.NO_OVERWRITE,
+            "tox.ini": FileOp.NO_OVERWRITE,
+            args.package: {"skeleton.py": FileOp.NO_CREATE},
+            "tests": {"conftest.py": FileOp.NO_OVERWRITE,
+                      "travis_install.sh": FileOp.NO_OVERWRITE},
+            "docs": {"index.rst": FileOp.NO_OVERWRITE}
         }}
-        safe = check_files_exist(safe)
-        struct = remove_from_struct(struct, safe)
+        struct = apply_update_rules(rules, struct)
     struct = add_namespace(args, struct)
 
     return struct
@@ -186,6 +196,11 @@ def create_django_proj(args):
 
 
 def create_cookiecutter(args):
+    """
+    Create a cookie cutter template
+
+    :param args: command line parameters as :obj:`argparse.Namespace`
+    """
     try:
         from cookiecutter.main import cookiecutter
     except:
@@ -206,50 +221,26 @@ def create_cookiecutter(args):
     args.force = True
 
 
-def check_files_exist(struct, prefix=None):
+def apply_update_rules(rules, struct, prefix=None):
     """
-    Checks which files exist in a directory structure
+    Apply update rules using :obj:`~.FileOp` to a directory structure
 
+    :param rules: directory structure as dictionary of dictionaries with
+        :obj:`~.FileOp` keys. The structure will be modified.
     :param struct: directory structure as dictionary of dictionaries
     :param prefix: prefix path for the structure
     :return: returns a dictionary of dictionaries where keys representing
         files exists in the filesystem.
     """
-    result = dict()
     if prefix is None:
         prefix = os.getcwd()
-    for name, content in struct.items():
-        if isinstance(content, dict):
-            result[name] = check_files_exist(struct[name],
-                                             prefix=join_path(prefix, name))
-            if not result[name]:  # dict is empty
-                del result[name]
-        else:
-            if os.path.isfile(join_path(prefix, name)):
-                result[name] = content
-    return result
-
-
-def remove_from_struct(orig_struct, del_struct):
-    """
-    Removes files existing in `del_struct` from structure `orig_struct`
-
-    :param orig_struct: directory structure as dictionary of dictionaries
-    :param del_struct: directory structure as dictionary of dictionaries
-    :return: directory structure as dictionary of dictionaries
-    """
-    result = dict()
-    for k, v in orig_struct.items():
+    for k, v in rules.items():
         if isinstance(v, dict):
-            if k in del_struct:
-                result[k] = remove_from_struct(orig_struct[k], del_struct[k])
-                if not result[k]:  # dict is empty
-                    del result[k]
-            else:
-                result[k] = copy.deepcopy(orig_struct[k])
+            apply_update_rules(v, struct[k], join_path(prefix, k))
         else:
-            if k in del_struct:
-                continue
-            else:
-                result[k] = orig_struct[k]
-    return result
+            path = join_path(prefix, k)
+            if v == FileOp.NO_OVERWRITE and os.path.exists(path):
+                struct.pop(k, None)
+            elif v == FileOp.NO_CREATE:
+                struct.pop(k, None)
+    return struct

tests/test_structure.py

@@ -104,31 +104,31 @@ def test_make_structure_with_tox():
     assert isinstance(struct["project"]["tox.ini"], six.string_types)
 
 
-def test_check_files_exist(tmpdir):  # noqa
-    struct = {"a": "a", "b": "b", "c": {"a": "a", "b": "b"}, "d": {"a": "a"}}
-    dir_struct = {"a": "a", "c": {"b": "b"}}
+def test_apply_update_rules(tmpdir):  # noqa
+    NO_OVERWRITE = structure.FileOp.NO_OVERWRITE
+    NO_CREATE = structure.FileOp.NO_CREATE
+    rules = {"a": NO_OVERWRITE,
+             "c": {"b": NO_OVERWRITE},
+             "d": {"a": NO_OVERWRITE,
+                   "b": NO_CREATE,
+                   "c": NO_CREATE,
+                   "d": NO_OVERWRITE},
+             "e": NO_CREATE}
+    struct = {"a": "a",
+              "b": "b",
+              "c": {"a": "a",
+                    "b": "b"},
+              "d": {"a": "a",
+                    "b": "b"},
+              "e": "e"}
+    dir_struct = {"a": "a",
+                  "c": {"b": "b"}}
+    exp_struct = {"b": "b",
+                  "c": {"a": "a"},
+                  "d": {"a": "a"}}
     structure.create_structure(dir_struct)
-    res = structure.check_files_exist(struct)
-    assert res == dir_struct
-
-
-def test_remove_from_struct():
-    orig_struct = {"a": 1, "b": 2, "c": 3}
-    del_struct = {"a": 1}
-    res = structure.remove_from_struct(orig_struct, del_struct)
-    assert res == {"b": 2, "c": 3}
-    orig_struct = {"a": 1, "b": 2, "c": {"a": 1}}
-    del_struct = {"a": 1}
-    res = structure.remove_from_struct(orig_struct, del_struct)
-    assert res == {"b": 2, "c": {"a": 1}}
-    orig_struct = {"a": 1, "b": 2, "c": {"a": 1}}
-    del_struct = {"c": {"a": 1}}
-    res = structure.remove_from_struct(orig_struct, del_struct)
-    assert res == {"a": 1, "b": 2}
-    orig_struct = {"a": 1, "b": 2, "c": {"a": 1, "b": 2}}
-    del_struct = {"a": 1, "c": {"a": 1}}
-    res = structure.remove_from_struct(orig_struct, del_struct)
-    assert res == {"b": 2, "c": {"b": 2}}
+    res_struct = structure.apply_update_rules(rules, struct)
+    assert res_struct == exp_struct
 
 
 def test_add_namespace():