Nail down types.

src/allmydata/dirnode.py

@@ -74,6 +74,13 @@ ADD_FILE = ActionType(
     u"Add a new file as a child of a directory.",
 )
 
+
+class _OnlyFiles(object):
+    """Marker for replacement option of only replacing files."""
+
+ONLY_FILES = _OnlyFiles()
+
+
 def update_metadata(metadata, new_metadata, now):
     """Updates 'metadata' in-place with the information in 'new_metadata'.
 
@@ -179,7 +186,7 @@ class Adder(object):
         if entries is None:
             entries = {}
         precondition(isinstance(entries, dict), entries)
-        precondition(overwrite in (True, False, "only-files"), overwrite)
+        precondition(overwrite in (True, False, ONLY_FILES), overwrite)
         # keys of 'entries' may not be normalized.
         self.entries = entries
         self.overwrite = overwrite
@@ -205,7 +212,7 @@ class Adder(object):
                 if not self.overwrite:
                     raise ExistingChildError("child %s already exists" % quote_output(name, encoding='utf-8'))
 
-                if self.overwrite == "only-files" and IDirectoryNode.providedBy(children[name][0]):
+                if self.overwrite == ONLY_FILES and IDirectoryNode.providedBy(children[name][0]):
                     raise ExistingChildError("child %s already exists as a directory" % quote_output(name, encoding='utf-8'))
                 metadata = children[name][1].copy()
 
@@ -701,7 +708,7 @@ class DirectoryNode(object):
         'new_child_namex' and 'current_child_namex' need not be normalized.
 
         The overwrite parameter may be True (overwrite any existing child),
-        False (error if the new child link already exists), or "only-files"
+        False (error if the new child link already exists), or ONLY_FILES
         (error if the new child link exists and points to a directory).
         """
         if self.is_readonly() or new_parent.is_readonly():

src/allmydata/test/test_dirnode.py

@@ -1978,12 +1978,12 @@ class Adder(GridTestMixin, unittest.TestCase, testutil.ShouldFailMixin):
                                 overwrite=False))
             d.addCallback(lambda res:
                 root_node.set_node(u'file1', filenode,
-                                   overwrite="only-files"))
+                                   overwrite=dirnode.ONLY_FILES))
             d.addCallback(lambda res:
                 self.shouldFail(ExistingChildError, "set_node",
                                 "child 'dir1' already exists",
                                 root_node.set_node, u'dir1', filenode,
-                                overwrite="only-files"))
+                                overwrite=dirnode.ONLY_FILES))
             return d
 
         d.addCallback(_test_adder)

src/allmydata/test/web/test_util.py

@@ -12,17 +12,18 @@ if PY2:
 
 from twisted.trial import unittest
 from allmydata.web import status, common
+from allmydata.dirnode import ONLY_FILES
 from ..common import ShouldFailMixin
 from .. import common_util as testutil
 
 class Util(ShouldFailMixin, testutil.ReallyEqualMixin, unittest.TestCase):
 
     def test_parse_replace_arg(self):
-        self.failUnlessReallyEqual(common.parse_replace_arg("true"), True)
-        self.failUnlessReallyEqual(common.parse_replace_arg("false"), False)
-        self.failUnlessReallyEqual(common.parse_replace_arg("only-files"),
-                                   "only-files")
-        self.failUnlessRaises(common.WebError, common.parse_replace_arg, "only_fles")
+        self.failUnlessReallyEqual(common.parse_replace_arg(b"true"), True)
+        self.failUnlessReallyEqual(common.parse_replace_arg(b"false"), False)
+        self.failUnlessReallyEqual(common.parse_replace_arg(b"only-files"),
+                                   ONLY_FILES)
+        self.failUnlessRaises(common.WebError, common.parse_replace_arg, b"only_fles")
 
     def test_abbreviate_time(self):
         self.failUnlessReallyEqual(common.abbreviate_time(None), "")

src/allmydata/web/common.py

@@ -2,7 +2,7 @@ from past.builtins import unicode
 from six import ensure_text, ensure_str
 
 try:
-    from typing import Optional
+    from typing import Optional, Union
 except ImportError:
     pass
 
@@ -56,6 +56,7 @@ from twisted.web.resource import (
     IResource,
 )
 
+from allmydata.dirnode import ONLY_FILES, _OnlyFiles
 from allmydata import blacklist
 from allmydata.interfaces import (
     EmptyPathnameComponentError,
@@ -105,17 +106,17 @@ def get_filenode_metadata(filenode):
         metadata['size'] = size
     return metadata
 
-def boolean_of_arg(arg):
-    # TODO: ""
-    arg = ensure_text(arg)
-    if arg.lower() not in ("true", "t", "1", "false", "f", "0", "on", "off"):
+def boolean_of_arg(arg):  # type: (bytes) -> bool
+    assert isinstance(arg, bytes)
+    if arg.lower() not in (b"true", b"t", b"1", b"false", b"f", b"0", b"on", b"off"):
         raise WebError("invalid boolean argument: %r" % (arg,), http.BAD_REQUEST)
-    return arg.lower() in ("true", "t", "1", "on")
+    return arg.lower() in (b"true", b"t", b"1", b"on")
 
-def parse_replace_arg(replace):
-    replace = ensure_text(replace)
-    if replace.lower() == "only-files":
-        return replace
+
+def parse_replace_arg(replace):  # type: (bytes) -> Union[bool,_OnlyFiles]
+    assert isinstance(replace, bytes)
+    if replace.lower() == b"only-files":
+        return ONLY_FILES
     try:
         return boolean_of_arg(replace)
     except WebError: