posix: do not use fstat in isowner

The fstat function was undefined, but never used since a stat object
was always passed in the optional st argument. Passing st is now
mandatory.

This bug crept in when util was split up into posix and windows
modules. The fstat function is still defined in util, but importing it
into posix would create an import cycle which seems unnecessary.

mercurial/posix.py

@@ -139,13 +139,8 b' def explain_exit(code):'
         return _("stopped by signal %d") % val, val
     raise ValueError(_("invalid exit code"))
 
-def isowner(fp, st=None):
-    """Return True if the file object f belongs to the current user.
-
-    The return value of a util.fstat(f) may be passed as the st argument.
-    """
-    if st is None:
-        st = fstat(fp)
+def isowner(st):
+    """Return True if the stat object st is from the current user."""
     return st.st_uid == os.getuid()
 
 def find_exe(command):

mercurial/ui.py

@@ -40,7 +40,7 b' class ui(object):'
 
     def _is_trusted(self, fp, f):
         st = util.fstat(fp)
-        if util.isowner(fp, st):
+        if util.isowner(st):
             return True
 
         tusers, tgroups = self._trustusers, self._trustgroups

mercurial/windows.py

@@ -164,7 +164,7 b' def explain_exit(code):'
 
 # if you change this stub into a real check, please try to implement the
 # username and groupname functions above, too.
-def isowner(fp, st=None):
+def isowner(st):
     return True
 
 def find_exe(command):

tests/test-trusted.py

@@ -44,7 +44,7 b" def testui(user='foo', group='bar', tuse"
         return group
     util.groupname = groupname
 
-    def isowner(fp, st=None):
+    def isowner(st):
         return user == cuser
     util.isowner = isowner