registrar: raise a programming error on duplicated registering

Previous, registering different object with the same name would silently
overwrite the first value with the second one. We now detect the situation and
raise an error. No extension in test or core had the issues.

mercurial/registrar.py

@@ -1,249 +1,254 b''
 # registrar.py - utilities to register function for specific purpose
 #
 #  Copyright FUJIWARA Katsunori <[e-mail]> and others
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 from . import (
+    error,
     pycompat,
     util,
 )
 
 class _funcregistrarbase(object):
     """Base of decorator to register a function for specific purpose
 
     This decorator stores decorated functions into own dict 'table'.
 
     The least derived class can be defined by overriding 'formatdoc',
     for example::
 
         class keyword(_funcregistrarbase):
             _docformat = ":%s: %s"
 
     This should be used as below:
 
         keyword = registrar.keyword()
 
         @keyword('bar')
         def barfunc(*args, **kwargs):
             '''Explanation of bar keyword ....
             '''
             pass
 
     In this case:
 
     - 'barfunc' is stored as 'bar' in '_table' of an instance 'keyword' above
     - 'barfunc.__doc__' becomes ":bar: Explanation of bar keyword"
     """
     def __init__(self, table=None):
         if table is None:
             self._table = {}
         else:
             self._table = table
 
     def __call__(self, decl, *args, **kwargs):
         return lambda func: self._doregister(func, decl, *args, **kwargs)
 
     def _doregister(self, func, decl, *args, **kwargs):
         name = self._getname(decl)
 
+        if name in self._table:
+            msg = 'duplicate registration for name: "%s"' % name
+            raise error.ProgrammingError(msg)
+
         if func.__doc__ and not util.safehasattr(func, '_origdoc'):
             doc = func.__doc__.strip()
             func._origdoc = doc
             func.__doc__ = self._formatdoc(decl, doc)
 
         self._table[name] = func
         self._extrasetup(name, func, *args, **kwargs)
 
         return func
 
     def _parsefuncdecl(self, decl):
         """Parse function declaration and return the name of function in it
         """
         i = decl.find('(')
         if i >= 0:
             return decl[:i]
         else:
             return decl
 
     def _getname(self, decl):
         """Return the name of the registered function from decl
 
         Derived class should override this, if it allows more
         descriptive 'decl' string than just a name.
         """
         return decl
 
     _docformat = None
 
     def _formatdoc(self, decl, doc):
         """Return formatted document of the registered function for help
 
         'doc' is '__doc__.strip()' of the registered function.
         """
         return self._docformat % (decl, doc)
 
     def _extrasetup(self, name, func):
         """Execute exra setup for registered function, if needed
         """
         pass
 
 class revsetpredicate(_funcregistrarbase):
     """Decorator to register revset predicate
 
     Usage::
 
         revsetpredicate = registrar.revsetpredicate()
 
         @revsetpredicate('mypredicate(arg1, arg2[, arg3])')
         def mypredicatefunc(repo, subset, x):
             '''Explanation of this revset predicate ....
             '''
             pass
 
     The first string argument is used also in online help.
 
     Optional argument 'safe' indicates whether a predicate is safe for
     DoS attack (False by default).
 
     Optional argument 'takeorder' indicates whether a predicate function
     takes ordering policy as the last argument.
 
     'revsetpredicate' instance in example above can be used to
     decorate multiple functions.
 
     Decorated functions are registered automatically at loading
     extension, if an instance named as 'revsetpredicate' is used for
     decorating in extension.
 
     Otherwise, explicit 'revset.loadpredicate()' is needed.
     """
     _getname = _funcregistrarbase._parsefuncdecl
     _docformat = pycompat.sysstr("``%s``\n    %s")
 
     def _extrasetup(self, name, func, safe=False, takeorder=False):
         func._safe = safe
         func._takeorder = takeorder
 
 class filesetpredicate(_funcregistrarbase):
     """Decorator to register fileset predicate
 
     Usage::
 
         filesetpredicate = registrar.filesetpredicate()
 
         @filesetpredicate('mypredicate()')
         def mypredicatefunc(mctx, x):
             '''Explanation of this fileset predicate ....
             '''
             pass
 
     The first string argument is used also in online help.
 
     Optional argument 'callstatus' indicates whether a predicate
      implies 'matchctx.status()' at runtime or not (False, by
      default).
 
     Optional argument 'callexisting' indicates whether a predicate
     implies 'matchctx.existing()' at runtime or not (False, by
     default).
 
     'filesetpredicate' instance in example above can be used to
     decorate multiple functions.
 
     Decorated functions are registered automatically at loading
     extension, if an instance named as 'filesetpredicate' is used for
     decorating in extension.
 
     Otherwise, explicit 'fileset.loadpredicate()' is needed.
     """
     _getname = _funcregistrarbase._parsefuncdecl
     _docformat = pycompat.sysstr("``%s``\n    %s")
 
     def _extrasetup(self, name, func, callstatus=False, callexisting=False):
         func._callstatus = callstatus
         func._callexisting = callexisting
 
 class _templateregistrarbase(_funcregistrarbase):
     """Base of decorator to register functions as template specific one
     """
     _docformat = pycompat.sysstr(":%s: %s")
 
 class templatekeyword(_templateregistrarbase):
     """Decorator to register template keyword
 
     Usage::
 
         templatekeyword = registrar.templatekeyword()
 
         @templatekeyword('mykeyword')
         def mykeywordfunc(repo, ctx, templ, cache, revcache, **args):
             '''Explanation of this template keyword ....
             '''
             pass
 
     The first string argument is used also in online help.
 
     'templatekeyword' instance in example above can be used to
     decorate multiple functions.
 
     Decorated functions are registered automatically at loading
     extension, if an instance named as 'templatekeyword' is used for
     decorating in extension.
 
     Otherwise, explicit 'templatekw.loadkeyword()' is needed.
     """
 
 class templatefilter(_templateregistrarbase):
     """Decorator to register template filer
 
     Usage::
 
         templatefilter = registrar.templatefilter()
 
         @templatefilter('myfilter')
         def myfilterfunc(text):
             '''Explanation of this template filter ....
             '''
             pass
 
     The first string argument is used also in online help.
 
     'templatefilter' instance in example above can be used to
     decorate multiple functions.
 
     Decorated functions are registered automatically at loading
     extension, if an instance named as 'templatefilter' is used for
     decorating in extension.
 
     Otherwise, explicit 'templatefilters.loadkeyword()' is needed.
     """
 
 class templatefunc(_templateregistrarbase):
     """Decorator to register template function
 
     Usage::
 
         templatefunc = registrar.templatefunc()
 
         @templatefunc('myfunc(arg1, arg2[, arg3])')
         def myfuncfunc(context, mapping, args):
             '''Explanation of this template function ....
             '''
             pass
 
     The first string argument is used also in online help.
 
     'templatefunc' instance in example above can be used to
     decorate multiple functions.
 
     Decorated functions are registered automatically at loading
     extension, if an instance named as 'templatefunc' is used for
     decorating in extension.
 
     Otherwise, explicit 'templater.loadfunction()' is needed.
     """
     _getname = _funcregistrarbase._parsefuncdecl