templater: separate function to create templater from map file (API)

New frommapfile() function will make it clear when template aliases will be
loaded. They should be applied to command arguments and templates in hgrc,
but not to map files. Otherwise, our stock styles and web templates
(i.e map-file templates) could be modified unintentionally.

Future patches will add "aliases" argument to __init__(), but not to
frommapfile().

mercurial/cmdutil.py

@@ -1478,6 +1478,7 b' class changeset_templater(changeset_prin'
     def __init__(self, ui, repo, matchfn, diffopts, tmpl, mapfile, buffered):
         changeset_printer.__init__(self, ui, repo, matchfn, diffopts, buffered)
         formatnode = ui.debugflag and (lambda x: x) or (lambda x: x[:12])
+        filters = {'formatnode': formatnode}
         defaulttempl = {
             'parent': '{rev}:{node|formatnode} ',
             'manifest': '{rev}:{node|formatnode}',
@@ -1486,8 +1487,12 b' class changeset_templater(changeset_prin'
             }
         # filecopy is preserved for compatibility reasons
         defaulttempl['filecopy'] = defaulttempl['file_copy']
-        self.t = templater.templater(mapfile, {'formatnode': formatnode},
+        assert not (tmpl and mapfile)
+        if mapfile:
+            self.t = templater.templater.frommapfile(mapfile, filters=filters,
                                      cache=defaulttempl)
+        else:
+            self.t = templater.templater(filters=filters, cache=defaulttempl)
         if tmpl:
             self.t.cache['changeset'] = tmpl
 

mercurial/commands.py

@@ -2770,7 +2770,7 b' def debuginstall(ui, **opts):'
             # template found, check if it is working
             err = None
             try:
-                templater.templater(m)
+                templater.templater.frommapfile(m)
             except Exception as inst:
                 err = inst
                 p = None
@@ -3681,7 +3681,7 b' def debugtemplate(ui, repo, tmpl, **opts'
     mapfile = None
     if revs is None:
         k = 'debugtemplate'
-        t = templater.templater(mapfile)
+        t = templater.templater()
         t.cache[k] = tmpl
         ui.write(templater.stringify(t(k, **props)))
     else:

mercurial/filemerge.py

@@ -526,7 +526,7 b' def _formatlabels(repo, fcd, fco, fca, l'
 
     ui = repo.ui
     template = ui.config('ui', 'mergemarkertemplate', _defaultconflictmarker)
-    tmpl = templater.templater(None, cache={'conflictmarker': template})
+    tmpl = templater.templater(cache={'conflictmarker': template})
 
     pad = max(len(l) for l in labels)
 

mercurial/formatter.py

@@ -190,7 +190,10 b' def lookuptemplate(ui, topic, tmpl):'
 
 def gettemplater(ui, topic, spec):
     tmpl, mapfile = lookuptemplate(ui, topic, spec)
-    t = templater.templater(mapfile, {})
+    assert not (tmpl and mapfile)
+    if mapfile:
+        return templater.templater.frommapfile(mapfile)
+    t = templater.templater()
     if tmpl:
         t.cache[topic] = tmpl
     return t

mercurial/hgweb/hgweb_mod.py

@@ -188,9 +188,8 b' class requestcontext(object):'
 
         # create the templater
 
-        tmpl = templater.templater(mapfile,
-                                   filters={'websub': websubfilter},
-                                   defaults={'url': req.url,
+        defaults = {
+            'url': req.url,
                                              'logourl': logourl,
                                              'logoimg': logoimg,
                                              'staticurl': staticurl,
@@ -201,7 +200,10 b' class requestcontext(object):'
                                              'sessionvars': sessionvars,
                                              'pathdef': makebreadcrumb(req.url),
                                              'style': style,
-                                            })
+        }
+        tmpl = templater.templater.frommapfile(mapfile,
+                                               filters={'websub': websubfilter},
+                                               defaults=defaults)
         return tmpl
 
 

mercurial/hgweb/hgwebdir_mod.py

@@ -491,8 +491,8 b' class hgwebdir(object):'
         if not staticurl.endswith('/'):
             staticurl += '/'
 
-        tmpl = templater.templater(mapfile,
-                                   defaults={"encoding": encoding.encoding,
+        defaults = {
+            "encoding": encoding.encoding,
                                              "motd": motd,
                                              "url": url,
                                              "logourl": logourl,
@@ -500,7 +500,8 b' class hgwebdir(object):'
                                              "staticurl": staticurl,
                                              "sessionvars": sessionvars,
                                              "style": style,
-                                             })
+        }
+        tmpl = templater.templater.frommapfile(mapfile, defaults=defaults)
         return tmpl
 
     def updatereqenv(self, env):

mercurial/templater.py

@@ -1016,10 +1016,9 b' class TemplateNotFound(error.Abort):'
 
 class templater(object):
 
-    def __init__(self, mapfile, filters=None, defaults=None, cache=None,
+    def __init__(self, filters=None, defaults=None, cache=None,
                  minchunk=1024, maxchunk=65536):
         '''set up template engine.
-        mapfile is name of file to read map definitions from.
         filters is dict of functions. each transforms a value into another.
         defaults is dict of default map definitions.'''
         if filters is None:
@@ -1036,11 +1035,15 b' class templater(object):'
         self.minchunk, self.maxchunk = minchunk, maxchunk
         self.ecache = {}
 
-        if not mapfile:
-            return
+    @classmethod
+    def frommapfile(cls, mapfile, filters=None, defaults=None, cache=None,
+                    minchunk=1024, maxchunk=65536):
+        """Create templater from the specified map file"""
+        t = cls(filters, defaults, cache, minchunk, maxchunk)
         cache, tmap = _readmapfile(mapfile)
-        self.cache.update(cache)
-        self.map = tmap
+        t.cache.update(cache)
+        t.map = tmap
+        return t
 
     def __contains__(self, key):
         return key in self.cache or key in self.map