D5959: templates: adding a config() function for template customization.

[rdamazio (Rodrigo Damazio Bovendorp)]

rdamazio created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  This allows templates to be written such that users can customize them easily,
  or that they can be customized based on other configuration of the system.  For
  enterprise deployments, we often have complex template aliases, and right now
  the only way individual users can customize those is by replacing the whole
  template alias (which means they won't get company-wide updates to it anymore,
  plus most users don't want to have to get a complex template right).
  With this change, they can just set a config option which feeds into our
  templates for common changes (e.g. whether to limit commit descriptions to the
  width of their terminal or not).
  
  To work around the issue of having to register the config options, I declared
  a dedicated section [templateconfig] for these options to be dynamically
  declared. They can still reference any other config option that's registered
  elsewhere.
  
  I only did string, bool and int at this time - list and date would add other
  complications with parsing the default so I'll leave that as an exercise to
  the reader :)

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D5959

AFFECTED FILES
  mercurial/configitems.py
  mercurial/templatefuncs.py
  tests/test-template-functions.t

CHANGE DETAILS

diff --git a/tests/test-template-functions.t b/tests/test-template-functions.t
--- a/tests/test-template-functions.t
+++ b/tests/test-template-functions.t
@@ -1549,4 +1549,31 @@
   $ HGENCODING=utf-8 hg debugtemplate "{pad('`cat utf-8`', 2, '-')}\n"
   \xc3\xa9- (esc)
 
+read config options:
+
+  $ hg log -T "{config('templateconfig', 'knob', 'foo')}\n"
+  foo
+  $ hg log -T "{config('templateconfig', 'knob', 'foo')}\n" \
+  > --config templateconfig.knob=bar
+  bar
+  $ hg log -T "{configbool('templateconfig', 'knob', True)}\n"
+  True
+  $ hg log -T "{configbool('templateconfig', 'knob', True)}\n" \
+  > --config templateconfig.knob=0
+  False
+  $ hg log -T "{configint('templateconfig', 'knob', 123)}\n"
+  123
+  $ hg log -T "{configint('templateconfig', 'knob', 123)}\n" \
+  > --config templateconfig.knob=456
+  456
+  $ hg log -T "{config('templateconfig', 'knob')}\n"
+  devel-warn: config item requires an explicit default value: 'templateconfig.knob' at: * (glob)
+  
+  $ hg log -T "{configbool('ui', 'interactive')}\n"
+  False
+  $ hg log -T "{configbool('ui', 'interactive')}\n" --config ui.interactive=1
+  True
+  $ hg log -T "{config('templateconfig', 'knob', if(true, 'foo', 'bar'))}\n"
+  foo
+
   $ cd ..
diff --git a/mercurial/templatefuncs.py b/mercurial/templatefuncs.py
--- a/mercurial/templatefuncs.py
+++ b/mercurial/templatefuncs.py
@@ -295,6 +295,39 @@
         hint = _("get() expects a dict as first argument")
         raise error.ParseError(bytes(err), hint=hint)
 
+ at templatefunc('config(section, name[, default])', requires={'ui'})
+def config(context, mapping, args):
+    """Returns the requested hgrc config option as a string."""
+    fn = context.resource(mapping, 'ui').config
+    return _config(context, mapping, args, fn, evalstring)
+
+ at templatefunc('configbool(section, name[, default])', requires={'ui'})
+def configbool(context, mapping, args):
+    """Returns the requested hgrc config option as a boolean."""
+    fn = context.resource(mapping, 'ui').configbool
+    return _config(context, mapping, args, fn, evalboolean)
+
+ at templatefunc('configint(section, name[, default])', requires={'ui'})
+def configint(context, mapping, args):
+    """Returns the requested hgrc config option as an integer."""
+    fn = context.resource(mapping, 'ui').configint
+    return _config(context, mapping, args, fn, evalinteger)
+
+def _config(context, mapping, args, configfn, defaultfn):
+    if not (2 <= len(args) <= 3):
+        raise error.ParseError(_("config expects two or three arguments"))
+
+    # The config option can come from any section, though we specifically
+    # reserve the [templateconfig] section for dynamically defining options
+    # for this function without also requiring an extension.
+    section = evalstringliteral(context, mapping, args[0])
+    name = evalstringliteral(context, mapping, args[1])
+    if len(args) == 3:
+        default = defaultfn(context, mapping, args[2])
+        return configfn(section, name, default)
+    else:
+        return configfn(section, name)
+
 @templatefunc('if(expr, then[, else])')
 def if_(context, mapping, args):
     """Conditionally execute based on the result of
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -1081,6 +1081,10 @@
     default=None,
     generic=True,
 )
+coreconfigitem('templateconfig', '.*',
+    default=dynamicdefault,
+    generic=True,
+)
 coreconfigitem('trusted', 'groups',
     default=list,
 )



To: rdamazio, #hg-reviewers
Cc: mercurial-devel