Save dependencies for template hooks properly

Kwpolska · Kwpolska · commit 581e340fed85 · 2017-05-22T16:19:50.000+02:00
Signed-off-by: Chris Warrick &lt;kwpolska@gmail.com&gt;
diff --git a/CHANGES.txt b/CHANGES.txt
@@ -16,6 +16,8 @@ Features
 Bugfixes
 --------
 
+* Save dependencies for template hooks properly (using .__doc__ or
+  .template_registry_identifier for callables)
 * Enable larger panorama thumbnails (Issue #2780)
 * Disable ``archive_rss`` link handler, which was useless because no
   such RSS was ever generated (Issue #2783)
diff --git a/docs/extending.txt b/docs/extending.txt
@@ -537,21 +537,22 @@ HTML:
 
     # In set_site
     def generate_html_bit(name, ftype='js'):
+        """Generate HTML for an asset."""
         return '<script src="/assets/{t}/{n}.{t}">'.format(n=name, t=ftype)
 
-    site.template_hooks['extra_head'].append(generate_html_bit, False, 'fancyplugin', type='js')
+    site.template_hooks['extra_head'].append(generate_html_bit, False, 'fancyplugin', ftype='js')
 
 
 The second argument to ``append()`` is used to determine whether the function
 needs access to the current template context and the site.  If it is set to
 ``True``, the function will also receive ``site`` and ``context`` keyword
 arguments.  Example use:
 
-
 .. code-block:: python
 
     # In set_site
     def greeting(addr, endswith='', site=None, context=None):
+        """Greet someone."""
         if context['lang'] == 'en':
             greet = u'Hello'
         elif context['lang'] == 'es':
@@ -564,6 +565,13 @@ arguments.  Example use:
 
     site.template_hooks['page_header'].append(greeting, True, u'Nikola Tesla', endswith=u'!')
 
+Dependencies for template hooks:
+
+* if the input is a string, the string value, alongside arguments to ``append``, is used for calculating dependencies
+* if the input is a callable, it attempts ``input.template_registry_identifier``, then ``input.__doc__``, and if neither is available, it uses a static string.
+
+Make sure to provide at least a docstring, or a identifier, to ensure rebuilds work properly.
+
 Shortcodes
 ==========
 
@@ -579,7 +587,7 @@ So, if you are creating a plugin that generates markup, it may be a good idea
 to register it as a shortcode in addition of to restructured text directive or
 markdown extension, thus making it available to all markup formats.
 
-To implement your own shortcodes from a plugin, you can create a plugin inheriting ``ShortcodePlugin`` and 
+To implement your own shortcodes from a plugin, you can create a plugin inheriting ``ShortcodePlugin`` and
 from its ``set_site`` method,  call
 
 ``Nikola.register_shortcode(name, func)`` with the following arguments:
@@ -610,7 +618,7 @@ variable keyword arguments):
     between them, otherwise ``None``.
 
 ``lang``:
-    The current language.    
+    The current language.
 
 If the shortcode tag has arguments of the form ``foo=bar`` they will be
 passed as named arguments. Everything else will be passed as positional
diff --git a/nikola/nikola.py b/nikola/nikola.py
@@ -2243,7 +2243,7 @@ def generic_renderer(self, lang, output_name, template_name, filters, file_deps=
             deps_dict.update(post_deps_dict)
 
         for k, v in self.GLOBAL_CONTEXT['template_hooks'].items():
-            deps_dict['||template_hooks|{0}||'.format(k)] = v._items
+            deps_dict['||template_hooks|{0}||'.format(k)] = v.calculate_deps()
 
         for k in self._GLOBAL_CONTEXT_TRANSLATABLE:
             deps_dict[k] = deps_dict['global'][k](lang)
diff --git a/nikola/plugins/task/galleries.py b/nikola/plugins/task/galleries.py
@@ -173,7 +173,7 @@ def gen_tasks(self):
         self.image_ext_list.extend(self.site.config.get('EXTRA_IMAGE_EXTENSIONS', []))
 
         for k, v in self.site.GLOBAL_CONTEXT['template_hooks'].items():
-            self.kw['||template_hooks|{0}||'.format(k)] = v._items
+            self.kw['||template_hooks|{0}||'.format(k)] = v.calculate_deps()
 
         self.site.scan_posts()
         yield self.group_task()
diff --git a/nikola/plugins/task/listings.py b/nikola/plugins/task/listings.py
@@ -187,7 +187,7 @@ def render_listing(in_name, out_name, input_folder, output_folder, folders=[], f
                 uptodate = {'c': self.site.GLOBAL_CONTEXT}
 
                 for k, v in self.site.GLOBAL_CONTEXT['template_hooks'].items():
-                    uptodate['||template_hooks|{0}||'.format(k)] = v._items
+                    uptodate['||template_hooks|{0}||'.format(k)] = v.calculate_deps()
 
                 for k in self.site._GLOBAL_CONTEXT_TRANSLATABLE:
                     uptodate[k] = self.site.GLOBAL_CONTEXT[k](self.kw['default_lang'])
diff --git a/nikola/utils.py b/nikola/utils.py
@@ -512,9 +512,23 @@ def append(self, inp, wants_site_and_context=False, *args, **kwargs):
         c = callable(inp)
         self._items.append((c, inp, wants_site_and_context, args, kwargs))
 
+    def calculate_deps(self):
+        """Calculate dependencies for a registry."""
+        deps = []
+        for is_callable, inp, wants_site_and_context, args, kwargs in self._items:
+            if not is_callable:
+                name = inp
+            elif hasattr(inp, 'template_registry_identifier'):
+                name = inp.template_registry_identifier
+            elif hasattr(inp, '__doc__'):
+                name = inp.__doc__
+            else:
+                name = '_undefined_callable_'
+            deps.append((is_callable, name, wants_site_and_context, args, kwargs))
+
     def __hash__(self):
         """Return hash of a registry."""
-        return hash(config_changed({self.name: self._items})._calc_digest())
+        return hash(config_changed({self.name: self.calculate_deps()})._calc_digest())
 
     def __str__(self):
         """Stringify a registry."""
