dispatch: remove unused _loaded Now, there is no user for dispatch._loaded.

extensions: register functions always at loading extension (issue5601) Before this patch, functions defined in extensions are registered via extra loaders only in _dispatch(). Therefore, loading extensions in other code paths like below omits registration of functions. - WSGI service - operation across repositories (e.g. subrepo) - test-duplicateoptions.py, using extensions.loadall() directly To register functions always at loading new extension, this patch moves implementation for extra loading from dispatch._dispatch() to extensions.loadall(). AFAIK, only commands module causes cyclic dependency between extensions module, but this patch imports all related modules just before extra loading in loadall(), in order to centralize them. This patch makes extensions.py depend on many other modules, even though extensions.py itself doesn't. It should be avoided if possible, but I don't have any better idea. Some other places like below aren't reasonable for extra loading, IMHO. - specific function in newly added module: existing callers of extensions.loadall() should invoke it, too - hg.repository() or so: no-repo commands aren't covered by this. BTW, this patch removes _loaded.add(name) on relocation, because dispatch._loaded is used only for extraloaders (for similar reason, "exts" variable is removed, too).

identify: add template support This is based on a patch proposed last year by Mathias De Maré[1], with a few changes. - Tags and bookmarks are now formatted lists, for more flexible queries. - The templater is populated whether or not [-nibtB] is specified. (Plain output is unchanged.) This seems more consistent with other templated commands. - The 'id' property is a string, instead of a list. - The parents of 'wdir()' have their own list of attributes. I left 'id' as a string because it seems very useful for generating version info. It's also a bit strange because the value and meaning changes depending on whether or not --debug is passed (short vs full hash), whether the revision is a merge or not (one hash or two, separated by a '+'), the working directory or not (node vs p1node), and local or not (remote defaults to tip, and never has '+'). The equivalent string built with {rev} seems much less useful, and I couldn't think of a reasonable name, so I left it out. The discussion seemed to be pointing towards having a list of nodes, with more than one entry for a merge. It seems simpler to give the nodes a name, and use {node} for the actual commit probed, especially now that there is a virtual node for 'wdir()'. Yuya mentioned using fm.nested() in that thread, so I did for the parent nodes. I'm not sure if the plan is to fill in all of the context attributes in these items, or if these nested items should simply be made {p1node} and {p1rev}. I used ':' as the tag separator for consistency with {tags} in the log templater. Likewise, bookmarks are separated by a space for consistency with the corresponding log template. [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2016-August/087039.html