I think this could be quite useful also for templates that should always be used
with subst for other reasons. Examples are broiler-plate notifications to users
(those messages should not change over time) and deletion requests that contain
a link to a subpage by day (as is the case on the german wp for example). There
is constant trouble with people forgetting the subst: part. This feature could
solve that.

As for the marker, I would suggest SUBST, to be consistent with other
meta-markers used in mediawiki (like NOTOC and such).

netoholic wrote:

This is an amazingly good idea. I see TONS of potential uses for this. Currently, our only option is for a bot to run
through pages using these sorts of templates and replace them with subst: calls - a task which is done almost never.

changed bug summary to be more descriptive

pete wrote:

As a user I also would be grateful if this feature were implemented

M.Schouten wrote:

The setting of such a flag is impossible/hard to undo. What I think we need is
to _not parse_ anything in the template namespace. Then I could make a template
vfd_ and a template vfd with as only code {{subst:vfd_}}. Then using {{vfd}}
would result in substitution of {{vfd_}} always. It would also make it possible
to use the dates in templates, simply by using {{subst:DAY}}, which because of
not parsing would end up in the article if this template was substituted there.

JoostMeerten wrote:

The setting of such a flag is trivial to undo: remove the SUBST. I'm not
sure what the problem is—of course you cannot undo setting that flag
''retroactively'', but that is impossible ''no matter what'' solution you come
up with for forcing substitution. The whole idea behind substitution is that you
don't keep track of changes to the original.

Likewise, the inclusion code for that is very easy: instead of putting in the
template contents, you first scan for SUBST (you'll have to read the
contents anyway), and if you find it, simply turn on substitution as if subst:
had been used in the link. This is a simple enhancement to the input layer.

Your suggestion is far more drastical, and is very likely to break existing
templates.

avarab wrote:

*** Bug 2476 has been marked as a duplicate of this bug. ***

p_simoons wrote:

Strongly support this. We're presently working on a bot that would automatically
subst certain templates, but putting it in software would be better.

zocky wrote:

I also strongly support this. If we need to have a way to override forced
substitution, we can have something like {{transclude:pagename}}.

So, {{pagename}} by default transcludes, alternatively substitutes if SUBST
is found, {{subst:pagename}} always substitutes and {{transclude:pagename}}
always transcludes.

gangleri wrote:

bug 2777: request for a {{substall:foo}} beside {{subst:bar}}
is a request about substitution to be done at all levels of nested templates. It
is a nice to have which saves would save time because as evetery level would
equire a save in orther that "subst" would take effect.
The syntax discussed here should still ofer a way to implement "substall".

philsand wrote:

This is indeed a very important feature - frankly, teh template namespace is kind of getting out of control with stuff that has no
reason not to be substed - I've increasingly seen templates that are just article text that people want in multiple articles that are
being done with straight template usage - and often with meta-templates. This is both a server load problem and a new user
problem - templates are not intuitively editable. The ability to force substitution of a template would provide a solution to these
problems that does not depend on tedious debate to get people to realize that they're being dense.

rowan.collins wrote:

I'm not sure how a SUBST flag would ever decrease the amount of debate
necessary - we can already have debates about whether to add "<noinclude>please
always use subst: for this</noinclude>", and we'll still need debates about
whether to use "SUBST". I guess it might cut down the number of people
saying "well, *why* should I always use subst:?", but they'll still want to know
"*why* does it contain SUBST" (quite apart from those who will be just plain
surprised that it works at all).

Nor can I see how putting text in multiple articles would ever have anything to
do with this: if they wanted a subst, they'd already be using one - or just
using copy-and-paste, which is all "subst" is, really.

All that being said, I do see that this could be a useful feature, simply as an
"idiot-proofing" flag for templates that should be being used this way already.
We'd have to make sure the flag was *only* read during the "pre-save transform"
stage, else a vandal could cause a whole host of pages to be changed on next
view. Even then, there's the potential for someone to, say, replace a stub
template with "This article sucks!!! SUBST", and watch as everyone else
inadvertently vandalises articles by editting them and substing in that text,
but I guess that would be easy enough for an expert-ish user to spot.

ayg wrote:

I would suggest that rather than being a wikitext setting like TOC, this be
a database flag settable by checkbox/special page/whatever (or it could just be
an array, take your pick). Ability to set the flag could be restricted by
usergroup, such as to admins in Wikipedia's case, and furthermore it would be
much faster to check for when doing a page save (at least naïvely; of course,
the SUBST flag could be implemented as actually setting a database flag).

wikiGracenotes wrote:

Due to possible abuse, I (like Simetrical) would suggest that only a certain
user group (admin sounds good as default) could set a template to be substituted
by default -- a flag or mode sort of like page protection, semi-protection, and
cascade protection... I wrote a bit about it at
http://en.wikipedia.org/w/index.php?title=Wikipedia:Village_pump_%28technical%29&oldid=105666294#Forcing_template_substitution
It would need to be applied by a admin (a trusted editor, I hope), not just any
person, to limit possible edit wars. There might need to be an inverse to
"subst", something like "trans", to enable transclusion when needed. This is a
good idea, I think; it could go in a lot of directions.

z9z8z-wps wrote:

I don't think this is a good idea at all. There is {{x}} and {{subst:x}} and who cares knows about it and does not want to get confused by
different behaviour. There would be no way to tell quickly off-hand whether a template would be substituted or not.

The only way I can think of to make this work in a less disturbing way would be to re-introduce {{msg:x}} for transclusion, leaving {{subst:x}}
for substitution and {{x}} for whatever a SUBST or other marker in the template indicates with a default for possibly transclusion. Then, on
an edit, {{x}} would be changed to either {{msg:x}} or the template text, so that {{x}} would just be a shorthand to a default and never be stored
as "{{x}}" itself.

However in my opinion it is less troublesome to have users learn the proper use of templates.

bugzilla.wikimedia wrote:

I just independently came up with this proposed enhancement myself, and I thought
the SUBST marker (good proposal, that) should only change the default;
templates can then still be transcluded with {{msg:x}} / substituted with
{{subst:x}}, overriding the default (of course, another option might be to
prohibit the overrides at the admin level).

A workaround for the vandalism problem, apart from access control, might be to
replace all {{x}} by either {{msg:x}} or {{subst:x}} when an article is saved,
thus overriding the default and making the article impervious to a change of the
default. The downside is that this may make the wiki source a little dense with
all those msg: and subst: flags.

esprit15d wrote:

I think that this is a great idea also. While I know that some think it is better to train someone, I've learned that the workload at the Wikis is staggering when you think about it, and people tend to do things they want to do. Figuring out templates and following regulations are usually not at the top of the list of the kind of user who would use a template to add text an article's mainspace. I would have to problem with this feature being restricted to admins, and I think the SUBST idea would work nicely.

MediaWiki wrote:

There are huge issues with this, at least on en.wp. Last time I generated a list, I had over 50,000 pages that were improperly transcluding one supposed-to-be-subst:'ed template. If the template ever changes (rare but possible), the Wikimedia servers will probably go bonkers. I'm doing what I can in AWB, but it's slow; 50,000 pages could take several months at the edit rates I can maintain.

Simply adding a SUBST or (I think this is better) FORCESUBST marker would be good. Making it a checkbox on the edit page accessible only to a certain (configurable) level of user would be OK.

The only thing is, it wouldn't fix the huge unsubsted backlogs; they'd have to wait until the page was next edited, and then it would look funny to the user making the edit ("I didn't subst: that. What's going on?"). It would prevent future additions to that monolithic list, though.

This would be tremendously useful.

circeus wrote:

How can we prevent this from being used for vandalism: forcing a mildly popular, but not large use template to substitue could be extremely annoying and would have to be reverted on every page, especially if the template is changed at the same time (e.g. to obscenities or hate speech). I don't think such an option, if it is added, should be enabled on any mediawiki project ever.

MediaWiki wrote:

(In reply to comment #20)

How can we prevent this from being used for vandalism: forcing a mildly
popular, but not large use template to substitue could be extremely annoying
and would have to be reverted on every page, especially if the template is
changed at the same time (e.g. to obscenities or hate speech). I don't think
such an option, if it is added, should be enabled on any mediawiki project
ever.

It is possible that the feature could be used for vandalism, but a vandal who edits a template and then includes it on a lot of pages where it isn't supposed to be used would have to be reverted on each page anyway. There's not really much change except the text that would have to be reverted ({{template}} versus ''wikicode'' [[markup]]).

emddudley wrote:

(In reply to comment #21)

(In reply to comment #20)

How can we prevent this from being used for vandalism: forcing a mildly

It is possible that the feature could be used for vandalism, but a vandal who
edits a template and then includes it on a lot of pages where it isn't supposed
to be used would have to be reverted on each page anyway. There's not really
much change except the text that would have to be reverted ({{template}} versus
''wikicode'' [[markup]]).

I think you missed carrick's point. What would happen if the keyword was added to a template that was already used on many pages? If all the pages using the template were automatically substed, then reverting the template would not fix all the pages. If the pages were not automatically substed, then we'd have an inconsistency where pages are using a template that is supposed to be subst-only.

MediaWiki wrote:

(In reply to comment #22)

I think you missed carrick's point. What would happen if the keyword was added
to a template that was already used on many pages? If all the pages using the
template were automatically substed, then reverting the template would not fix
all the pages. If the pages were not automatically substed, then we'd have an
inconsistency where pages are using a template that is supposed to be
subst-only.

Perhaps it shouldn't be a wikicode marker, then. Maybe another action like 'protect' or 'delete' that can be restricted by user group. A simple checkbox on the edit page would probably do it. That is, if( userCan( 'marksubstonly' ) ) { echo $checkbox; }

Or something along those lines. Thoughts?

ayg wrote:

As I said in comment 13 more than eighteen months ago, this should be restricted by usergroup. I will now go further and say that this will almost definitely not be implemented without restriction by usergroup, barring some clever way to retroactively reverse the change (unlikely).

There are other issues with this. Currently there should be no way for any article's saved text to contain the text {{subst:templatename}} (there are a couple of obscure ones, but those are bugs). This necessarily creates a way for that situation to arise. This means that if I set Template:Template to subst automatically, and it's already used in some pages, the next person to edit the page will appear to have replaced the template call with a whole bunch of literal wikitext, and it won't be clear whether it was done automatically (without the user's knowledge!) or manually. If the template contained vandalism for whatever reason, the user would appear to be a vandal.

Even if you avoid this by having a dedicated pseudo-user that will insert a revision substituting the template before the edit, say -- if so, this would be the *only* such pseudo-user to edit a large number of pages, which essentially introduces a new concept to most editors and might be confusing -- templates that must be substed but aren't are still in a kind of limbo. What happens to them if the master template changes? Logically their value should be fixed as of the time the subst-only flag is added, but how will that work? What if the revision as of the time the subst-only flag was added later got deleted, or even oversighted?

Do you do all the substitutions immediately when the flag is added? You can't; it needs to be put on the job queue, which means the problem remains. Do you store the text to substitute in the job? Then say the revision needs to be oversighted (possibly due to a rogue admin, or an admin tricked by a clever vandal). You'll have a stream of pages over the course of hours having the oversight-required text being added to them, with no central record of where it's being added, and no way to stop it short of getting someone with database access to manually figure out which jobs are which and delete the appropriate ones.

Substing to the current revision, as of whenever the job gets around to it, is probably the only feasible solution, but it creates issues too. Presumably the interface will indicate that editing the template will not affect existing pages, but that will be false while jobs are pending. You could have a different message displayed while it's still included in some pages, which could be checked using templatelinks. Also, what happens if the entire template is deleted while jobs are pending? Probably then you want to leave the template call alone -- the job would have to check this before substing.

Even if all the above is handled, the previous revisions of the page will still contain calls to the template, which is invalid. This is probably not a problem, since you could just treat them as you would in a preview, showing the current value of the template, which is what they meant to do anyway (since they originally transcluded instead of substing).

There may be other issues as well. Tim is probably the one to ask about this.

circeus wrote:

I have to admit I had not remembered originally that a page must be edited in any case for substitution to occur, but I think the point still stand, and the inability to track substitution will combine with the issue should this be implemented... has a substitution log ever been suggested?

Why not just have a tag <nosubst> whose content is removed by subst:, so it is only displayed if the template is transcluded? (a functionality somewhat similar to <noinclude> and <includeonly>)

This way, you can display a big ugly warning to the user who misses the subst:, add the page to a special category or whatever you want. Much less intrusive than the other proposed changes.

MediaWiki wrote:

(In reply to comment #26)

Why not just have a tag <nosubst> whose content is removed by subst:, so it is
only displayed if the template is transcluded? (a functionality somewhat
similar to <noinclude> and <includeonly>)

This way, you can display a big ugly warning to the user who misses the subst:,
add the page to a special category or whatever you want. Much less intrusive
than the other proposed changes.

Dude, you rock! Why didn't I think of that?

ayg wrote:

That's bug 4484. This is a different request.

esprit15d wrote:

(In reply to comment #22)

(In reply to comment #21)

(In reply to comment #20)

How can we prevent this from being used for vandalism: forcing a mildly

It is possible that the feature could be used for vandalism, but a vandal who
edits a template and then includes it on a lot of pages where it isn't supposed
to be used would have to be reverted on each page anyway. There's not really
much change except the text that would have to be reverted ({{template}} versus
''wikicode'' [[markup]]).

I think you missed carrick's point. What would happen if the keyword was added
to a template that was already used on many pages? If all the pages using the
template were automatically substed, then reverting the template would not fix
all the pages. If the pages were not automatically substed, then we'd have an
inconsistency where pages are using a template that is supposed to be
subst-only.

This is where the admin, or approved user, restriction comes in. This is a common and established method for a boadload of scripts and templates already. It would be easy to implement here as well.

jopiswezggzmw wrote:

I have written an extension to do this: http://www.mediawiki.org/wiki/Extension:SubstControl

It works using two MediaWiki: namespace pages to list templates that should always and should never be substituted, therefore only sysops (by default) can specify which templates should be affected. I have no idea if it stable enough for the likes of Wikipedia though.

I have made a suggestion to add a marker for TemplateData that forces a template to be always substituted ( https://www.mediawiki.org/wiki/Topic:X713ii14s1xz1csk ).