Deprecate $wgLegalTitleChars and $wgIllegalFileChars

In https://gerrit.wikimedia.org/r/c/mediawiki/core/+/745386 and
https://lists.wikimedia.org/hyperkitty/list/wikitech-l@lists.wikimedia.org/thread/ASODV6622T4YUAY3JO5ZVBL3B5ZQDX2U/
a compelling case is made that we can drop $wgLegalTitleChars as a
configuration option.  Extension::TitleBlacklist or, in the near
future, Extension:AbuseFilter can be used to restrict the character
set for those who still have that need.

Similarly, it doesn't seem compelling to make IllegalFileChars
configurable; probably most libraries don't even realize that the
set of legal title characters after a `File:` prefix is different
from the set of legal title characters, and of those that actually
implement this, probably no one is actually respecting a reconfigured
value for $wgIllegalFileChars, because it's not even exported in
siteinfo.

A patch to remove the configurability will land later (probably based
on I70b60ca548e36c676da90553ad8684507096bb28) but for now let's just
announce our intention to fix the set of legal title/file characters
for all wikis and let that ride out into the world in our next
release.

Bug: T297340
Change-Id: If48257ff6e800451b992ed0748abc878fa5e16d3

2 files changed, 7 insertions, 0 deletions

diff --git a/docs/config-schema.yaml b/docs/config-schema.yaml
index c3bf7e886096..503ef60839f7 100755
--- a/docs/config-schema.yaml
+++ b/docs/config-schema.yaml
@@ -424,11 +424,13 @@ config-schema:
         description: 'To disable file delete/restore temporarily'
     IllegalFileChars:
         default: ':\/\\'
+        deprecated: 'since 1.41; no longer customizable'
         description: |-
             Additional characters that are not allowed in filenames. They are replaced with '-' when
             uploading. Like $wgLegalTitleChars, this is a regexp character class.
             Slashes and backslashes are disallowed regardless of this setting, but included here for
             completeness.
+            @deprecated since 1.41; no longer customizable
     DeletedDirectory:
         default: false
         dynamicDefault:
@@ -3838,6 +3840,7 @@ config-schema:
             including those defined by other means.
     LegalTitleChars:
         default: ' %!"$&''()*,\-.\/0-9:;=?@A-Z\\^_`a-z~\x80-\xFF+'
+        deprecated: 'since 1.41; use Extension:TitleBlacklist to customize'
         description: |-
             Allowed title characters -- regex character class
             Don't change this unless you know what you're doing
@@ -3857,6 +3860,8 @@ config-schema:
             passed in the query string rather than the path. This is a minor security issue
             because articles can be created such that they are hard to view or edit.
             In some rare cases you may wish to remove + for compatibility with old links.
+            @deprecated since 1.41; use Extension:TitleBlacklist or (soon)
+            Extension:AbuseFilter to customize this set.
     CapitalLinks:
         default: true
         description: |-
diff --git a/docs/config-vars.php b/docs/config-vars.php
index 36bc082c7020..d934540ee862 100755
--- a/docs/config-vars.php
+++ b/docs/config-vars.php
@@ -253,6 +253,7 @@ $wgUploadMaintenance = null;
 /**
  * Config variable stub for the IllegalFileChars setting, for use by phpdoc and IDEs.
  * @see MediaWiki\MainConfigSchema::IllegalFileChars
+ * @deprecated since 1.41; no longer customizable
  */
 $wgIllegalFileChars = null;
 
@@ -2157,6 +2158,7 @@ $wgNamespaceAliases = null;
 /**
  * Config variable stub for the LegalTitleChars setting, for use by phpdoc and IDEs.
  * @see MediaWiki\MainConfigSchema::LegalTitleChars
+ * @deprecated since 1.41; use Extension:TitleBlacklist to customize
  */
 $wgLegalTitleChars = null;