Hide edit toolbar Signature button in non-discussion namespaces

Most wikis only use user signatures on pages set aside from discussion,
(Talk namespaces and sometimes project/main namespaces depending on
the wiki), so having the button available everywhere is confusing.
The few wikis that need the button (especially non-content,
internal/corporate/planning wikis), can add relevant namespaces to the
$wgExtraSignatureNamespaces array in LocalSettings.

This would make it possible to solve bugs like T59727 or T53154.

Since this is a change to default behavior, a release note is added.

Bug: T7645
Change-Id: I7ccf1093b888c7b33721234349ca0ac054c3cd3f

RELEASE-NOTES-1.26

@@ -16,6 +16,10 @@ production.
   use the 'rawcontinue' parameter to receive raw query-continue data, but the
   new style is encouraged as it's harder to implement incorrectly.
 * Deprecated API formats dump and wddx have been completely removed.
+* (T7645) The "Signature" button on the edit toolbar is now hidden by default
+  in non-talk namespaces. A new configuration variable,
+  $wgExtraSignatureNamespaces, controls in which subject (non-talk) namespaces
+  the "Signature" button on the edit toolbar will be displayed.
 * $wgResourceLoaderUseESI was deprecated and removed. This was an experimental
   feature that was never enabled by default.
 

includes/DefaultSettings.php

@@ -3962,6 +3962,15 @@ $wgTrackingCategories = array();
  */
 $wgContentNamespaces = array( NS_MAIN );
 
+/**
+ * Array of namespaces, in addition to the talk namespaces, where signatures
+ * (~~~~) are likely to be used. This determines whether to display the
+ * Signature button on the edit toolbar, and may also be used by extensions.
+ * For example, "traditional" style wikis, where content and discussion are
+ * intermixed, could place NS_MAIN and NS_PROJECT namespaces in this array.
+ */
+$wgExtraSignatureNamespaces = array();
+
 /**
  * Max number of redirects to follow when resolving redirects.
  * 1 means only the first redirect is followed (default behavior).

includes/EditPage.php

@@ -2545,7 +2545,7 @@ class EditPage {
 		$wgOut->addHTML( $this->editFormTextBeforeContent );
 
 		if ( !$this->isCssJsSubpage && $showToolbar && $wgUser->getOption( 'showtoolbar' ) ) {
-			$wgOut->addHTML( EditPage::getEditToolbar() );
+			$wgOut->addHTML( EditPage::getEditToolbar( $this->mTitle ) );
 		}
 
 		if ( $this->blankArticle ) {
@@ -3686,13 +3686,18 @@ HTML
 	 * Shows a bulletin board style toolbar for common editing functions.
 	 * It can be disabled in the user preferences.
 	 *
+	 * @param $title Title object for the page being edited (optional)
 	 * @return string
 	 */
-	static function getEditToolbar() {
+	static function getEditToolbar( $title = null ) {
 		global $wgContLang, $wgOut;
 		global $wgEnableUploads, $wgForeignFileRepos;
 
 		$imagesAvailable = $wgEnableUploads || count( $wgForeignFileRepos );
+		$showSignature = true;
+		if ( $title ) {
+			 $showSignature = MWNamespace::wantSignatures( $title->getNamespace() );
+		}
 
 		/**
 		 * $toolarray is an array of arrays each of which includes the
@@ -3760,13 +3765,13 @@ HTML
 				'sample' => wfMessage( 'nowiki_sample' )->text(),
 				'tip'    => wfMessage( 'nowiki_tip' )->text(),
 			),
-			array(
+			$showSignature ? array(
 				'id'     => 'mw-editbutton-signature',
 				'open'   => '--~~~~',
 				'close'  => '',
 				'sample' => '',
 				'tip'    => wfMessage( 'sig_tip' )->text(),
-			),
+			) : false,
 			array(
 				'id'     => 'mw-editbutton-hr',
 				'open'   => "\n----\n",

includes/MWNamespace.php

@@ -296,6 +296,18 @@ class MWNamespace {
 		return $index == NS_MAIN || in_array( $index, $wgContentNamespaces );
 	}
 
+	/**
+	 * Might pages in this namespace require the use of the Signature button on
+	 * the edit toolbar?
+	 *
+	 * @param int $index Index to check
+	 * @return bool
+	 */
+	public static function wantSignatures( $index ) {
+		global $wgExtraSignatureNamespaces;
+		return self::isTalk( $index ) || in_array( $index, $wgExtraSignatureNamespaces );
+	}
+
 	/**
 	 * Can pages in a namespace be watched?
 	 *

includes/resourceloader/ResourceLoaderStartUpModule.php

@@ -88,6 +88,7 @@ class ResourceLoaderStartUpModule extends ResourceLoaderModule {
 			'wgContentNamespaces' => MWNamespace::getContentNamespaces(),
 			'wgSiteName' => $conf->get( 'Sitename' ),
 			'wgDBname' => $conf->get( 'DBname' ),
+			'wgExtraSignatureNamespaces' => $conf->get( 'ExtraSignatureNamespaces' ),
 			'wgAvailableSkins' => Skin::getSkinNames(),
 			'wgExtensionAssetsPath' => $conf->get( 'ExtensionAssetsPath' ),
 			// MediaWiki sets cookies to have this prefix by default