Follow up r45741 per IAlex comment:

OutputPage::wrapWikiMsg() directly adds the html to OutputPage::$mBodytext rather than returning it.

diff --git a/includes/EditPage.php b/includes/EditPage.php
index de38703..ee16922 100644 (file)
--- a/includes/EditPage.php
+++ b/includes/EditPage.php
@@ -177,7 +177,7 @@ class EditPage {
                                        }
                                        if ( $result ) {
                                                # Inform the user of our success and set an automatic edit summary
-                                               $this->editFormPageTop .= $wgOut->wrapWikiMsg( '<div class="mw-undo-success">$1</div>', 'undo-success' );
+                                               $this->editFormPageTop .= $wgOut->parse( '<div class="mw-undo-success">' . wfMsgNoTrans( 'undo-success' ) . '</div>' );
                                                $firstrev = $oldrev->getNext();
                                                # If we just undid one rev, use an autosummary
                                                if ( $firstrev->mId == $undo ) {
@@ -186,13 +186,13 @@ class EditPage {
                                                $this->formtype = 'diff';
                                        } else {
                                                # Warn the user that something went wrong
-                                               $this->editFormPageTop .= $wgOut->wrapWikiMsg( '<div class="error mw-undo-failure">$1</div>', 'undo-failure' );
+                                               $this->editFormPageTop .= $wgOut->parse( '<div class="error mw-undo-failure">' . wfMsgNoTrans( 'undo-failure' ) . '</div>' );
                                        }
                                } else {
                                        // Failed basic sanity checks.
                                        // Older revisions may have been removed since the link
                                        // was created, or we may simply have got bogus input.
-                                       $this->editFormPageTop .= $wgOut->wrapWikiMsg( '<div class="error mw-undo-norev">$1</div>', 'undo-norev' );
+                                       $this->editFormPageTop .= $wgOut->parse( '<div class="error mw-undo-norev">' . wfMsgNoTrans( 'undo-norev' ) . '</div>' );
                                }
                        } else if ( $section != '' ) {
                                if ( $section == 'new' ) {