Fix autocomplete for tags beginning with _ or %

Addresses #1598

chrome/content/zotero/xpcom/utilities_internal.js

@@ -1164,6 +1164,15 @@ Zotero.Utilities.Internal = {
 	},
 	
 	
+	/**
+	 * Escape '_', '%', and '\' in an SQL LIKE expression so that it can be used with ESCAPE '\' to
+	 * prevent the wildcards from having special meaning
+	 */
+	escapeSQLExpression: function (expr) {
+		return expr.replace(/([_%\\])/g, '\\$1');
+	},
+	
+	
 	buildLibraryMenu: function (menulist, libraries, selectedLibraryID) {
 		var menupopup = menulist.firstChild;
 		while (menupopup.hasChildNodes()) {

components/zotero-autocomplete.js

@@ -71,8 +71,8 @@ ZoteroAutoComplete.prototype.startSearch = Zotero.Promise.coroutine(function* (s
 			break;
 		
 		case 'tag':
-			var sql = "SELECT DISTINCT name AS val, NULL AS comment FROM tags WHERE name LIKE ?";
-			var sqlParams = [searchString + '%'];
+			var sql = "SELECT DISTINCT name AS val, NULL AS comment FROM tags WHERE name LIKE ? ESCAPE '\\'";
+			var sqlParams = [Zotero.Utilities.Internal.escapeSQLExpression(searchString) + '%'];
 			if (searchParams.libraryID !== undefined) {
 				sql += " AND tagID IN (SELECT tagID FROM itemTags JOIN items USING (itemID) "
 					+ "WHERE libraryID=?)";