mw.ustring functions should accept numbers where string functions do

Lua's string functions tend to auto-convert numbers to strings. We
should do the same in mw.ustring.

Bug: 67201
Change-Id: Icd3c5e93bac19dafd78d737ec9b315daba9f1729

engines/LuaCommon/UstringLibrary.php

@@ -81,6 +81,9 @@ class Scribunto_LuaUstringLibrary extends Scribunto_LuaLibraryBase {
 	}
 
 	private function checkString( $name, $s, $checkEncoding = true ) {
+		if ( $this->getLuaType( $s ) == 'number' ) {
+			$s = (string)$s;
+		}
 		$this->checkType( $name, 1, $s, 'string' );
 		if ( $checkEncoding && !$this->checkEncoding( $s ) ) {
 			throw new Scribunto_LuaError( "bad argument #1 to '$name' (string is not UTF-8)" );
@@ -226,6 +229,9 @@ class Scribunto_LuaUstringLibrary extends Scribunto_LuaLibraryBase {
 	}
 
 	private function checkPattern( $name, $pattern ) {
+		if ( $this->getLuaType( $pattern ) == 'number' ) {
+			$pattern = (string)$pattern;
+		}
 		$this->checkType( $name, 2, $pattern, 'string' );
 		if ( !$this->checkEncoding( $pattern ) ) {
 			throw new Scribunto_LuaError( "bad argument #2 to '$name' (string is not UTF-8)" );
@@ -584,6 +590,7 @@ class Scribunto_LuaUstringLibrary extends Scribunto_LuaLibraryBase {
 
 		switch ( $this->getLuaType( $repl ) ) {
 		case 'string':
+		case 'number':
 			$cb = function ( $m ) use ( $repl, $anypos, &$captures ) {
 				if ( $anypos ) {
 					$m = array_shift( $captures );

engines/LuaCommon/lualib/ustring/ustring.lua

@@ -33,6 +33,9 @@ local function checkType( name, argidx, arg, expecttype, nilok )
 end
 
 local function checkString( name, s )
+	if type( s ) == 'number' then
+		s = tostring( s )
+	end
 	if type( s ) ~= 'string' then
 		local msg = S.format( "bad argument #1 to '%s' (string expected, got %s)",
 			name, type( s )
@@ -48,6 +51,9 @@ local function checkString( name, s )
 end
 
 local function checkPattern( name, pattern )
+	if type( pattern ) == 'number' then
+		pattern = tostring( pattern )
+	end
 	if type( pattern ) ~= 'string' then
 		local msg = S.format( "bad argument #2 to '%s' (string expected, got %s)",
 			name, type( pattern )
@@ -915,6 +921,9 @@ function ustring.gsub( s, pattern, repl, n )
 		tp = 2
 	elseif type( repl ) == 'string' then
 		tp = 3
+	elseif type( repl ) == 'number' then
+		repl = tostring( repl )
+		tp = 3
 	else
 		checkType( 'gsub', 3, repl, 'function or table or string' )
 	end

tests/engines/LuaCommon/UstringLibraryTests.lua

@@ -499,6 +499,18 @@ return testframework.getTestProvider( {
 	  args = { 'foo; fóó', '(%a+)', '%2' },
 	  expect = "invalid capture index %2 in replacement string"
 	},
+	{ name = 'gsub: passing numbers instead of strings (1)', func = mw.ustring.gsub,
+	  args = { 12345, '[3３]', '9' },
+	  expect = { '12945', 1 }
+	},
+	{ name = 'gsub: passing numbers instead of strings (2)', func = mw.ustring.gsub,
+	  args = { '12345', 3, '9' },
+	  expect = { '12945', 1 }
+	},
+	{ name = 'gsub: passing numbers instead of strings (3)', func = mw.ustring.gsub,
+	  args = { '12345', '[3３]', 9 },
+	  expect = { '12945', 1 }
+	},
 
 	{ name = 'gcodepoint: basic test', func = mw.ustring.gcodepoint,
 	  args = { str1 },