luci-base: runtime.uc: avoid Lua not installed exeption from trycompile()

Make sure to request loading the Lua bridge as optional when initializing
the Lua VM context from trycompile() in order to not raise a fatal exception
in case the Lua runtime support is not present.

Ref: https://forum.openwrt.org/t/x/141426
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 14 insertions, 8 deletions

diff --git a/modules/luci-base/ucode/runtime.uc b/modules/luci-base/ucode/runtime.uc
index d02d8dd667..ed330abcc1 100644
--- a/modules/luci-base/ucode/runtime.uc
+++ b/modules/luci-base/ucode/runtime.uc
@@ -43,13 +43,17 @@ function format_lua_exception(ex) {
 }
 
 const Class = {
-	init_lua: function() {
+	init_lua: function(optional) {
 		if (!this.L) {
-			this.L = this.env.dispatcher.load_luabridge().create();
-			this.L.set('L', proto({ write: print }, this.env));
-			this.L.invoke('require', 'luci.ucodebridge');
+			let bridge = this.env.dispatcher.load_luabridge(optional);
 
-			this.env.lua_active = true;
+			if (bridge) {
+				this.L = bridge.create();
+				this.L.set('L', proto({ write: print }, this.env));
+				this.L.invoke('require', 'luci.ucodebridge');
+
+				this.env.lua_active = true;
+			}
 		}
 
 		return this.L;
@@ -80,10 +84,12 @@ const Class = {
 		}
 		else {
 			try {
-				let vm = this.init_lua();
-				let compile = vm.get('_G', 'luci', 'ucodebridge', 'compile');
+				let vm = this.init_lua(true);
 
-				compile.call(path);
+				if (vm)
+					vm.get('_G', 'luci', 'ucodebridge', 'compile').call(path);
+				else
+					return `Unable to compile '${path}' as Lua template: Unable to load Lua runtime`;
 			}
 			catch (lua_err) {
 				return `Unable to compile '${path}' as Lua template: ${format_lua_exception(lua_err)}`;