fix: add defaults for optionals, guard against null deref calls (#9)

template/src/schema.zig.ejs

@@ -95,7 +95,7 @@ pub const Host = struct {
 		<% if (p.description) { -%>
 		/// <%- formatCommentBlock(p.description, "/// ") %>
 		<% } -%>
-		<%- p.name %>: <%- p.nullable ? "?" : null %><%- toZigType(p) %>,
+		<%- p.name %>: <%- p.nullable ? "?" : null %><%- toZigType(p) %><%- p.nullable ? " = null" : null %>,
 		<% }) %>
 
 		/// Internally used function, should not be called by plugin authors.
@@ -105,7 +105,13 @@ pub const Host = struct {
 			<% } %>
 			<% schema.properties.forEach(p => { -%>
 			<% if (p.$ref && !p.$ref.enum) { %>
+			<% if (p.nullable) { %>
+			if (self.<%- p.name %> != null) {
+			<% } -%>
 			self.<%- p.name %> = (try self.<%- p.name %>.<%- p.nullable ? '?.' : null %>XXX__decodeBase64Fields()).*;
+			<% if (p.nullable) { %>
+			}
+			<% } -%>
 			<% } else if (p.type === 'buffer') { %>
 			const dest_<%- p.name %> = try std.heap.wasm_allocator.alloc(u8, try b64dec.calcSizeForSlice(self.<%- p.name %>));
 			try b64dec.decode(dest_<%- p.name %>, self.<%- p.name %>);
@@ -123,7 +129,13 @@ pub const Host = struct {
 			<% } %>
 			<% schema.properties.forEach(p => { -%>
 			<% if (p.$ref && !p.$ref.enum) { %>
+			<% if (p.nullable) { %>
+			if (self.<%- p.name %> != null) {
+			<% } -%>
 			self.<%- p.name %> = (try self.<%- p.name %>.<%- p.nullable ? '?.' : null %>XXX__encodeBase64Fields()).*;
+			<% if (p.nullable) { %>
+			}
+			<% } -%>
 			<% } else if (p.type === 'buffer') { %>
 			const dest_<%- p.name %> = try std.heap.wasm_allocator.alloc(u8, b64enc.calcSize(self.<%- p.name %>.len));
 			self.<%- p.name %> = b64enc.encode(dest_<%- p.name %>, self.<%- p.name %>);