xamarin/Xamarin.Forms

Xaml Parser/Compiler does not identify invalid Xaml

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#5,947 opened on Apr 18, 2019

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a/Xaml </>e/2 :clock2:good first issuehelp wantedinactivet/bug :bug:up-for-grabs

Description

Description

The following Xaml, is invalid and does not produce a valid page, but it compiles and parses

Steps to Reproduce

  1. Clone Repo:
  2. Build and Run on iOS
  3. Add an extra > on line 29

Expected Behavior

Compile/Parse error

Actual Behavior

Compiles and parses but does not display right

Reproduction Link

https://github.com/Clancey/gMusic.Forms/

Contributor guide

Tech stack
csharp
Domain
toolingdeveloper experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C#XAML basicsfamiliarity with Xamarin.Forms
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Investigate the XAML parser/compiler code in the Xamarin.Forms repository. The issue at line 29 in SideNavigationPage.xaml shows an extra '>' character that is not flagged. Look at the XAML validation logic, likely in files like XamlParser.cs or XamlCompilation.cs, to see why malformed XAML is silently accepted. Consider adding a test case for this scenario and ensuring the parser detects such syntax errors.
Xaml Parser/Compiler does not identify invalid Xaml · xamarin/Xamarin.Forms#5947 | Good First Issue