Bug 28760 - System.Text.Encoding.UTF8.GetString returns corrupted string
Summary: System.Text.Encoding.UTF8.GetString returns corrupted string
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: 3.12.0
Hardware: PC Linux
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2015-04-03 21:35 UTC by webmaster
Modified: 2015-04-08 19:53 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

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Description webmaster 2015-04-03 21:35:07 UTC
mono 3.12.1
os: ubuntu server 14.04 (64 bit)

BitConverter.ToString(System.Text.Encoding.UTF8.GetBytes("a中文显示d")) returns the following valid byte array


but the following will not return the original string


it's somehow corrupted, namely a Console.Write of the aobove gives "a?????a".
Comment 1 webmaster 2015-04-03 21:47:40 UTC
OK, even Console.WriteLine("a中文显示d") doesn't print the original text ...
Comment 2 webmaster 2015-04-04 00:10:41 UTC
But "a中文显示d" == System.Text.Encoding.UTF8.GetString(System.Text.Encoding.UTF8.GetBytes("a中文显示d")) returns true.
Comment 3 webmaster 2015-04-04 00:58:07 UTC
By the way, the above anormaly happens in nodejs environment (mono is accessed via edge.js). I checked if I am running a top level console application, the above problem does not appear.
Comment 4 webmaster 2015-04-04 01:04:47 UTC
In order to avoid potential problems in marshaling layer, the text is base64 encoded in nodejs part and decoded inside mono part:

var edge = require('edge');
var base64 = require('js-base64').Base64;

var f = edge.func(function () {/*
    async (input) => {
        var buf = Convert.FromBase64String(input as string);
        var x = System.Text.Encoding.UTF8.GetString(buf);
        Console.WriteLine("v82clr: `" + x + "`");
        Console.WriteLine("a中文显示d" == x);
        return x;

var k = "a中文显示d";
var r = f(base64.encode(k), true);
console.log('original: "' + k +'"');
console.log('clr2v8: `' + r + '`');
Comment 5 Marek Safar 2015-04-08 13:15:17 UTC
It works for me with normal console.
Comment 6 webmaster 2015-04-08 19:53:17 UTC
Did you tried to run it inside of the nodejs + edgejs environment, like what's shown above? It's fine (namely not "corrupted") if one start the mono process inside a shell.

What I found is that on my server specified above (two of them, one physical machine, one virtual machine) it is not really corrupted but the console inside of the nodejs + edgejs can not display utf-8 strings event the "LANG" environment variable is set properly in the execution context. Maybe it is because the font directories were not inherited from parent process or some other problems.

I belief it is still a problem if not a very important one. For example, it mislead us to a wrong direction in finding a real encoding setting problem in other part of our system. But I am not sure it is mono's problem or not.