rspec/rules/S4056/csharp/rule.adoc

== Why is this an issue?

When a ``++System.Globalization.CultureInfo++`` or ``++IFormatProvider++`` object is not supplied, the default value that is supplied by the overloaded member might not have the effect that you want in all locales.

You should supply culture-specific information according to the following guidelines:

* If the value will be displayed to the user, use the current culture. See ``++CultureInfo.CurrentCulture++``.
* If the value will be stored and accessed by software (persisted to a file or database), use the invariant culture. See ``++CultureInfo.InvariantCulture++``.
* If you do not know the destination of the value, have the data consumer or provider specify the culture.

This rule raises an issue when a method or constructor calls one or more members that have overloads that accept a ``++System.IFormatProvider++`` parameter, and the method or constructor does not call the overload that takes the ``++IFormatProvider++`` parameter. This rule ignores calls to .NET Framework methods that are documented as ignoring the ``++IFormatProvider++`` parameter as well as the following methods:

* ``++Activator.CreateInstance++``
* ``++ResourceManager.GetObject++``
* ``++ResourceManager.GetString++``


=== Noncompliant code example

[source,csharp]
----
using System;

namespace MyLibrary
{
    public class Foo
    {
        public void Bar(String string1)
        {
            if(string.Compare(string1, string2, false) == 0) // Noncompliant
            {
                Console.WriteLine(string3.ToLower()); // Noncompliant
            }
        }
    }
}
----


=== Compliant solution

[source,csharp]
----
using System;
using System.Globalization;

namespace MyLibrary
{
    public class Foo
    {
        public void Bar(String string1, String string2, String string3)
        {
            if(string.Compare(string1, string2, false, 
                              CultureInfo.InvariantCulture) == 0)
            {
                Console.WriteLine(string3.ToLower(CultureInfo.CurrentCulture));
            }
        }
    }
}
----


=== Exceptions

This rule will not raise an issue when the overload is marked as obsolete.


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Use the overload that takes a "CultureInfo" or "IFormatProvider" parameter.


=== Highlighting

Method or constructor call


'''
== Comments And Links
(visible only on this page)

=== on 15 Apr 2019, 10:36:01 Andrei Epure wrote:
\[~nicolas.harraudeau] - should we consider https://docs.microsoft.com/en-us/dotnet/api/system.stringcomparison?view=netframework-4.7.2[StringComparison] as well (because is implies CultureInfo)?

=== on 15 Apr 2019, 18:23:22 Nicolas Harraudeau wrote:
Not for now. We need to dig this a little more. Collation issues have usually less impact than encoding issues. We might have to create a separate rule.

endif::env-github,rspecator-view[]