Rule: MA0006 Use String.Equals instead of equality operator

[kimlundjohansen]

Rule summary

	Value
Title	Use String.Equals instead of equality operator
CheckId	MA0006
Category	?
Link	https://github.com/meziantou/Meziantou.Analyzer/blob/master/docs/Rules/MA0006.md

What is the problem

This does not improve readability as the rules description claims.

Suggestion

disable this rule in root .editorconfig with dotnet_diagnostic.MA0006.severity = none

[egil]

What StringComparison style is used with a == b? If it is not StringComparison.Ordinal, then a.Equals(b, StringComparison.Ordinal will perform better.

Besides that, I agree that it does NOT improve readability.

[cjakobsen]

This documentation from Microsoft also speaks against using == for comparison so I think we should keep it.

[MrAndersPedersen]

Please red comment from cjacobsen.

[rickykaare]

As far as I understand using == for comparing two strings will be the same as using string.Equals() with StringComparison.Ordinal (given that the two strings are of type string, and not cast to e.g. object).

In my mind, this way of comparing strings are by far the most commonly used, so applying the MA0006 rule in general would add a lot of clutter.

In most cases I think it would be very obvious if you need to compare using case-insensitivity or the CurrentCulture, and then use the string.Equals() instead.

[egil]

As far as I understand using == for comparing two strings will be the same as using string.Equals() with StringComparison.Ordinal

That's surprising to me @rickykaare, but you are right, at least if we read the latest string.cs code. Here we see that EqualsHelper is called when from both the operators ==/!= and from the Equals method when StringComparison.Ordinal is set.

That takes the performance concern out of the equation for me. The question that is left is whether we want to be explicit in our code about our intentions, e.g. signaling that, yes, we have thought about culture and this is what we want.

[egil]

ROOT=NONE, because in most cases we are only doing ordinal comparisons anyway, and == leads to cleaner code.

Exception to this rule when working on an application that is multi cultured.

[davidkallesen]

https://github.com/atc-net/atc-coding-rules/blob/main/documentation/CodeAnalyzersRules/Meziantou/MA0006.md