Create check to prefer operator== over wxString::Cmp

[LegalizeAdulthood]

Bugzilla Link	28022
Version	unspecified
OS	All
CC	@madsravn

Extended Description

wxWidgets' string class wxString provides operator== for both wxString and wxChar * arguments allowing you to write:

wxString foo;
// ...
if (foo == wxT("foo")) // ...

and

wxString bar;
// ...
if (foo == bar) // ...

It also provides wxString::Cmp which is intended for sorting functions and returns -1, 0, or 1 depending on the lexicographic relationship of the two strings.

Create a clang-tidy check that replaces:
if (!foo.Cmp(wxT("foo"))) // ...
and
if (foo.Cmp(wxT("foo")) == 0)

with

if (foo == wxT("foo")) // ...

Similarly, replace

if (foo.Cmp(wxT("foo"))) // ...
and
if (foo.Cmp(wxT("foo")) != 0) // ...

with

if (foo != wxT("foo"))

This relates to another wxWidgets specific check
https://llvm.org/bugs/show_bug.cgi?id=27300
and both could go in a wxWidgets module

[LegalizeAdulthood]

assigned to @madsravn

[LegalizeAdulthood]

A similar check could be created for std::string::operator== vs std::string::compare.

Most string classes have some sort of lexicographical compare type function to use with sorting algorithms, so this might be a generic string class check with specific support for wxWidgets wxString.

[madsravn]

I will look into this one. Currently I am having a little difficulty matching on the different cases. Hopefully I will have it solved soon.

[LegalizeAdulthood]

Hi Mads, I'm revisiting my old clang bugs. Did you make any progress on this one?

[madsravn]

Hi Mads, I'm revisiting my old clang bugs. Did you make any progress on
this one?

Hi Richard,

I made a new Clang tidy check for std::string::operator== vs std::string::compare. I thought it would be more generic. That could easily be extended to include wxString.

[LegalizeAdulthood]

Great! Yes, the action for this bug is to extend the existing check to allow you to specify the name of a custom string class (instead of std::string) and its associated compare function (instead of std::string::compare).

[LegalizeAdulthood]

It looks like readability-string-compare does the basic job for std::string, but doesn't support additional string-like classes and comparison functions to be supplied via an option, so this issue still applies.