Add support for wxNO_IMPLICIT_WXSTRING_CONV_TO_PTR to wxString

This symbol is similar to the existing wxNO_IMPLICIT_WXSTRING_ENCODING
and can be defined when building the application (as opposed to when
building the library) to disable implicit wxString conversions to
pointer types, i.e. char*, wchat_t* and void*.

This makes the just added wxUSE_CHAR_CONV_IN_WXSTRING library build
option unnecessary, so remove it.

build/cmake/options.cmake

@@ -90,7 +90,6 @@ wx_dependent_option(wxUSE_UTF8_LOCALE_ONLY "only support UTF-8 locales in UTF-8
 if(NOT WIN32)
     wx_option(wxUSE_VISIBILITY "use of ELF symbols visibility")
 endif()
-wx_option(wxUSE_CHAR_CONV_IN_WXSTRING "provide implicit conversions to const wchar_t* and const char* in wxString" ON)
 wx_option(wxUSE_STD_STRING_CONV_IN_WXSTRING "provide implicit conversions to std::wstring and std::string in wxString" OFF)
 wx_option(wxUSE_UNSAFE_WXSTRING_CONV "provide unsafe implicit conversions in wxString to const char* or std::string")
 wx_option(wxUSE_REPRODUCIBLE_BUILD "enable reproducable build" OFF)

build/cmake/setup.h.in

@@ -159,8 +159,6 @@
 
 #cmakedefine01 wxUSE_UNSAFE_WXSTRING_CONV
 
-#cmakedefine01 wxUSE_CHAR_CONV_IN_WXSTRING
-
 #cmakedefine01 wxUSE_STD_STRING_CONV_IN_WXSTRING
 
 

configure

@@ -1122,7 +1122,6 @@ with_cxx
 enable_stl
 enable_std_containers
 enable_std_iostreams
-enable_char_conv_in_wxstring
 enable_std_string_conv_in_wxstring
 enable_unsafe_conv_in_wxstring
 enable_utf8
@@ -2089,7 +2088,6 @@ Optional Features:
   --enable-stl            obsolete option doing nothing
   --disable-std_containers disable use of standard C++ container classes
   --disable-std_iostreams  disable use of standard C++ stream classes
- --disable-char_conv_in_wxstring     disable implicit conversion to const wchar_t/char* in wxString
  --enable-std_string_conv_in_wxstring     provide implicit conversion to std::string in wxString
  --disable-unsafe_conv_in_wxstring        disable unsafe implicit conversions in wxString
   --enable-utf8           use UTF-8 representation for strings
@@ -5637,35 +5635,6 @@ fi
           eval "$wx_cv_use_std_iostreams"
 
 
-          enablestring=disable
-          defaultval=
-          if test -z "$defaultval"; then
-              if test x"$enablestring" = xdisable; then
-                  defaultval=yes
-              else
-                  defaultval=no
-              fi
-          fi
-
-          # Check whether --enable-char_conv_in_wxstring was given.
-if test "${enable_char_conv_in_wxstring+set}" = set; then :
-  enableval=$enable_char_conv_in_wxstring;
-                          if test "$enableval" = yes; then
-                            wx_cv_use_char_conv_in_wxstring='wxUSE_CHAR_CONV_IN_WXSTRING=yes'
-                          else
-                            wx_cv_use_char_conv_in_wxstring='wxUSE_CHAR_CONV_IN_WXSTRING=no'
-                          fi
-
-else
-
-                          wx_cv_use_char_conv_in_wxstring='wxUSE_CHAR_CONV_IN_WXSTRING=${'DEFAULT_wxUSE_CHAR_CONV_IN_WXSTRING":-$defaultval}"
-
-fi
-
-
-          eval "$wx_cv_use_char_conv_in_wxstring"
-
-
           enablestring=
           defaultval=
           if test -z "$defaultval"; then
@@ -37464,11 +37433,6 @@ if test "$wxUSE_STD_IOSTREAM" = "yes"; then
 
 fi
 
-if test "$wxUSE_CHAR_CONV_IN_WXSTRING" = "yes"; then
-  $as_echo "#define wxUSE_CHAR_CONV_IN_WXSTRING 1" >>confdefs.h
-
-fi
-
 if test "$wxUSE_STD_STRING_CONV_IN_WXSTRING" = "yes"; then
   $as_echo "#define wxUSE_STD_STRING_CONV_IN_WXSTRING 1" >>confdefs.h
 

configure.in

@@ -642,7 +642,6 @@ AC_ARG_WITH(cxx,           [  --with-cxx=11|14|17|20  use the given C++ dialect]
 WX_ARG_ENABLE(stl,         [  --enable-stl            obsolete option doing nothing], wxUSE_STL)
 WX_ARG_DISABLE(std_containers,[  --disable-std_containers disable use of standard C++ container classes], wxUSE_STD_CONTAINERS)
 WX_ARG_DISABLE(std_iostreams,[  --disable-std_iostreams  disable use of standard C++ stream classes], wxUSE_STD_IOSTREAM)
-WX_ARG_DISABLE(char_conv_in_wxstring, [ --disable-char_conv_in_wxstring     disable implicit conversion to const wchar_t/char* in wxString], wxUSE_CHAR_CONV_IN_WXSTRING)
 WX_ARG_ENABLE(std_string_conv_in_wxstring, [ --enable-std_string_conv_in_wxstring     provide implicit conversion to std::string in wxString], wxUSE_STD_STRING_CONV_IN_WXSTRING)
 WX_ARG_DISABLE(unsafe_conv_in_wxstring,     [ --disable-unsafe_conv_in_wxstring        disable unsafe implicit conversions in wxString], wxUSE_UNSAFE_WXSTRING_CONV)
 WX_ARG_ENABLE_PARAM(utf8,    [  --enable-utf8           use UTF-8 representation for strings], wxUSE_UNICODE_UTF8)
@@ -5391,10 +5390,6 @@ if test "$wxUSE_STD_IOSTREAM" = "yes"; then
   AC_DEFINE(wxUSE_STD_IOSTREAM)
 fi
 
-if test "$wxUSE_CHAR_CONV_IN_WXSTRING" = "yes"; then
-  AC_DEFINE(wxUSE_CHAR_CONV_IN_WXSTRING)
-fi
-
 if test "$wxUSE_STD_STRING_CONV_IN_WXSTRING" = "yes"; then
   AC_DEFINE(wxUSE_STD_STRING_CONV_IN_WXSTRING)
 fi

docs/doxygen/mainpages/const_wxusedef.h

@@ -43,7 +43,7 @@ library:
     available.}
 @itemdef{wxUSE_UNSAFE_WXSTRING_CONV, Defined as 1 by default for compatibility,
     but can be set to 0 to globally disable unsafe implicit conversions in
-    wxString class. See @ref overview_string_settings for more details.}
+    wxString class. See @ref string_conv for more details.}
 @endDefList
 
 

include/wx/android/setup.h

@@ -284,7 +284,7 @@
 // ----------------------------------------------------------------------------
 
 // Provide unsafe implicit conversions in wxString to "const char*" or
-// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+// "std::string" (only if implicit conversions are not disabled entirely).
 //
 // Default is 1 for compatibility reasons, it is recommended to set
 // this to 0 because converting wxString to a narrow (non-Unicode) string may
@@ -297,16 +297,6 @@
 // application code to effectively disallow using these conversions.
 #define wxUSE_UNSAFE_WXSTRING_CONV 1
 
-// Define implicit conversions of wxString to "const wchar_t*" and "const
-// char*" if wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
-//
-// Default is 1.
-//
-// Recommended setting: 1 to remain compatible with the official builds of
-// wxWidgets but may be set to 0 to prevent any accidental conversions from
-// happening.
-#define wxUSE_CHAR_CONV_IN_WXSTRING 1
-
 // Define implicit conversions of wxString to std::wstring and std::string if
 // wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
 //
@@ -314,9 +304,9 @@
 // this option is turned on or off, it only enables implicit conversion in the
 // other direction.
 //
-// If this setting is changed to 1, wxUSE_CHAR_CONV_IN_WXSTRING must be set to
+// If this setting is changed to 1, implicit conversions to pointer types are
-// 0 as setting both of them to 1 will result in ambiguities due to having too
+// disabled as defining both kinds of implicit conversions would result in
-// many implicit conversions defined.
+// ambiguities.
 //
 // Default is 0.
 //

include/wx/gtk/setup.h

@@ -285,7 +285,7 @@
 // ----------------------------------------------------------------------------
 
 // Provide unsafe implicit conversions in wxString to "const char*" or
-// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+// "std::string" (only if implicit conversions are not disabled entirely).
 //
 // Default is 1 for compatibility reasons, it is recommended to set
 // this to 0 because converting wxString to a narrow (non-Unicode) string may
@@ -298,16 +298,6 @@
 // application code to effectively disallow using these conversions.
 #define wxUSE_UNSAFE_WXSTRING_CONV 1
 
-// Define implicit conversions of wxString to "const wchar_t*" and "const
-// char*" if wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
-//
-// Default is 1.
-//
-// Recommended setting: 1 to remain compatible with the official builds of
-// wxWidgets but may be set to 0 to prevent any accidental conversions from
-// happening.
-#define wxUSE_CHAR_CONV_IN_WXSTRING 1
-
 // Define implicit conversions of wxString to std::wstring and std::string if
 // wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
 //
@@ -315,9 +305,9 @@
 // this option is turned on or off, it only enables implicit conversion in the
 // other direction.
 //
-// If this setting is changed to 1, wxUSE_CHAR_CONV_IN_WXSTRING must be set to
+// If this setting is changed to 1, implicit conversions to pointer types are
-// 0 as setting both of them to 1 will result in ambiguities due to having too
+// disabled as defining both kinds of implicit conversions would result in
-// many implicit conversions defined.
+// ambiguities.
 //
 // Default is 0.
 //

include/wx/msw/setup.h

@@ -285,7 +285,7 @@
 // ----------------------------------------------------------------------------
 
 // Provide unsafe implicit conversions in wxString to "const char*" or
-// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+// "std::string" (only if implicit conversions are not disabled entirely).
 //
 // Default is 1 for compatibility reasons, it is recommended to set
 // this to 0 because converting wxString to a narrow (non-Unicode) string may
@@ -298,16 +298,6 @@
 // application code to effectively disallow using these conversions.
 #define wxUSE_UNSAFE_WXSTRING_CONV 1
 
-// Define implicit conversions of wxString to "const wchar_t*" and "const
-// char*" if wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
-//
-// Default is 1.
-//
-// Recommended setting: 1 to remain compatible with the official builds of
-// wxWidgets but may be set to 0 to prevent any accidental conversions from
-// happening.
-#define wxUSE_CHAR_CONV_IN_WXSTRING 1
-
 // Define implicit conversions of wxString to std::wstring and std::string if
 // wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
 //
@@ -315,9 +305,9 @@
 // this option is turned on or off, it only enables implicit conversion in the
 // other direction.
 //
-// If this setting is changed to 1, wxUSE_CHAR_CONV_IN_WXSTRING must be set to
+// If this setting is changed to 1, implicit conversions to pointer types are
-// 0 as setting both of them to 1 will result in ambiguities due to having too
+// disabled as defining both kinds of implicit conversions would result in
-// many implicit conversions defined.
+// ambiguities.
 //
 // Default is 0.
 //

include/wx/osx/setup.h

@@ -291,7 +291,7 @@
 // ----------------------------------------------------------------------------
 
 // Provide unsafe implicit conversions in wxString to "const char*" or
-// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+// "std::string" (only if implicit conversions are not disabled entirely).
 //
 // Default is 1 for compatibility reasons, it is recommended to set
 // this to 0 because converting wxString to a narrow (non-Unicode) string may
@@ -304,16 +304,6 @@
 // application code to effectively disallow using these conversions.
 #define wxUSE_UNSAFE_WXSTRING_CONV 1
 
-// Define implicit conversions of wxString to "const wchar_t*" and "const
-// char*" if wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
-//
-// Default is 1.
-//
-// Recommended setting: 1 to remain compatible with the official builds of
-// wxWidgets but may be set to 0 to prevent any accidental conversions from
-// happening.
-#define wxUSE_CHAR_CONV_IN_WXSTRING 1
-
 // Define implicit conversions of wxString to std::wstring and std::string if
 // wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
 //
@@ -321,9 +311,9 @@
 // this option is turned on or off, it only enables implicit conversion in the
 // other direction.
 //
-// If this setting is changed to 1, wxUSE_CHAR_CONV_IN_WXSTRING must be set to
+// If this setting is changed to 1, implicit conversions to pointer types are
-// 0 as setting both of them to 1 will result in ambiguities due to having too
+// disabled as defining both kinds of implicit conversions would result in
-// many implicit conversions defined.
+// ambiguities.
 //
 // Default is 0.
 //

include/wx/setup_inc.h

@@ -281,7 +281,7 @@
 // ----------------------------------------------------------------------------
 
 // Provide unsafe implicit conversions in wxString to "const char*" or
-// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+// "std::string" (only if implicit conversions are not disabled entirely).
 //
 // Default is 1 for compatibility reasons, it is recommended to set
 // this to 0 because converting wxString to a narrow (non-Unicode) string may
@@ -294,16 +294,6 @@
 // application code to effectively disallow using these conversions.
 #define wxUSE_UNSAFE_WXSTRING_CONV 1
 
-// Define implicit conversions of wxString to "const wchar_t*" and "const
-// char*" if wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
-//
-// Default is 1.
-//
-// Recommended setting: 1 to remain compatible with the official builds of
-// wxWidgets but may be set to 0 to prevent any accidental conversions from
-// happening.
-#define wxUSE_CHAR_CONV_IN_WXSTRING 1
-
 // Define implicit conversions of wxString to std::wstring and std::string if
 // wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
 //
@@ -311,9 +301,9 @@
 // this option is turned on or off, it only enables implicit conversion in the
 // other direction.
 //
-// If this setting is changed to 1, wxUSE_CHAR_CONV_IN_WXSTRING must be set to
+// If this setting is changed to 1, implicit conversions to pointer types are
-// 0 as setting both of them to 1 will result in ambiguities due to having too
+// disabled as defining both kinds of implicit conversions would result in
-// many implicit conversions defined.
+// ambiguities.
 //
 // Default is 0.
 //

include/wx/string.h

@@ -98,6 +98,14 @@ class WXDLLIMPEXP_FWD_BASE wxString;
     #endif
 #endif // wxUSE_UNSAFE_WXSTRING_CONV
 
+// enabling implicit conversions to std::[w]string is incompatible with having
+// implicit conversions to char*/wchar_t*.
+#if wxUSE_STD_STRING_CONV_IN_WXSTRING
+    #ifndef wxNO_IMPLICIT_WXSTRING_CONV_TO_PTR
+        #define wxNO_IMPLICIT_WXSTRING_CONV_TO_PTR
+    #endif
+#endif // wxUSE_STD_STRING_CONV_IN_WXSTRING
+
 namespace wxPrivate
 {
     template <typename T> struct wxStringAsBufHelper;
@@ -1540,7 +1548,7 @@ public:
     // implicit conversion to wxCStrData
     operator wxCStrData() const { return c_str(); }
 
-#if wxUSE_CHAR_CONV_IN_WXSTRING
+#if !defined(wxNO_IMPLICIT_WXSTRING_CONV_TO_PTR)
     operator const wchar_t*() const { return c_str(); }
 
 #if !defined(wxNO_UNSAFE_WXSTRING_CONV)
@@ -1551,7 +1559,7 @@ public:
     operator const void*() const { return c_str(); }
 #endif // !defined(wxNO_UNSAFE_WXSTRING_CONV)
 
-#endif // wxUSE_CHAR_CONV_IN_WXSTRING
+#endif // !defined(wxNO_IMPLICIT_WXSTRING_CONV_TO_PTR)
 
     // identical to c_str(), for MFC compatibility
     const wxCStrData GetData() const { return c_str(); }

include/wx/univ/setup.h

@@ -284,7 +284,7 @@
 // ----------------------------------------------------------------------------
 
 // Provide unsafe implicit conversions in wxString to "const char*" or
-// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+// "std::string" (only if implicit conversions are not disabled entirely).
 //
 // Default is 1 for compatibility reasons, it is recommended to set
 // this to 0 because converting wxString to a narrow (non-Unicode) string may
@@ -297,16 +297,6 @@
 // application code to effectively disallow using these conversions.
 #define wxUSE_UNSAFE_WXSTRING_CONV 1
 
-// Define implicit conversions of wxString to "const wchar_t*" and "const
-// char*" if wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
-//
-// Default is 1.
-//
-// Recommended setting: 1 to remain compatible with the official builds of
-// wxWidgets but may be set to 0 to prevent any accidental conversions from
-// happening.
-#define wxUSE_CHAR_CONV_IN_WXSTRING 1
-
 // Define implicit conversions of wxString to std::wstring and std::string if
 // wxUSE_UNSAFE_WXSTRING_CONV is also enabled.
 //
@@ -314,9 +304,9 @@
 // this option is turned on or off, it only enables implicit conversion in the
 // other direction.
 //
-// If this setting is changed to 1, wxUSE_CHAR_CONV_IN_WXSTRING must be set to
+// If this setting is changed to 1, implicit conversions to pointer types are
-// 0 as setting both of them to 1 will result in ambiguities due to having too
+// disabled as defining both kinds of implicit conversions would result in
-// many implicit conversions defined.
+// ambiguities.
 //
 // Default is 0.
 //

interface/wx/string.h

@@ -139,17 +139,20 @@
     becomes unavailable -- but explicit conversions using c_str() and mb_str()
     still work.
 
-    Finally, please note that implicit conversion to both `const char*` and
+    Finally, please note that implicit conversion to both `const char*` (which
-    `const wchar_t*` may be entirely disabled by setting the build option
+    is unsafe for the reasons explained above) and to `const wchar_t*` (which
-    `wxUSE_CHAR_CONV_IN_WXSTRING` to 0. Unlike with `wxNO_XXX` constants, this
+    is safe from this point of view, but may still be considered dangerous, as
-    option requires rebuilding the library after changing its value.
+    any implicit conversion) may be entirely disabled by defining
+    `wxNO_IMPLICIT_WXSTRING_CONV_TO_PTR` when building the application.
 
 
     To summarize, the safest way to use wxString is to always define
     `wxNO_IMPLICIT_WXSTRING_ENCODING` in the application compilation options to
     disable all implicit uses of encoding and specify it explicitly, typically
     by using utf8_str() or utf8_string() and FromUTF8() for conversions, for
-    every operation.
+    every operation. If this is impossible, for example because it would
+    require too many changes to the existing code, consider defining
+    `wxNO_UNSAFE_WXSTRING_CONV` to at least disable implicit unsafe conversions.
 
 
     @section string_gotchas Traps for the unwary

setup.h.in

@@ -162,8 +162,6 @@
 
 #define wxUSE_UNSAFE_WXSTRING_CONV 0
 
-#define wxUSE_CHAR_CONV_IN_WXSTRING 0
-
 #define wxUSE_STD_STRING_CONV_IN_WXSTRING 0
 
 

setup.h_vms

@@ -195,8 +195,6 @@ typedef pid_t GPid;
 
 #define wxUSE_STD_CONTAINERS 0
 
-#define wxUSE_CHAR_CONV_IN_WXSTRING 1
-
 #define wxUSE_STD_STRING_CONV_IN_WXSTRING 0
 
 #define wxUSE_LONGLONG      1

tests/strings/strings.cpp

@@ -1018,7 +1018,7 @@ TEST_CASE("StringCStrDataImplicitConversion", "[wxString]")
     CHECK( CheckStrConstWChar(s, s.c_str()) );
     CHECK( CheckStrConstChar(s, s.c_str()) );
 
-#if wxUSE_CHAR_CONV_IN_WXSTRING
+#ifndef wxNO_IMPLICIT_WXSTRING_CONV_TO_PTR
     CHECK( CheckStrConstWChar(s, s) );
 #ifndef wxNO_UNSAFE_WXSTRING_CONV
     CHECK( CheckStrConstChar(s, s) );