A better fix for C++23 P2266R1

After 6d6a143913603b040c10a5db83c2103557899011 "Address some of the sprintf in
vcl/source/fontsubset/cff.cxx", --with-latest-c++ builds that pick up a C++23
compiler that implements
<http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2266r1.html> "P2266R1:
Simpler implicit move" started to fail with something like

> vcl/source/fontsubset/cff.cxx:2061:16: error: no viable conversion from returned value of type 'char[64]' to function return type 'OString'
>         return aDefaultGlyphName;
>                ^~~~~~~~~~~~~~~~~
[...]
> include/rtl/string.hxx:313:5: note: candidate constructor [with T = char[64]] not viable: expects an lvalue for 1st argument
>     OString( T& value, typename libreoffice_internal::NonConstCharArrayDetector< T, libreoffice_internal::Dummy >::Type = libreoffice_internal::Dummy() )
>     ^

etc.  So I figured there should be something better than
433ab39b2175bdadb4916373cd2dc8e1aabc08a5 "Adapt implicit OString return value
construction to C++23 P2266R1" (which this commit reverts, modulo its conflicts
in comphelper/source/xml/xmltools.cxx and
sc/source/filter/xcl97/XclExpChangeTrack.cxx) to address the underlying issue in
a way that keeps code that works up to C++20 also working in C++23.

(The fix is only relevant for non-explicit constructors that involve
NonConstCharArrayDetector and non-const lvalue references, not for other
functions involving those.  OUString has a similar constructor but which is
explicit, and OUStringBuffer doesn't have any similar constructors at all, so
this only affects OString and OStringBuffer constructors.)

Change-Id: I31cf16b9507899f5999243f8467dfa24bc94c5ac
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/142455
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

3 files changed, 3 insertions, 3 deletions

diff --git a/sc/source/filter/excel/xestream.cxx b/sc/source/filter/excel/xestream.cxx
index ee75b188b0f7..0ee697dfeba8 100644
--- a/sc/source/filter/excel/xestream.cxx
+++ b/sc/source/filter/excel/xestream.cxx
@@ -712,7 +712,7 @@ OString XclXmlUtils::ToOString( const Color& rColor )
     char buf[9];
     o3tl::sprintf( buf, "%.2X%.2X%.2X%.2X", rColor.GetAlpha(), rColor.GetRed(), rColor.GetGreen(), rColor.GetBlue() );
     buf[8] = '\0';
-    return OString(buf);
+    return buf;
 }
 
 OStringBuffer& XclXmlUtils::ToOString( OStringBuffer& s, const ScAddress& rAddress )
diff --git a/sc/source/filter/html/htmlexp.cxx b/sc/source/filter/html/htmlexp.cxx
index 4cc01d868603..16db15316121 100644
--- a/sc/source/filter/html/htmlexp.cxx
+++ b/sc/source/filter/html/htmlexp.cxx
@@ -191,7 +191,7 @@ static OString lcl_makeHTMLColorTriplet(const Color& rColor)
     // <font COLOR="#00FF40">hello</font>
     snprintf( buf, 24, "\"#%02X%02X%02X\"", rColor.GetRed(), rColor.GetGreen(), rColor.GetBlue() );
 
-    return OString(buf);
+    return buf;
 }
 
 ScHTMLExport::ScHTMLExport( SvStream& rStrmP, OUString _aBaseURL, ScDocument* pDocP,
diff --git a/sc/source/filter/xcl97/XclExpChangeTrack.cxx b/sc/source/filter/xcl97/XclExpChangeTrack.cxx
index bbee834806c3..57fd143bf659 100644
--- a/sc/source/filter/xcl97/XclExpChangeTrack.cxx
+++ b/sc/source/filter/xcl97/XclExpChangeTrack.cxx
@@ -48,7 +48,7 @@ static OString lcl_DateTimeToOString( const DateTime& rDateTime )
             rDateTime.GetYear(), rDateTime.GetMonth(), rDateTime.GetDay(),
             rDateTime.GetHour(), rDateTime.GetMin(), rDateTime.GetSec(),
             rDateTime.GetNanoSec() );
-    return OString(sBuf);
+    return sBuf;
 }
 
 // local functions