doesn't compile with newer clang

[hoeflerb]

When running install.packages('testthat') with a recent Clang:

* installing *source* package ‘testthat’ ...
** this is package ‘testthat’ version ‘3.2.3’
** package ‘testthat’ successfully unpacked and MD5 sums checked
** using staged installation
** libs
using C compiler: ‘Homebrew clang version 21.1.0’
using C++ compiler: ‘Homebrew clang version 21.1.0’
using SDK: ‘MacOSX15.2.sdk’

<snip>

/opt/homebrew/opt/llvm/bin/clang++ -I"/opt/homebrew/Cellar/r/4.5.1/lib/R/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -I/opt/homebrew/include -I/opt/homebrew/opt/llvm/include -I/opt/homebrew/opt/openssl/include -I/opt/homebrew/opt/gettext/include	-I/opt/homebrew/opt/tcl-tk/include -DCATCH_CONFIG_CPP11_NO_SHUFFLE -Wno-missing-template-arg-list-after-template-kw    -fPIC  -g -O3 -Wall -pedantic -mtune=native -pipe  -c test-runner.cpp -o test-runner.o
In file included from test-runner.cpp:7:
In file included from ../inst/include/testthat.h:1:
In file included from ../inst/include/testthat/testthat.h:72:
../inst/include/testthat/vendor/catch.h:7187:18: error: no member named 'random_shuffle' in namespace 'std'
 7187 |             std::random_shuffle( vector.begin(), vector.end() );
      |                  ^~~~~~~~~~~~~~
In file included from test-runner.cpp:7:
In file included from ../inst/include/testthat.h:1:
In file included from ../inst/include/testthat/testthat.h:170:
In file included from /opt/homebrew/Cellar/r/4.5.1/lib/R/include/R.h:70:
/opt/homebrew/Cellar/r/4.5.1/lib/R/include/R_ext/Boolean.h:62:36: warning: unknown warning group '-Wfixed-enum-extension', ignored [-Wunknown-warning-option]
   62 | #  pragma clang diagnostic ignored "-Wfixed-enum-extension"
      |                                    ^
1 warning and 1 error generated.
make: *** [test-runner.o] Error 1
ERROR: compilation failed for package ‘testthat’
* removing ‘/opt/homebrew/lib/R/4.5/site-library/testthat’

According to this, std::random_shuffle was deprecated in C++14 and removed in C++17, and C++17 is the default standard for Clang versions 16 and higher.

I can make this build by forcing C++14 in my Makevars file, but it would be great if this can be fixed at the source.

[kevinushey]

Hmm... if there were really an issue, I would've expected one of the various CRAN checks to have failed with testthat.

Catch should be detecting and enabling C++11's std::shuffle() here:

testthat/inst/include/testthat/vendor/catch.h

Lines 313 to 315 in 387580b

	#if defined(CATCH_INTERNAL_CONFIG_CPP11_SHUFFLE) && !defined(CATCH_CONFIG_CPP11_NO_SHUFFLE) && !defined(CATCH_CONFIG_CPP11_SHUFFLE) && !defined(CATCH_CONFIG_NO_CPP11)
	# define CATCH_CONFIG_CPP11_SHUFFLE
	#endif

and then that gets used here:

testthat/inst/include/testthat/vendor/catch.h

Lines 7191 to 7197 in 387580b

	#ifdef CATCH_CONFIG_CPP11_SHUFFLE
	std::random_device device;
	std::mt19937 rng( device() );
	std::shuffle( vector.begin(), vector.end(), rng );
	#else
	std::random_shuffle( vector.begin(), vector.end() );
	#endif

I'll see if I can reproduce and figure out why it's failing in this scenario.

[kevinushey]

Works on my macOS machine:

$ /opt/homebrew/bin/R CMD INSTALL --preclean .
* installing to library ‘/Users/kevin/Library/R/homebrew/aarch64/4.5/library’
* installing *source* package ‘testthat’ ...
** this is package ‘testthat’ version ‘3.2.3.9000’
** using staged installation
** libs
using C compiler: ‘Homebrew clang version 21.1.0’
using C++ compiler: ‘Homebrew clang version 21.1.0’
using SDK: ‘MacOSX15.5.sdk’
/opt/homebrew/opt/llvm/bin/clang -I"/opt/homebrew/Cellar/r/4.5.1/lib/R/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -I/opt/homebrew/opt/gettext/include -I/opt/homebrew/opt/readline/include -I/opt/homebrew/opt/xz/include -I/opt/homebrew/include    -fPIC  -g -O2 -Wall -c init.c -o init.o
In file included from init.c:1:
In file included from /opt/homebrew/Cellar/r/4.5.1/lib/R/include/R.h:70:
/opt/homebrew/Cellar/r/4.5.1/lib/R/include/R_ext/Boolean.h:62:36: warning: unknown warning group '-Wfixed-enum-extension', ignored [-Wunknown-warning-option]
   62 | #  pragma clang diagnostic ignored "-Wfixed-enum-extension"
      |                                    ^
1 warning generated.
/opt/homebrew/opt/llvm/bin/clang++ -I"/opt/homebrew/Cellar/r/4.5.1/lib/R/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -I/opt/homebrew/opt/gettext/include -I/opt/homebrew/opt/readline/include -I/opt/homebrew/opt/xz/include -I/opt/homebrew/include    -fPIC  -g -O2 -Wall  -c test-catch.cpp -o test-catch.o
/opt/homebrew/opt/llvm/bin/clang++ -I"/opt/homebrew/Cellar/r/4.5.1/lib/R/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -I/opt/homebrew/opt/gettext/include -I/opt/homebrew/opt/readline/include -I/opt/homebrew/opt/xz/include -I/opt/homebrew/include    -fPIC  -g -O2 -Wall  -c test-example.cpp -o test-example.o
/opt/homebrew/opt/llvm/bin/clang++ -I"/opt/homebrew/Cellar/r/4.5.1/lib/R/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -I/opt/homebrew/opt/gettext/include -I/opt/homebrew/opt/readline/include -I/opt/homebrew/opt/xz/include -I/opt/homebrew/include    -fPIC  -g -O2 -Wall  -c test-runner.cpp -o test-runner.o
In file included from test-runner.cpp:7:
In file included from ../inst/include/testthat.h:1:
In file included from ../inst/include/testthat/testthat.h:170:
In file included from /opt/homebrew/Cellar/r/4.5.1/lib/R/include/R.h:70:
/opt/homebrew/Cellar/r/4.5.1/lib/R/include/R_ext/Boolean.h:62:36: warning: unknown warning group '-Wfixed-enum-extension', ignored [-Wunknown-warning-option]
   62 | #  pragma clang diagnostic ignored "-Wfixed-enum-extension"
      |                                    ^
1 warning generated.
/opt/homebrew/opt/llvm/bin/clang++ -dynamiclib -Wl,-headerpad_max_install_names -undefined dynamic_lookup -L/opt/homebrew/Cellar/r/4.5.1/lib/R/lib -L/opt/homebrew/opt/gettext/lib -L/opt/homebrew/opt/readline/lib -L/opt/homebrew/opt/xz/lib -L/opt/homebrew/lib -o testthat.so init.o test-catch.o test-example.o test-runner.o -L/opt/homebrew/Cellar/r/4.5.1/lib/R/lib -lR
installing to /Users/kevin/Library/R/homebrew/aarch64/4.5/library/00LOCK-testthat/00new/testthat/libs
** R
** inst
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
*** copying figures
** building package indices
** installing vignettes
** testing if installed package can be loaded from temporary location
** checking absolute paths in shared objects and dynamic libraries
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (testthat)

[kevinushey]

/opt/homebrew/opt/llvm/bin/clang++ -I"/opt/homebrew/Cellar/r/4.5.1/lib/R/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -I/opt/homebrew/include -I/opt/homebrew/opt/llvm/include -I/opt/homebrew/opt/openssl/include -I/opt/homebrew/opt/gettext/include -I/opt/homebrew/opt/tcl-tk/include -DCATCH_CONFIG_CPP11_NO_SHUFFLE -Wno-missing-template-arg-list-after-template-kw -fPIC -g -O3 -Wall -pedantic -mtune=native -pipe -c test-runner.cpp -o test-runner.o

Why do you have -DCATCH_CONFIG_CPP11_NO_SHUFFLE set? Maybe that was in response to:

testthat/NEWS.md

Lines 289 to 292 in 387580b

	* Fixed an issue that could prevent compilation of Catch unit tests with
	LLVM 15. In the interim, packages needing a local workaround can set
	`PKG_CPPFLAGS = -DCATCH_CONFIG_CPP11_NO_SHUFFLE` in their `src/Makevars`.
	(@kevinushey, #1687)

and you just need to remove that now?

[hoeflerb]

Doh! 🙄

(note to self: check compiler flags before filing bug reports)

Thanks Kevin for looking into it. Indeed, I had set that flag as a past workaround and had forgotten about it.

[hoeflerb]

Compilation works fine now.