Hide ICU C++ APIs from pg_locale.h

j-naylor · j-naylor · commit ed26c4e25a44 · 2025-07-09T14:20:22.000+07:00
The cpluspluscheck script wraps our headers in `extern "C"`. This disables name mangling, which is necessary for the C++ templates in system ICU headers. cpluspluscheck thus fails when the build is configured with ICU (the default). CI worked around this by disabling ICU, but let's make it work so others can run the script. We can specify we only want the C APIs by defining U_SHOW_CPLUSPLUS_API to be 0 in pg_locale.h. Extensions that want the C++ APIs can include ICU headers separately before including PostgreSQL headers. ICU documentation: https://github.com/unicode-org/icu/blob/main/docs/processes/release/tasks/healthy-code.md#test-icu4c-headers Suggested-by: Andres Freund <andres@anarazel.de> Reviewed-by: Peter Eisentraut <peter@eisentraut.org> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20220323002024.f2g6tivduzrktgfa%40alap3.anarazel.de Discussion: https://postgr.es/m/CANWCAZbgiaz1_0-F4SD%2B%3D-e9onwAnQdBGJbhg94EqUu4Gb7WyA%40mail.gmail.com
diff --git a/.cirrus.tasks.yml b/.cirrus.tasks.yml
@@ -938,14 +938,11 @@ task:
   # - Don't use ccache, the files are uncacheable, polluting ccache's
   #   cache
   # - Use -fmax-errors, as particularly cpluspluscheck can be very verbose
-  # - XXX have to disable ICU to avoid errors:
-  #   https://postgr.es/m/20220323002024.f2g6tivduzrktgfa%40alap3.anarazel.de
   ###
   always:
     headers_headerscheck_script: |
       time ./configure \
         ${LINUX_CONFIGURE_FEATURES} \
-        --without-icu \
         --quiet \
         CC="gcc" CXX"=g++" CLANG="clang-16"
       make -s -j${BUILD_JOBS} clean
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
@@ -15,6 +15,9 @@
 #include "mb/pg_wchar.h"
 
 #ifdef USE_ICU
+/* only include the C APIs, to avoid errors in cpluspluscheck */
+#undef U_SHOW_CPLUSPLUS_API
+#define U_SHOW_CPLUSPLUS_API 0
 #include <unicode/ucol.h>
 #endif
 
