Installation on macOS fails to find brew libudunits

[t-kalinowski]

Console session of an installation attempt of the dev package on a pretty vanilla macOS setup:

tomasz@tomaszkalinows-WQVX units % brew install udunits 
Warning: udunits 2.2.28 is already installed and up-to-date.
To reinstall 2.2.28, run:
  brew reinstall udunits
tomasz@tomaszkalinows-WQVX units % Rscript -e 'remotes::install_local()'

── R CMD build ─────────────────────────────────────────────────────────────────
   checking for file ‘/private/var/folders/bg/pzsh15_96957bg6ylzt60tyc0000gp/T/R✔  checking for file ‘/private/var/folders/bg/pzsh15_96957bg6ylzt60tyc0000gp/T/RtmpXE3bKJ/file10f3d7616dbea/units/DESCRIPTION’
─  preparing ‘units’:
✔  checking DESCRIPTION meta-information ...
─  cleaning src
─  running ‘cleanup’
─  checking for LF line-endings in source and make files and shell scripts
─  checking for empty or unneeded directories
─  building ‘units_0.8-6.tar.gz’
   
Installing package into ‘/Users/tomasz/Library/R/arm64/4.4/library’
(as ‘lib’ is unspecified)
* installing *source* package ‘units’ ...
** using staged installation
configure: units: 0.8-6
checking whether the C++ compiler works... yes
checking for C++ compiler default output file name... a.out
checking for suffix of executables... 
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether the compiler supports GNU C++... yes
checking whether clang++ -arch arm64 -std=gnu++17 accepts -g... yes
checking for clang++ -arch arm64 -std=gnu++17 option to enable C++11 features... none needed
checking for stdio.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for strings.h... yes
checking for sys/stat.h... yes
checking for sys/types.h... yes
checking for unistd.h... yes
checking for _Bool... no
checking for stdbool.h that conforms to C99 or later... yes
checking for error_at_line... no
checking for gcc... clang -arch arm64
checking whether the compiler supports GNU C... yes
checking whether clang -arch arm64 accepts -g... yes
checking for clang -arch arm64 option to enable C11 features... none needed
checking for XML_ParserCreate in -lexpat... yes
checking for udunits2.h... no
checking for udunits2/udunits2.h... no
checking for ut_read_xml in -ludunits2... no
configure: error: in '/private/var/folders/bg/pzsh15_96957bg6ylzt60tyc0000gp/T/Rtmpg7l1oF/R.INSTALL10f8e160a3137/units':
configure: error: 
--------------------------------------------------------------------------------
  Configuration failed because libudunits2.so was not found. Try installing:
    * deb: libudunits2-dev (Debian, Ubuntu, ...)
    * rpm: udunits2-devel (Fedora, EPEL, ...)
    * brew: udunits (OSX)
  If udunits2 is already installed in a non-standard location, use:
    --configure-args='--with-udunits2-lib=/usr/local/lib'
  if the library was not found, and/or:
    --configure-args='--with-udunits2-include=/usr/include/udunits2'
  if the header was not found, replacing paths with appropriate values.
  You can alternatively set UDUNITS2_INCLUDE and UDUNITS2_LIBS manually.
--------------------------------------------------------------------------------

See 'config.log' for more details
ERROR: configuration failed for package ‘units’
* removing ‘/Users/tomasz/Library/R/arm64/4.4/library/units’
* restoring previous ‘/Users/tomasz/Library/R/arm64/4.4/library/units’
Warning message:
In i.p(...) :
  installation of package ‘/var/folders/bg/pzsh15_96957bg6ylzt60tyc0000gp/T//RtmpXE3bKJ/file10f3d1ce6160b/units_0.8-6.tar.gz’ had non-zero exit status
tomasz@tomaszkalinows-WQVX units % find /opt/homebrew/lib | grep udunits
/opt/homebrew/lib/libudunits2.0.dylib
/opt/homebrew/lib/libudunits2.a
/opt/homebrew/lib/libudunits2.dylib
tomasz@tomaszkalinows-WQVX units % find /opt/homebrew | grep udunits 
/opt/homebrew/bin/udunits2
/opt/homebrew/include/udunits.h
/opt/homebrew/include/udunits2.h
/opt/homebrew/var/homebrew/linked/udunits
/opt/homebrew/lib/libudunits2.0.dylib
/opt/homebrew/lib/libudunits2.a
/opt/homebrew/lib/libudunits2.dylib
/opt/homebrew/opt/udunits
/opt/homebrew/Cellar/udunits
/opt/homebrew/Cellar/udunits/2.2.28
/opt/homebrew/Cellar/udunits/2.2.28/INSTALL_RECEIPT.json
/opt/homebrew/Cellar/udunits/2.2.28/bin
/opt/homebrew/Cellar/udunits/2.2.28/bin/udunits2
/opt/homebrew/Cellar/udunits/2.2.28/.brew
/opt/homebrew/Cellar/udunits/2.2.28/.brew/udunits.rb
/opt/homebrew/Cellar/udunits/2.2.28/include
/opt/homebrew/Cellar/udunits/2.2.28/include/udunits.h
/opt/homebrew/Cellar/udunits/2.2.28/include/converter.h
/opt/homebrew/Cellar/udunits/2.2.28/include/udunits2.h
/opt/homebrew/Cellar/udunits/2.2.28/sbom.spdx.json
/opt/homebrew/Cellar/udunits/2.2.28/README
/opt/homebrew/Cellar/udunits/2.2.28/lib
/opt/homebrew/Cellar/udunits/2.2.28/lib/libudunits2.0.dylib
/opt/homebrew/Cellar/udunits/2.2.28/lib/libudunits2.a
/opt/homebrew/Cellar/udunits/2.2.28/lib/libudunits2.dylib
/opt/homebrew/Cellar/udunits/2.2.28/COPYRIGHT
/opt/homebrew/Cellar/udunits/2.2.28/share
/opt/homebrew/Cellar/udunits/2.2.28/share/info
/opt/homebrew/Cellar/udunits/2.2.28/share/info/udunits2.info
/opt/homebrew/Cellar/udunits/2.2.28/share/info/udunits2prog.info
/opt/homebrew/Cellar/udunits/2.2.28/share/info/udunits2lib.info
/opt/homebrew/Cellar/udunits/2.2.28/share/doc
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits/udunits2-prefixes.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits/udunits2.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits/CHANGE_LOG
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits/README
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits/udunits2-common.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits/udunits2-derived.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits/COPYRIGHT
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits/udunits2-accepted.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/doc/udunits/udunits2-base.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/udunits
/opt/homebrew/Cellar/udunits/2.2.28/share/udunits/udunits2-prefixes.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/udunits/udunits2.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/udunits/udunits2-common.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/udunits/udunits2-derived.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/udunits/udunits2-accepted.xml
/opt/homebrew/Cellar/udunits/2.2.28/share/udunits/udunits2-base.xml
/opt/homebrew/share/info/udunits2.info
/opt/homebrew/share/info/udunits2prog.info
/opt/homebrew/share/info/udunits2lib.info
/opt/homebrew/share/doc/udunits
/opt/homebrew/share/udunits

[t-kalinowski]

For others that run into the issue, one simple fix is to set the env vars (possibly in .Renviron if you're iterating on the dev version of the package):

UDUNITS2_LIBS='/opt/homebrew/lib/' UDUNITS2_INCLUDE='/opt/homebrew/include/' Rscript -e 'remotes::install_local()'

However, I think {units} should find these locations automatically. Since the x86->arm transition, this is the new default homebrew install location.

[Enchufa2]

This is useful, thanks! I wondered why package checks with r-lib/actions started to fail on macOS, because we don't do anything special to find Homebrew. So I suppose that it was in some standard location before (like /usr/local/include), and now it's in /opt, right? Not being a macOS user myself, I only came up with this workaround, but your solution is much more general, so I think that I can add something to the configure script to account for this.

[t-kalinowski]

I think the most portable way to get the homebrew prefix would be to use brew --prefix (or the corresponding envvar, if it has been set). For example:

UDUNITS2_LIBS=$(brew --prefix)/lib/
UDUNITS2_INCLUDE=$(brew --prefix)/include/

That said, I expect most users use the default location, and hardcoding /opt/homebrew/ in the search path on macOS should be fine.

[Enchufa2]

Could you please check if the brew branch solves this issue?

[t-kalinowski]

It works! It installed without any special config needed. 🎉