ARM64 architecture (M1 chip): Cannot install pg gem (using PostgresApp)

Question

I've been trying to install a rails project on my computer (Macbook Pro 2020 with M1) running Big Sur.

I have the PostgresApp installed.

When running bundle install it fails to build the pg gem so I tried to install the gem manually (by doing gem install pg - tried also with gem install pg -- --with-pg-config=/Applications/Postgres.app/Contents/Versions/10/bin/pg_config).

I get an error saying:

ERROR:  Error installing pg:
ERROR: Failed to build gem native extension.

Can't find the PostgreSQL client library (libpq)
*** extconf.rb failed ***

When checking the error logs I see:

have_library: checking for PQconnectdb() in -lpq... -------------------- no

ld: warning: ignoring file /Applications/Postgres.app/Contents/Versions/13/lib/libpq.dylib, building for macOS-arm64 but attempting to link with file built for macOS-x86_64
Undefined symbols for architecture arm64:
  "_PQconnectdb", referenced from:
      _t in conftest-db479f.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
checked program was:
/* begin */
 1: #include "ruby.h"
 2:
 3: #include <libpq-fe.h>
 4:
 5: /*top*/
 6: extern int t(void);
 7: int main(int argc, char **argv)
 8: {
 9:   if (argc > 1000000) {
10:     printf("%p", &t);
11:   }
12:
13:   return 0;
14: }
15: int t(void) { void ((*volatile p)()); p = (void ((*)()))PQconnectdb; return !p; }
/* end */

Any idea how to solve this?

Answer 1

For those who are just trying to install the pg gem and don't care about PostgresApp, the key to fixing pg on the M1 is ensuring the existence of the libpq. These steps allowed me to get the pg gem install on my M1 mac without resorting to using x86 version or build flags:

brew install libpq
export PATH="/opt/homebrew/opt/libpq/bin:$PATH"
gem install pg

Answer 2

I ran into the same problem with M1 + the ruby pg gem. The problem was that I had a mix of ARM + x86 binaries on my system, and pg apparently can only be compiled with x86 at present. As FYI, there are new issues reported in its github repo, so hopefully it'll be solved soon here

My work around:

0. uninstall ARM based homebrew + rbenv and remove your .gem + .rbenv directories from your home dir (homebrew uninstall instructions)

1. re-install homebrew as x86 intel-based

$ arch -x86_64 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

2. install rbenv as x86 (or whatever your preferred ruby version manager)

$ arch -x86_64 brew install rbenv
$ arch -x86_64 rbenv install 2.7.2

3a) (optional) for postgres.app, you can pre-configure where pg-config lives so you don't have to run the manual gem install when it chokes. eg

$ bundle config build.pg --with-pg-config=/Applications/Postgres.app/Contents/Versions/latest/bin/pg_config

3b) (optional) for brew, you can do the same:

$ bundle config build.pg --with-pg-config=$(brew --prefix)/opt/libpq/bin/pg_config

4. re-bundle your project and enjoy ruby on rosetta 2 (for now)

$ bundle install
$ rails s

Answer 3

Encountered the same issue with brew PostgreSQL, but I installed pg gem successfully with Ruby 2.7 on macOS M1(12 Monterey), I have both x86 and arm64 brew installed. Since pg must be compiled with x86 libpq, so I installed libpq with x86 brew

❯ which brow
brow: aliased to arch --x86_64 /usr/local/Homebrew/bin/brew

❯ brow install libpq

❯ brew install PostgreSQL # Install arm64 PostgreSQL 
❯ brew services start postgresql
❯ ps -ef | grep postgresql
  501 23655     1   0  2:29PM ??         0:00.10 /opt/homebrew/opt/postgresql/bin/postgres -D /opt/homebrew/var/postgres

❯ which brew
/opt/homebrew/bin/brew
❯ brew -v
Homebrew 3.3.2-50-geca16a2
Homebrew/homebrew-core (git revision ec99d74792c; last commit 2021-11-05)
Homebrew/homebrew-cask (git revision 2ab51af9c3; last commit 2021-11-05)

Then I can install the pg gem

❯ ruby -v
ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-darwin19]

❯ gem install pg -v 1.2.3 -- --with-pq-dir=/usr/local/Cellar/libpq/13.3
Building native extensions with: '--with-pq-dir=/usr/local/Cellar/libpq/13.3'
This could take a while...
Successfully installed pg-1.2.3
Parsing documentation for pg-1.2.3
Done installing documentation for pg after 0 seconds

But failed with Ruby 2.6, I don't know why

gem install pg -v 1.2.3 -- --with-pq-dir=/usr/local/Cellar/libpq/13.3
Building native extensions with: '--with-pq-dir=/usr/local/Cellar/libpq/13.3'
This could take a while...
ERROR:  Error installing pg:
    ERROR: Failed to build gem native extension.

    current directory: /Users/felix/.rvm/gems/ruby-2.6.6/gems/pg-1.2.3/ext
/Users/felix/.rvm/rubies/ruby-2.6.6/bin/ruby -I /Users/felix/.rvm/rubies/ruby-2.6.6/lib/ruby/site_ruby/2.6.0 -r ./siteconf20211105-41969-1oxcuyy.rb extconf.rb --with-pq-dir\=/usr/local/Cellar/libpq/13.3
checking for pg_config... yes
Using config values from /opt/homebrew/bin/pg_config
checking for libpq-fe.h... yes
checking for libpq/libpq-fs.h... yes
checking for pg_config_manual.h... yes
checking for PQconnectdb() in -lpq... no
checking for PQconnectdb() in -llibpq... no
checking for PQconnectdb() in -lms/libpq... no
Can't find the PostgreSQL client library (libpq)

Update 2021-11-06

Installed pg successfully with Ruby 2.6 too.

1. First install x86 postgresql

# build Postgresql from source, as 
# Error: postgresql: no bottle available! 
# You can try to install from source with:  
# brew install --build-from-source postgresql


brow install --build-from-source postgresql

2. Install pg gem with prefix

gem install pg -v 1.2.3 -- --with-pg_config=/usr/local/Cellar/postgresql/13.3/bin/pg_config --with-pq-dir=/usr/local/Cellar/libpq/13.3