Make sure that `gem install mysql2 -v '0.3.21'` succeeds before bundling

Question

I'm trying to bundle install a Rails 3.2 LTS app on my mac (High Sierra), but when it gets to the mysql2 gem it fails:

current directory: /Users/Daniel/.gem/ruby/2.3.5/gems/mysql2-0.3.21/ext/mysql2
/Users/Daniel/.rubies/ruby-2.3.5/bin/ruby -r ./siteconf20180828-30901-1g9qqrc.rb extconf.rb
checking for ruby/thread.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for rb_thread_blocking_region()... no
checking for rb_wait_for_single_fd()... yes
checking for rb_hash_dup()... yes
checking for rb_intern3()... yes
-----
Using mysql_config at /usr/local/bin/mysql_config
-----
checking for mysql.h... yes
checking for errmsg.h... yes
checking for mysqld_error.h... yes
-----
Setting rpath to /usr/local/Cellar/mysql/8.0.12/lib
-----
creating Makefile

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /Users/Daniel/.gem/ruby/2.3.5/extensions/x86_64-darwin-16/2.3.0-static/mysql2-0.3.21/mkmf.log

current directory: /Users/Daniel/.gem/ruby/2.3.5/gems/mysql2-0.3.21/ext/mysql2
make "DESTDIR=" clean

current directory: /Users/Daniel/.gem/ruby/2.3.5/gems/mysql2-0.3.21/ext/mysql2
make "DESTDIR="
compiling client.c
client.c:367:33: warning: implicit conversion loses integer precision: 'long' to 'unsigned int' [-Wshorten-64-to-32]
        elapsed_time = end_time - start_time;
                     ~ ~~~~~~~~~^~~~~~~~~~~~
client.c:439:3: error: use of undeclared identifier 'my_bool'
  my_bool res = mysql_read_query_result(client);
  ^
client.c:441:19: error: use of undeclared identifier 'res'
  return (void *)(res == 0 ? Qtrue : Qfalse);
                  ^
client.c:762:3: error: use of undeclared identifier 'my_bool'
  my_bool boolval;
  ^
client.c:793:7: error: use of undeclared identifier 'boolval'
      boolval = (value == Qfalse ? 0 : 1);
      ^
client.c:794:17: error: use of undeclared identifier 'boolval'
      retval = &boolval;
                ^
client.c:797:10: error: use of undeclared identifier 'MYSQL_SECURE_AUTH'; did you mean 'MYSQL_DEFAULT_AUTH'?
    case MYSQL_SECURE_AUTH:
         ^~~~~~~~~~~~~~~~~
         MYSQL_DEFAULT_AUTH
/usr/local/Cellar/mysql/8.0.12/include/mysql/mysql.h:188:3: note: 'MYSQL_DEFAULT_AUTH' declared here
  MYSQL_DEFAULT_AUTH,
  ^
client.c:798:7: error: use of undeclared identifier 'boolval'
      boolval = (value == Qfalse ? 0 : 1);
      ^
client.c:799:17: error: use of undeclared identifier 'boolval'
      retval = &boolval;
                ^
client.c:830:38: error: use of undeclared identifier 'boolval'
        wrapper->reconnect_enabled = boolval;
                                     ^
client.c:1152:56: warning: implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'unsigned int' [-Wshorten-64-to-32]
  mysql2rb = mysql2_mysql_enc_name_to_rb(charset_name, charset_name_len);
             ~~~~~~~~~~~~~~~~~~~~~~~~~~~               ^~~~~~~~~~~~~~~~
client.c:1185:38: error: use of undeclared identifier 'MYSQL_SECURE_AUTH'; did you mean 'MYSQL_DEFAULT_AUTH'?
  return _mysql_client_options(self, MYSQL_SECURE_AUTH, value);
                                     ^~~~~~~~~~~~~~~~~
                                     MYSQL_DEFAULT_AUTH
/usr/local/Cellar/mysql/8.0.12/include/mysql/mysql.h:188:3: note: 'MYSQL_DEFAULT_AUTH' declared here
  MYSQL_DEFAULT_AUTH,
  ^
2 warnings and 10 errors generated.
make: *** [client.o] Error 1

make failed, exit code 2

I've tried all the other tricks associated with fixing issues like this, but none of them have worked, which is why I'm posting here.

UPDATE:

I think I know what the problem is - I'm running mysql 8 on my machine, but the mysql2 0.3 gem isn't compatible with this - so I think a new question is required - how can I install both mysql 5.* and mysql8, and have each of them with with the relevant versions of the mysql2 gem?

Do I even need to use 8, or can I get away with just using 5.7?

Answer 1

You've probably found the answer to this by now but incase not (or incase I forget and need to Google this again), here is what worked for me:

gem install mysql2 -v '0.3.21' -- --with-opt-dir="$(brew --prefix openssl)"

I am using Rails 4.2.11 and MySQL server version 5.7.24 (installed via Homebrew)