I am trying to install mysql2 (version 0.4.5) and I am using Rails 5.0.2, Ruby 2.3.1
I've already installed mysql server using homebrew (version 8.0.11)and started mysql as:
brew install mysql
brew services start mysql
Gemfile.rb
gem 'mysql2'
When I try installing gem mysql2 I am getting the following error
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
current directory: /Users/gomathi/.rvm/gems/ruby-2.3.1@connector/gems/mysql2-0.4.5/ext/mysql2
creating Makefile
current directory: /Users/gomathi/.rvm/gems/ruby-2.3.1@connector/gems/mysql2-0.4.5/ext/mysql2
make "DESTDIR=" clean
current directory: /Users/gomathi/.rvm/gems/ruby-2.3.1@connector/gems/mysql2-0.4.5/ext/mysql2
make "DESTDIR="
compiling client.c
In file included from client.c:1:
In file included from ./mysql2_ext.h:41:
./result.h:24:3: error: unknown type name 'my_bool'
my_bool *is_null;
^
./result.h:25:3: error: unknown type name 'my_bool'
my_bool *error;
^
client.c:507:3: error: use of undeclared identifier 'my_bool'
my_bool res = mysql_read_query_result(client);
^
client.c:509:19: error: use of undeclared identifier 'res'
return (void *)(res == 0 ? Qtrue : Qfalse);
^
client.c:828:3: error: use of undeclared identifier 'my_bool'
my_bool boolval;
^
client.c:859:7: error: use of undeclared identifier 'boolval'
boolval = (value == Qfalse ? 0 : 1);
^
client.c:860:17: error: use of undeclared identifier 'boolval'
retval = &boolval;
^
client.c:863:10: 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/8.0.11/include/mysql/mysql.h:188:3: note: 'MYSQL_DEFAULT_AUTH' declared here
MYSQL_DEFAULT_AUTH,
^
client.c:864:7: error: use of undeclared identifier 'boolval'
boolval = (value == Qfalse ? 0 : 1);
^
client.c:865:17: error: use of undeclared identifier 'boolval'
retval = &boolval;
^
client.c:896:38: error: use of undeclared identifier 'boolval'
wrapper->reconnect_enabled = boolval;
^
client.c:1285:38: 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/8.0.11/include/mysql/mysql.h:188:3: note: 'MYSQL_DEFAULT_AUTH' declared here
MYSQL_DEFAULT_AUTH,
^
12 errors generated.
make: *** [client.o] Error 1
make failed, exit code 2
How can I get the job done?.
You're installing an older version of the gem (0.4.5). I had the same issue (using 0.4.3). Installing version 0.4.10 solved this for me.
Try this:
gem install mysql2 -v 0.4.10
If that installs cleanly, you'll have to update your Gemfile to require this version:
gem 'mysql2', '~> 0.4.10'
Don't install a newer version of the gem (i.e. 0.5.x), they won't work with Rails 4 or older releases of Rails 5 (before 5.0.7/5.1.6) (see https://github.com/brianmario/mysql2/issues/950).
According to MySQL 5.7 document MYSQL_SECURE_AUTH has been enabled by default in 5.7, because of that the mysql2 not compile below the version 0.4.10 to the MySQL => 5.7
Another alternative that worked for me here was to install MariaDB, that too specifically version 10.0.x
$ brew install mariadb@10.0
$ brew link mariadb@10.0 --force
To auto-start MariaDB Server, use Homebrew's services functionality, which integrates with macOS launchctl:
brew services start mariadb@10.0
Now, the installation of mysql2 will work like a charm.
$ gem install mysql2 -v '0.4.6'
Building native extensions. This could take a while...
Successfully installed mysql2-0.4.6
I made it work by installing MySQL from dmg package https://dev.mysql.com/downloads/mysql/5.7.html#downloads
I think you can remove everything in Gemfile.lock. After try bundle install again and your Project will be running ok.
Try to unlink and reinstall mysql:
brew unlink mysql
brew cleanup
brew install mysql
gem install mysql2
来源：https://stackoverflow.com/questions/50909928/installing-mysql-2-gem-fails