Merge pull request #431 from sodabrew/with_dirconfig

Handle dir_config and with_config mysql more strictly, add rpath more often

Author: sodabrew

README.md

@@ -22,7 +22,27 @@ gem install mysql2
 
 This gem links against MySQL's `libmysqlclient` C shared library. You may need to install a package such as `libmysqlclient-dev`, `mysql-devel`, or other appropriate package for your system.
 
-If you have installed MySQL to a non-standard location, add `gem install mysql2 --with-mysql-config=/some/random/path/bin/mysql_config`
+By default, the mysql2 gem will try to find a copy of MySQL in this order:
+
+* Option `--with-mysql-dir`, if provided (see below).
+* Option `--with-mysql-config`, if provided (see below).
+* Several typical paths for `msyql_config` (default for the majority of users).
+* The directory `/usr/local`.
+
+### Configuration options
+
+Use these options by `gem install mysql2 -- [--optionA] [--optionB=argument]`.
+The following options are mutually exclusive.
+
+* `--with-mysql-dir[=/path/to/mysqldir]` -
+Specify the directory where MySQL is installed. The mysql2 gem will not use
+`mysql_config`, but will instead look at `mysqldir/lib` and `mysqldir/include`
+for the library and header files.
+
+* `--with-mysql-config[=/path/to/mysql_config]` -
+Specify a path to the `mysql_config` binary provided by your copy of MySQL. The
+mysql2 gem will ask this `mysql_config` binary about the compiler and linker
+arguments needed.
 
 ### Windows
 First, make sure you have the DevKit installed (http://rubyinstaller.org/downloads/) and its variables

ext/mysql2/extconf.rb

@@ -31,19 +31,27 @@ def asplode lib
 
 GLOB = "{#{dirs.join(',')}}/{mysql_config,mysql_config5}"
 
-if RUBY_PLATFORM =~ /mswin|mingw/
-  inc, lib = dir_config('mysql')
-
+# If the user has provided a --with-mysql-dir argument, we must respect it or fail.
+inc, lib = dir_config('mysql')
+if inc && lib
   # Ruby versions not incorporating the mkmf fix at
   # https://bugs.ruby-lang.org/projects/ruby-trunk/repository/revisions/39717
   # do not properly search for lib directories, and must be corrected
   unless lib && lib[-3, 3] == 'lib'
     @libdir_basename = 'lib'
     inc, lib = dir_config('mysql')
   end
-  exit 1 unless have_library("libmysql")
-elsif mc = (with_config('mysql-config') || Dir[GLOB].first) then
+  abort "-----\nCannot find include dir at #{inc}\n-----" unless inc && File.directory?(inc)
+  abort "-----\nCannot find library dir at #{lib}\n-----" unless lib && File.directory?(lib)
+  warn  "-----\nUsing --with-mysql-dir=#{File.dirname inc}\n-----"
+  rpath_dir = lib
+elsif mc = (with_config('mysql-config') || Dir[GLOB].first)
+  # If the user has provided a --with-mysql-config argument, we must respect it or fail.
+  # If the user gave --with-mysql-config with no argument means we should try to find it.
   mc = Dir[GLOB].first if mc == true
+  abort "-----\nCannot find mysql_config at #{mc}\n-----" unless mc && File.exists?(mc)
+  abort "-----\nCannot execute mysql_config at #{mc}\n-----" unless File.executable?(mc)
+  warn  "-----\nUsing mysql_config at #{mc}\n-----"
   ver = `#{mc} --version`.chomp.to_f
   includes = `#{mc} --include`.chomp
   exit 1 if $? != 0
@@ -55,18 +63,24 @@ def asplode lib
   exit 1 if $? != 0
   $INCFLAGS += ' ' + includes
   $libs = libs + " " + $libs
+  rpath_dir = libs
 else
   inc, lib = dir_config('mysql', '/usr/local')
   libs = ['m', 'z', 'socket', 'nsl', 'mygcc']
   while not find_library('mysqlclient', 'mysql_query', lib, "#{lib}/mysql") do
     exit 1 if libs.empty?
     have_library(libs.shift)
   end
+  rpath_dir = lib
+end
+
+if RUBY_PLATFORM =~ /mswin|mingw/
+  exit 1 unless have_library('libmysql')
 end
 
-if have_header('mysql.h') then
+if have_header('mysql.h')
   prefix = nil
-elsif have_header('mysql/mysql.h') then
+elsif have_header('mysql/mysql.h')
   prefix = 'mysql'
 else
   asplode 'mysql.h'
@@ -77,17 +91,27 @@ def asplode lib
   asplode h unless have_header h
 end
 
-# GCC specific flags
-if RbConfig::MAKEFILE_CONFIG['CC'] =~ /gcc/
-  $CFLAGS << ' -Wall -funroll-loops'
+# These gcc style flags are also supported by clang and xcode compilers,
+# so we'll use a does-it-work test instead of an is-it-gcc test.
+gcc_flags = ' -Wall -funroll-loops'
+if try_link('int main() {return 0;}', gcc_flags)
+  $CFLAGS << gcc_flags
+end
 
-  if libdir = $libs[%r{-L(/[^ ]+)}, 1]
-    # The following comment and test is borrowed from the Pg gem:
-    # Try to use runtime path linker option, even if RbConfig doesn't know about it.
-    # The rpath option is usually set implicit by dir_config(), but so far not on Mac OS X.
-    if RbConfig::CONFIG["RPATHFLAG"].to_s.empty? && try_link('int main() {return 0;}', " -Wl,-rpath,#{libdir}")
-      $LDFLAGS << " -Wl,-rpath,#{libdir}"
+if libdir = rpath_dir[%r{(-L)?(/[^ ]+)}, 2]
+  rpath_flags = " -Wl,-rpath,#{libdir}"
+  if RbConfig::CONFIG["RPATHFLAG"].to_s.empty? && try_link('int main() {return 0;}', rpath_flags)
+    # Usually Ruby sets RPATHFLAG the right way for each system, but not on OS X.
+    warn "-----\nSetting rpath to #{libdir}\n-----"
+    $LDFLAGS << rpath_flags
+  else
+    if RbConfig::CONFIG["RPATHFLAG"].to_s.empty?
+      # If we got here because try_link failed, warn the user
+      warn "-----\nDon't know how to set rpath on your system, if MySQL libraries are not in path mysql2 may not load\n-----"
     end
+    # Make sure that LIBPATH gets set if we didn't explicitly set the rpath.
+    warn "-----\nSetting libpath to #{libdir}\n-----"
+    $LIBPATH << libdir unless $LIBPATH.include?(libdir)
   end
 end