Fix rake db:structure:dump on Postgres when multiple schemas are used.

If postgresql is being used and there are multiple schemas listed on the
`schema_search_path`, then `structure.sql` dumps (triggered by `rake
db:structure:dump` or `config.active_record.schema_format = :sql`) began
failing in Rails 4.2.5.

This is due to the changes made in
https://github.com/rails/rails/pull/17885 The problem is that multiple
schemas were getting getting passed to `Kernel.system` as a single,
space delimited string argument (for example, "--schema=foo
--schema=bar"). However, with the updated array style of calling
`Kernel.system`, these need to be passed as separate arguments (for
example, "--schema=foo", "--schema=bar"). If they get passed as a single
string, then the underlying pg_dump program isn't sure how to interpret
that single argument and you'll get an error reporting: "pg_dump: No
matching schemas were found"

1 files changed, 2 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
index cd7d949239..8b4874044c 100644
--- a/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
@@ -56,9 +56,9 @@ module ActiveRecord
 
         args = ['-s', '-x', '-O', '-f', filename]
         unless search_path.blank?
-          args << search_path.split(',').map do |part|
+          args += search_path.split(',').map do |part|
             "--schema=#{part.strip}"
-          end.join(' ')
+          end
         end
         args << configuration['database']
         run_cmd('pg_dump', args, 'dumping')