Redmine

I found that the following change fixes the warning.

diff --git a/app/models/repository/bazaar.rb b/app/models/repository/bazaar.rb
index 8b07db34d..f7ad5b62c 100644
--- a/app/models/repository/bazaar.rb
+++ b/app/models/repository/bazaar.rb
@@ -17,7 +17,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

-require 'redmine/scm/adapters/bazaar_adapter'
+# require 'redmine/scm/adapters/bazaar_adapter'

 class Repository::Bazaar < Repository
   validates_presence_of :url, :log_encoding
diff --git a/app/models/repository/cvs.rb b/app/models/repository/cvs.rb
index e823275e4..03d57549d 100644
--- a/app/models/repository/cvs.rb
+++ b/app/models/repository/cvs.rb
@@ -17,7 +17,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

-require 'redmine/scm/adapters/cvs_adapter'
+# require 'redmine/scm/adapters/cvs_adapter'
 require 'digest/sha1'

 class Repository::Cvs < Repository
diff --git a/app/models/repository/filesystem.rb b/app/models/repository/filesystem.rb
index 5d823b9f4..51a93dfa1 100644
--- a/app/models/repository/filesystem.rb
+++ b/app/models/repository/filesystem.rb
@@ -20,7 +20,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

-require 'redmine/scm/adapters/filesystem_adapter'
+# require 'redmine/scm/adapters/filesystem_adapter'

 class Repository::Filesystem < Repository
   validates_presence_of :url
diff --git a/app/models/repository/git.rb b/app/models/repository/git.rb
index 839a26676..b367fe06e 100644
--- a/app/models/repository/git.rb
+++ b/app/models/repository/git.rb
@@ -18,7 +18,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

-require 'redmine/scm/adapters/git_adapter'
+# require 'redmine/scm/adapters/git_adapter'

 class Repository::Git < Repository
   validates_presence_of :url
diff --git a/app/models/repository/mercurial.rb b/app/models/repository/mercurial.rb
index 69f7bebdc..ac2921ccc 100644
--- a/app/models/repository/mercurial.rb
+++ b/app/models/repository/mercurial.rb
@@ -17,7 +17,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

-require 'redmine/scm/adapters/mercurial_adapter'
+# require 'redmine/scm/adapters/mercurial_adapter'

 class Repository::Mercurial < Repository
   # sort changesets by revision number
diff --git a/app/models/repository/subversion.rb b/app/models/repository/subversion.rb
index 0f01f863f..8e7962cd5 100644
--- a/app/models/repository/subversion.rb
+++ b/app/models/repository/subversion.rb
@@ -17,7 +17,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

-require 'redmine/scm/adapters/subversion_adapter'
+# require 'redmine/scm/adapters/subversion_adapter'

 class Repository::Subversion < Repository
   validates_presence_of :url

The warning can be observed only when the current directory is a working copy of the Subversion repo. It means that you obtained the source code of Redmine using "svn" command.

It is caused by r17407. Reverting the change fixes the issue.

Here is a workaround.

diff --git a/lib/redmine/version.rb b/lib/redmine/version.rb
index 8272e29e4..2fe75c55e 100644
--- a/lib/redmine/version.rb
+++ b/lib/redmine/version.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true

 require 'rexml/document'
+require 'redmine/scm/adapters/subversion_adapter'

 module Redmine
   # @private

Calling Redmine::Scm::Adapters::SubversionAdapter.client_command before requiring redmine/scm/adapters/subversion_adapter in the development mode gets the warning.

$ bin/rails c
Loading development environment (Rails 5.2.3)
[1] pry(main)> Redmine::Scm::Adapters::SubversionAdapter.client_command
=> "/usr/local/bin/svn" 
[2] pry(main)> require 'redmine/scm/adapters/subversion_adapter'
/Users/maeda/redmines/redmine-trunk/lib/redmine/scm/adapters/subversion_adapter.rb:29: warning: already initialized constant Redmine::Scm::Adapters::SubversionAdapter::SVN_BIN
/Users/maeda/redmines/redmine-trunk/lib/redmine/scm/adapters/subversion_adapter.rb:29: warning: previous definition of SVN_BIN was here
=> true
[3] pry(main)>