Backport gitlab-rails backup script improvement

config/patches/gitlab-rails/backup_read_REVISION.patch

-diff --git a/lib/backup/manager.rb b/lib/backup/manager.rb
-index efaefa4..8f0e38f 100644
---- a/lib/backup/manager.rb
-+++ b/lib/backup/manager.rb
-@@ -7,7 +7,7 @@ module Backup
-       s = {}
-       s[:db_version]         = "#{ActiveRecord::Migrator.current_version}"
-       s[:backup_created_at]  = Time.now
--      s[:gitlab_version]     = %x{git rev-parse HEAD}.gsub(/\n/,"")
-+      s[:gitlab_version]     = File.read(Rails.root.join('REVISION')).chomp
-       s[:tar_version]        = %x{tar --version | head -1}.gsub(/\n/,"")
- 
-       Dir.chdir(Gitlab.config.backup.path)
-@@ -92,7 +92,7 @@ module Backup
-         Dir.chdir(Rails.root)
- 
-         # restoring mismatching backups can lead to unexpected problems
--        if settings[:gitlab_version] != %x{git rev-parse HEAD}.gsub(/\n/, "")
-+        if settings[:gitlab_version] != File.read(Rails.root.join('REVISION')).chomp
-           puts "GitLab version mismatch:".red
-           puts "  Your current HEAD differs from the HEAD in the backup!".red
-           puts "  Please switch to the following revision and try again:".red

config/patches/gitlab-rails/backup_use_VERSION.patch

+diff --git a/lib/backup/manager.rb b/lib/backup/manager.rb
+index efaefa4..a93d35a 100644
+--- a/lib/backup/manager.rb
++++ b/lib/backup/manager.rb
+@@ -7,7 +7,7 @@ module Backup
+       s = {}
+       s[:db_version]         = "#{ActiveRecord::Migrator.current_version}"
+       s[:backup_created_at]  = Time.now
+-      s[:gitlab_version]     = %x{git rev-parse HEAD}.gsub(/\n/,"")
++      s[:gitlab_version]     = Gitlab::VERSION
+       s[:tar_version]        = %x{tar --version | head -1}.gsub(/\n/,"")
+ 
+       Dir.chdir(Gitlab.config.backup.path)
+@@ -87,21 +87,15 @@ module Backup
+       settings = YAML.load_file("backup_information.yml")
+       ENV["VERSION"] = "#{settings[:db_version]}" if settings[:db_version].to_i > 0
+ 
+-      # backups directory is not always sub of Rails root and able to execute the git rev-parse below
+-      begin
+-        Dir.chdir(Rails.root)
+-
+-        # restoring mismatching backups can lead to unexpected problems
+-        if settings[:gitlab_version] != %x{git rev-parse HEAD}.gsub(/\n/, "")
+-          puts "GitLab version mismatch:".red
+-          puts "  Your current HEAD differs from the HEAD in the backup!".red
+-          puts "  Please switch to the following revision and try again:".red
+-          puts "  revision: #{settings[:gitlab_version]}".red
+-          exit 1
+-        end
+-      ensure
+-        # chdir back to original intended dir
+-        Dir.chdir(Gitlab.config.backup.path)
++      # restoring mismatching backups can lead to unexpected problems
++      if settings[:gitlab_version] != Gitlab::VERSION
++        puts "GitLab version mismatch:".red
++        puts "  Your current GitLab version (#{Gitlab::VERSION}) differs from the GitLab version in the backup!".red
++        puts "  Please switch to the following version and try again:".red
++        puts "  version: #{settings[:gitlab_version]}".red
++        puts
++        puts "Hint: git checkout v#{settings[:gitlab_version]}"
++        exit 1
+       end
+     end
+   end

config/software/gitlab-rails.rb

@@ -43,8 +43,10 @@ build do
   # source code to include the Git revision of the code included in the omnibus
   # build.
   command "sed -i \"s/.*REVISION.*/REVISION = '$(git log --pretty=format:'%h' -n 1)'/\" config/initializers/2_app.rb"
-  patch :source => "backup_read_REVISION.patch"
-  command "git rev-parse HEAD > REVISION"
+
+  # gitlab-rails master has improved the versioning logic for backups. The old
+  # solution is painful for omnibus-gitlab so we are backporting the improvement.
+  patch :source => "backup_use_VERSION.patch"
   # The user uploads path is not (yet) configurable in gitlab-rails. As a
   # workaround, omnibus-gitlab creates a symlink for public/uploads. This breaks