Add table for merge request commits

This is an ID-less table with just three columns: an association to the merge
request diff the commit belongs to, the relative order of the commit within the
merge request diff, and the commit SHA itself.

Previously we stored much more information about the commits, so that we could
display them even when they were deleted from the repo. Since 8.0, we ensure
that those commits are kept around for as long as the target repo itself is, so
we don't need to duplicate that data in the database.

2 files changed, 36 insertions, 0 deletions

diff --git a/db/migrate/20170616133147_create_merge_request_diff_commits.rb b/db/migrate/20170616133147_create_merge_request_diff_commits.rb
new file mode 100644
index 00000000000..616464cb470
--- /dev/null
+++ b/db/migrate/20170616133147_create_merge_request_diff_commits.rb
@@ -0,0 +1,20 @@
+class CreateMergeRequestDiffCommits < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def change
+    create_table :merge_request_diff_commits, id: false do |t|
+      t.datetime_with_timezone :authored_date
+      t.datetime_with_timezone :committed_date
+      t.belongs_to :merge_request_diff, null: false, foreign_key: { on_delete: :cascade }
+      t.integer :relative_order, null: false
+      t.binary :sha, null: false, limit: 20
+      t.text :author_name
+      t.text :author_email
+      t.text :committer_name
+      t.text :committer_email
+      t.text :message
+
+      t.index [:merge_request_diff_id, :relative_order], name: 'index_merge_request_diff_commits_on_mr_diff_id_and_order', unique: true
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index f12fdf903c5..a47a6ae9a98 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -693,6 +693,21 @@ ActiveRecord::Schema.define(version: 20170703102400) do
   add_index "members", ["source_id", "source_type"], name: "index_members_on_source_id_and_source_type", using: :btree
   add_index "members", ["user_id"], name: "index_members_on_user_id", using: :btree
 
+  create_table "merge_request_diff_commits", id: false, force: :cascade do |t|
+    t.datetime "authored_date"
+    t.datetime "committed_date"
+    t.integer "merge_request_diff_id", null: false
+    t.integer "relative_order", null: false
+    t.binary "sha", null: false
+    t.text "author_name"
+    t.text "author_email"
+    t.text "committer_name"
+    t.text "committer_email"
+    t.text "message"
+  end
+
+  add_index "merge_request_diff_commits", ["merge_request_diff_id", "relative_order"], name: "index_merge_request_diff_commits_on_mr_diff_id_and_order", unique: true, using: :btree
+
   create_table "merge_request_diff_files", id: false, force: :cascade do |t|
     t.integer "merge_request_diff_id", null: false
     t.integer "relative_order", null: false
@@ -1563,6 +1578,7 @@ ActiveRecord::Schema.define(version: 20170703102400) do
   add_foreign_key "labels", "projects", name: "fk_7de4989a69", on_delete: :cascade
   add_foreign_key "lists", "boards", name: "fk_0d3f677137", on_delete: :cascade
   add_foreign_key "lists", "labels", name: "fk_7a5553d60f", on_delete: :cascade
+  add_foreign_key "merge_request_diff_commits", "merge_request_diffs", on_delete: :cascade
   add_foreign_key "merge_request_diff_files", "merge_request_diffs", on_delete: :cascade
   add_foreign_key "merge_request_diffs", "merge_requests", name: "fk_8483f3258f", on_delete: :cascade
   add_foreign_key "merge_request_metrics", "ci_pipelines", column: "pipeline_id", on_delete: :cascade