1 files changed, 59 insertions, 0 deletions
diff --git a/db/post_migrate/20210713042000_fix_ci_sources_pipelines_index_names.rb b/db/post_migrate/20210713042000_fix_ci_sources_pipelines_index_names.rb
new file mode 100644
index 00000000000..34701d8ba46
--- /dev/null
+++ b/db/post_migrate/20210713042000_fix_ci_sources_pipelines_index_names.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+# When the `ci_sources_pipelines` table was first introduced in GitLab
+# 9.3 EE, the foreign key names generate for the table appeared to
+# have been calculated via a hash using the table name
+# `ci_pipeline_source_pipelines`. This led to a merge conflict and
+# confusion during a CE to EE merge in GitLab 10.0, which regenerated
+# the schema with the correct foreign key names.
+#
+# Hence anyone who installed GitLab prior to 10.0 may have been seeded
+# the database with stale, incorrect foreign key names.
+#
+# During the Great BigInt Conversion of 2021, several migrations
+# assumed that the foreign key `fk_be5624bf37` existed for
+# `ci_sources_pipeline`. However, older installations may have had the
+# correct foreign key under the name `fk_3f0c88d7dc`.
+#
+# To eliminate future confusion and migration failures, we now rename
+# the foreign key constraints and index to what they should be today.
+class FixCiSourcesPipelinesIndexNames < ActiveRecord::Migration[6.1]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  TABLE_NAME = 'ci_sources_pipelines'
+
+  # GitLab 9.5.4: https://gitlab.com/gitlab-org/gitlab/-/blob/v9.5.4-ee/db/schema.rb#L2026-2030
+  # GitLab 10.0: https://gitlab.com/gitlab-org/gitlab/-/blob/v10.0.0-ee/db/schema.rb#L2064-2068
+  OLD_TO_NEW_FOREIGN_KEY_DEFS = {
+    'fk_3f0c88d7dc' => { table: :ci_builds, column: :source_job_id, name: 'fk_be5624bf37' },
+    'fk_b8c0fac459' => { table: :ci_pipelines, column: :pipeline_id, name: 'fk_e1bad85861' },
+    'fk_3a3e3cb83a' => { table: :ci_pipelines, column: :source_pipeline_id, name: 'fk_d4e29af7d7' },
+    'fk_8868d0f3e4' => { table: :projects, column: :source_project_id, name: 'fk_acd9737679' },
+    'fk_83b4346e48' => { table: :projects, name: 'fk_1e53c97c0a' }
+  }
+  OLD_INDEX_NAME = 'index_ci_pipeline_source_pipelines_on_source_job_id'
+  NEW_INDEX_NAME = 'index_ci_sources_pipelines_on_source_job_id'
+
+  def up
+    OLD_TO_NEW_FOREIGN_KEY_DEFS.each do |old_name, entry|
+      options = { column: entry[:column], name: old_name }.compact
+
+      if foreign_key_exists?(TABLE_NAME, entry[:table], **options)
+        rename_constraint(TABLE_NAME, old_name, entry[:name])
+      end
+    end
+
+    if index_exists_by_name?(TABLE_NAME, OLD_INDEX_NAME)
+      if index_exists_by_name?(TABLE_NAME, NEW_INDEX_NAME)
+        remove_concurrent_index_by_name(TABLE_NAME, OLD_INDEX_NAME)
+      else
+        rename_index(TABLE_NAME, OLD_INDEX_NAME, NEW_INDEX_NAME)
+      end
+    end
+  end
+
+  # There's no reason to revert this change since it should apply on stale schemas
+  def down; end
+end