6 files changed, 36 insertions, 1 deletions
diff --git a/app/models/ci/build.rb b/app/models/ci/build.rb
index b8a76e662b0..c9b5231e791 100644
--- a/app/models/ci/build.rb
+++ b/app/models/ci/build.rb
@@ -548,7 +548,7 @@ module Ci
     end
 
     def has_old_trace?
-      old_trace.present?
+      project.legacy_traces_enabled? && old_trace.present?
     end
 
     def trace=(data)
@@ -556,6 +556,8 @@ module Ci
     end
 
     def old_trace
+      return unless project.legacy_traces_enabled?
+
       read_attribute(:trace)
     end
 
diff --git a/app/models/project.rb b/app/models/project.rb
index e2869fc2ad5..ba21d4969eb 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -2139,6 +2139,10 @@ class Project < ApplicationRecord
     pool_repository.present?
   end
 
+  def legacy_traces_enabled?
+    Feature.enabled?(:ci_enable_legacy_traces, self)
+  end
+
   private
 
   def merge_requests_allowing_collaboration(source_branch = nil)
diff --git a/changelogs/unreleased/disable-support-for-legacy-traces.yml b/changelogs/unreleased/disable-support-for-legacy-traces.yml
new file mode 100644
index 00000000000..2e54b70225f
--- /dev/null
+++ b/changelogs/unreleased/disable-support-for-legacy-traces.yml
@@ -0,0 +1,5 @@
+---
+title: Disable support for legacy traces
+merge_request: 26848
+author:
+type: deprecated
diff --git a/doc/administration/job_traces.md b/doc/administration/job_traces.md
index 63945506f3c..7d66323346f 100644
--- a/doc/administration/job_traces.md
+++ b/doc/administration/job_traces.md
@@ -86,6 +86,10 @@ To archive those legacy job traces, please follow the instruction below.
 
     If the count becomes zero, the archiving processes are done
 
+NOTE: **NOTE** As of GitLab 11.10, those legacy traces are deprecated and will be
+removed in the next major version update. You can preserve those legacy traces by enabling a feature flag
+`Feature.enable(:ci_enable_legacy_traces)` and archiving it according to the above steps.
+
 ## How to migrate archived job traces to object storage
 
 > [Introduced][ce-21193] in GitLab 11.3.
diff --git a/lib/gitlab/ci/trace.rb b/lib/gitlab/ci/trace.rb
index bf5f2a31f0e..e52e1e01fcc 100644
--- a/lib/gitlab/ci/trace.rb
+++ b/lib/gitlab/ci/trace.rb
@@ -228,6 +228,8 @@ module Gitlab
       end
 
       def deprecated_path
+        return unless job.project.legacy_traces_enabled?
+
         File.join(
           Settings.gitlab_ci.builds_path,
           job.created_at.utc.strftime("%Y_%m"),
diff --git a/spec/models/ci/build_spec.rb b/spec/models/ci/build_spec.rb
index 697fe3fda06..2a1872dd7d8 100644
--- a/spec/models/ci/build_spec.rb
+++ b/spec/models/ci/build_spec.rb
@@ -776,6 +776,14 @@ describe Ci::Build do
       end
 
       it { is_expected.to be_truthy }
+
+      context 'when ci_enable_legacy_traces feature flag is disabled' do
+        before do
+          stub_feature_flags(ci_enable_legacy_traces: false)
+        end
+
+        it { is_expected.to be_falsy }
+      end
     end
 
     context 'when old trace does not exist' do
@@ -799,6 +807,16 @@ describe Ci::Build do
     it "expect to receive data from database" do
       is_expected.to eq('old trace')
     end
+
+    context 'when ci_enable_legacy_traces feature flag is disabled' do
+      before do
+        stub_feature_flags(ci_enable_legacy_traces: false)
+      end
+
+      it 'does not return old trace' do
+        is_expected.to be_nil
+      end
+    end
   end
 
   describe '#erase_old_trace!' do