From 7a698cdc7a9f86c8953710c2e6881815e3546b8c Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Mon, 24 Nov 2025 12:08:39 +0000
Subject: [PATCH 01/17] Trigger error only when sifekiq retries have been
 exhausted

---
 app/models/ci/pipeline_creation/requests.rb   | 15 ++++++++
 .../merge_requests/create_pipeline_service.rb |  2 +-
 .../merge_requests/create_pipeline_worker.rb  | 25 ++++++++++++-
 .../merge_requests/create_pipeline_service.rb |  6 ++++
 .../create_pipeline_worker_spec.rb            | 35 +++++++++++++++++++
 5 files changed, 81 insertions(+), 2 deletions(-)

diff --git a/app/models/ci/pipeline_creation/requests.rb b/app/models/ci/pipeline_creation/requests.rb
index a062a67daa2f38..5d1418180b9f31 100644
--- a/app/models/ci/pipeline_creation/requests.rb
+++ b/app/models/ci/pipeline_creation/requests.rb
@@ -97,6 +97,21 @@ def merge_request_key(merge_request)
           format(MERGE_REQUEST_REDIS_KEY, project_id: merge_request.project_id, mr_id: merge_request.id)
         end
 
+        # Extracts merge request ID from Redis key and returns the MergeRequest object
+        #
+        # @param key [String] Redis key in MERGE_REQUEST_REDIS_KEY format
+        # @return [MergeRequest, nil] The MergeRequest object or nil if not found
+        def merge_request_from_key(key)
+          match = key.match(/mrs:\{(?<mr_id>\d+)\}/)
+          return unless match
+
+          mr_id = match[:mr_id].to_i
+
+          MergeRequest.find(mr_id)
+        rescue ActiveRecord::RecordNotFound
+          nil
+        end
+
         def hset(request, status, pipeline_id: nil, error: nil)
           Gitlab::Redis::SharedState.with do |redis|
             redis.multi do |transaction|
diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index 6851924d651280..21951f22692398 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -102,7 +102,7 @@ def cannot_create_pipeline_error
 
       ::Ci::PipelineCreation::Requests.failed(params[:pipeline_creation_request], error_message)
 
-      ServiceResponse.error(message: error_message, payload: nil)
+      ServiceResponse.error(message: error_message, payload: nil, reason: :retriable_error)
     end
   end
 end
diff --git a/app/workers/merge_requests/create_pipeline_worker.rb b/app/workers/merge_requests/create_pipeline_worker.rb
index d2d10dedcb278b..ed6083da452d65 100644
--- a/app/workers/merge_requests/create_pipeline_worker.rb
+++ b/app/workers/merge_requests/create_pipeline_worker.rb
@@ -15,6 +15,20 @@ class CreatePipelineWorker
     worker_resource_boundary :cpu
     idempotent!
 
+    sidekiq_retries_exhausted do |job, _exception|
+      pipeline_creation_request = job['args'][3]&.dig('pipeline_creation_request')
+      next unless pipeline_creation_request
+
+      merge_request = ::Ci::PipelineCreation::Requests.merge_request_from_key(pipeline_creation_request&.dig('key'))
+
+      error_message = 'Cannot create a pipeline for this merge request after multiple retries.'
+      Gitlab::AppJsonLogger.info(
+        message: "pipeline_service sidekiq_retries_exhausted"
+      )
+      ::Ci::PipelineCreation::Requests.failed(pipeline_creation_request, error_message)
+      GraphqlTriggers.ci_pipeline_creation_requests_updated(merge_request)
+    end
+
     def perform(project_id, user_id, merge_request_id, params = {})
       Gitlab::QueryLimiting.disable!('https://gitlab.com/gitlab-org/gitlab/-/issues/464679')
 
@@ -32,7 +46,7 @@ def perform(project_id, user_id, merge_request_id, params = {})
       push_options = params.with_indifferent_access[:push_options]
       gitaly_context = params.with_indifferent_access[:gitaly_context]
 
-      MergeRequests::CreatePipelineService
+      result = MergeRequests::CreatePipelineService
         .new(
           project: project,
           current_user: user,
@@ -44,6 +58,15 @@ def perform(project_id, user_id, merge_request_id, params = {})
           }
         ).execute(merge_request)
 
+      # If the service returned a retriable error, raise to trigger Sidekiq retry
+      # The request will only be marked as FAILED when retries are exhausted (see sidekiq_retries_exhausted hook)
+      Gitlab::AppJsonLogger.info(
+        message: "pipeline_service error",
+        error: result.error?,
+        reason: result.reason
+      )
+      raise StandardError, result.message if result.error? && result.reason == :retriable_error
+
       merge_request.update_head_pipeline
 
       after_perform(merge_request)
diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index 8d3b3ce1f53af3..6c5a72e7fee358 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -21,6 +21,9 @@ def allowed?(merge_request)
       private
 
       def create_merged_result_pipeline_for(merge_request)
+        # Gitlab::AppJsonLogger.info(
+        #   message: "pipeline_service create_merged_result_pipeline_for",
+        # )
         return cannot_create_pipeline_error unless can_create_merged_result_pipeline_for?(merge_request)
 
         result = ::MergeRequests::MergeabilityCheckService.new(merge_request).execute(recheck: true)
@@ -38,6 +41,9 @@ def create_merged_result_pipeline_for(merge_request)
               push_options: params[:push_options])
             .execute(:merge_request_event, merge_request: merge_request)
         else
+          # Gitlab::AppJsonLogger.info(
+          #   message: "pipeline_service create_merged_result_pipeline_for else",
+          # )
           cannot_create_pipeline_error
         end
       end
diff --git a/spec/workers/merge_requests/create_pipeline_worker_spec.rb b/spec/workers/merge_requests/create_pipeline_worker_spec.rb
index 5752fe987599a8..0f77ca9467ea9b 100644
--- a/spec/workers/merge_requests/create_pipeline_worker_spec.rb
+++ b/spec/workers/merge_requests/create_pipeline_worker_spec.rb
@@ -104,4 +104,39 @@
       it_behaves_like 'when object does not exist'
     end
   end
+
+  describe 'retry behavior' do
+    let(:user) { create(:user) }
+    let(:project) { create(:project) }
+    let(:merge_request) { create(:merge_request) }
+    let(:worker) { described_class.new }
+    let(:pipeline_creation_request) { Ci::PipelineCreation::Requests.start_for_merge_request(merge_request) }
+    let(:params) do
+      {
+        'pipeline_creation_request' => pipeline_creation_request,
+        'gitaly_context' => {}
+      }
+    end
+
+    subject { worker.perform(project.id, user.id, merge_request.id, params) }
+
+    context 'when service raises a retriable error' do
+      before do
+        allow_next_instance_of(MergeRequests::CreatePipelineService) do |service|
+          allow(service).to receive(:execute).and_raise(StandardError, 'Temporary failure')
+        end
+      end
+
+      it 'raises the error to trigger Sidekiq retry' do
+        expect { subject }.to raise_error(StandardError, 'Temporary failure')
+      end
+
+      it 'keeps status as IN_PROGRESS during retries', :clean_gitlab_redis_shared_state do
+        expect { subject }.to raise_error(StandardError)
+
+        result = Ci::PipelineCreation::Requests.hget(pipeline_creation_request)
+        expect(result['status']).to eq('in_progress')
+      end
+    end
+  end
 end
-- 
GitLab


From b7daac217b793fd77b5b655a2ae9d791436b83d2 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Tue, 25 Nov 2025 13:34:01 +0000
Subject: [PATCH 02/17] Remove duplicate failed status update

---
 app/services/merge_requests/create_pipeline_service.rb |  4 ----
 app/workers/merge_requests/create_pipeline_worker.rb   | 10 ++--------
 .../ee/merge_requests/create_pipeline_service.rb       |  6 ------
 3 files changed, 2 insertions(+), 18 deletions(-)

diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index 21951f22692398..1f94fdfbbdc6a1 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -98,10 +98,6 @@ def can_update_source_branch_in_target_project?(merge_request)
     end
 
     def cannot_create_pipeline_error
-      error_message = 'Cannot create a pipeline for this merge request.'
-
-      ::Ci::PipelineCreation::Requests.failed(params[:pipeline_creation_request], error_message)
-
       ServiceResponse.error(message: error_message, payload: nil, reason: :retriable_error)
     end
   end
diff --git a/app/workers/merge_requests/create_pipeline_worker.rb b/app/workers/merge_requests/create_pipeline_worker.rb
index ed6083da452d65..f7c970be40eba8 100644
--- a/app/workers/merge_requests/create_pipeline_worker.rb
+++ b/app/workers/merge_requests/create_pipeline_worker.rb
@@ -22,9 +22,7 @@ class CreatePipelineWorker
       merge_request = ::Ci::PipelineCreation::Requests.merge_request_from_key(pipeline_creation_request&.dig('key'))
 
       error_message = 'Cannot create a pipeline for this merge request after multiple retries.'
-      Gitlab::AppJsonLogger.info(
-        message: "pipeline_service sidekiq_retries_exhausted"
-      )
+
       ::Ci::PipelineCreation::Requests.failed(pipeline_creation_request, error_message)
       GraphqlTriggers.ci_pipeline_creation_requests_updated(merge_request)
     end
@@ -60,11 +58,7 @@ def perform(project_id, user_id, merge_request_id, params = {})
 
       # If the service returned a retriable error, raise to trigger Sidekiq retry
       # The request will only be marked as FAILED when retries are exhausted (see sidekiq_retries_exhausted hook)
-      Gitlab::AppJsonLogger.info(
-        message: "pipeline_service error",
-        error: result.error?,
-        reason: result.reason
-      )
+
       raise StandardError, result.message if result.error? && result.reason == :retriable_error
 
       merge_request.update_head_pipeline
diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index 6c5a72e7fee358..8d3b3ce1f53af3 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -21,9 +21,6 @@ def allowed?(merge_request)
       private
 
       def create_merged_result_pipeline_for(merge_request)
-        # Gitlab::AppJsonLogger.info(
-        #   message: "pipeline_service create_merged_result_pipeline_for",
-        # )
         return cannot_create_pipeline_error unless can_create_merged_result_pipeline_for?(merge_request)
 
         result = ::MergeRequests::MergeabilityCheckService.new(merge_request).execute(recheck: true)
@@ -41,9 +38,6 @@ def create_merged_result_pipeline_for(merge_request)
               push_options: params[:push_options])
             .execute(:merge_request_event, merge_request: merge_request)
         else
-          # Gitlab::AppJsonLogger.info(
-          #   message: "pipeline_service create_merged_result_pipeline_for else",
-          # )
           cannot_create_pipeline_error
         end
       end
-- 
GitLab


From a8c82bdda0cec5e536c8e0dea5872e302d5e0766 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Thu, 4 Dec 2025 09:37:26 +0000
Subject: [PATCH 03/17] Differentiate between temporary & permanent errors

---
 .../merge_requests/create_pipeline_service.rb | 24 ++++++++++++++++---
 .../merge_requests/create_pipeline_service.rb | 14 ++++++++---
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index 1f94fdfbbdc6a1..697492f2391a52 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -3,7 +3,13 @@
 module MergeRequests
   class CreatePipelineService < MergeRequests::BaseService
     def execute(merge_request)
-      return cannot_create_pipeline_error unless can_create_pipeline_for?(merge_request)
+      # Check for permanent validation errors first
+      return permanent_validation_error('no commits to build') if merge_request.has_no_commits?
+
+      # Check for retriable race conditions
+      if !allow_duplicate && merge_request.find_diff_head_pipeline&.merge_request?
+        return retriable_validation_error('duplicate pipeline detected')
+      end
 
       create_merge_request_pipeline(merge_request)
     end
@@ -97,8 +103,20 @@ def can_update_source_branch_in_target_project?(merge_request)
         .can_update_branch?(merge_request.source_branch)
     end
 
-    def cannot_create_pipeline_error
-      ServiceResponse.error(message: error_message, payload: nil, reason: :retriable_error)
+    def permanent_validation_error(reason)
+      message = "Cannot create a pipeline for this merge request: #{reason}."
+
+      # Mark as failed ASAP - no need to retry
+      ::Ci::PipelineCreation::Requests.failed(params[:pipeline_creation_request], message)
+
+      ServiceResponse.error(message: message, payload: nil)
+    end
+
+    def retriable_validation_error(reason)
+      message = "Cannot create a pipeline for this merge request: #{reason}."
+
+      # now THIS we retry
+      ServiceResponse.error(message: message, payload: nil, reason: :retriable_error)
     end
   end
 end
diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index 8d3b3ce1f53af3..53f806fbd4eef2 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -21,7 +21,13 @@ def allowed?(merge_request)
       private
 
       def create_merged_result_pipeline_for(merge_request)
-        return cannot_create_pipeline_error unless can_create_merged_result_pipeline_for?(merge_request)
+        unless can_create_merged_result_pipeline_for?(merge_request)
+          return permanent_validation_error('merged result pipeline not allowed')
+        end
+
+        if !allow_duplicate && merge_request.find_diff_head_pipeline&.merge_request?
+          return retriable_validation_error('duplicate pipeline detected')
+        end
 
         result = ::MergeRequests::MergeabilityCheckService.new(merge_request).execute(recheck: true)
 
@@ -38,7 +44,7 @@ def create_merged_result_pipeline_for(merge_request)
               push_options: params[:push_options])
             .execute(:merge_request_event, merge_request: merge_request)
         else
-          cannot_create_pipeline_error
+          permanent_validation_error('mergeability check failed')
         end
       end
 
@@ -46,7 +52,9 @@ def can_create_merged_result_pipeline_for?(merge_request)
         return false unless merge_request.project.merge_pipelines_enabled?
         return false unless can_create_pipeline_in_target_project?(merge_request)
 
-        can_create_pipeline_for?(merge_request)
+        return false if merge_request.has_no_commits?
+
+        true
       end
 
       def merge_status_race?(merge_request, result)
-- 
GitLab


From 793b1ded9c6625713ffa96ad501f7e3a9772f9b0 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Thu, 4 Dec 2025 09:37:50 +0000
Subject: [PATCH 04/17] Decrease retry exponential backoff duration

---
 app/workers/merge_requests/create_pipeline_worker.rb | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/app/workers/merge_requests/create_pipeline_worker.rb b/app/workers/merge_requests/create_pipeline_worker.rb
index f7c970be40eba8..051355a96f1592 100644
--- a/app/workers/merge_requests/create_pipeline_worker.rb
+++ b/app/workers/merge_requests/create_pipeline_worker.rb
@@ -6,7 +6,10 @@ class CreatePipelineWorker
 
     data_consistency :sticky
 
-    sidekiq_options retry: 3
+    sidekiq_options retry: 2
+    sidekiq_retry_in do |_count|
+      10
+    end
     include PipelineQueue
 
     queue_namespace :pipeline_creation
-- 
GitLab


From cc3a67742fe3ca172d0b2a70f0b072be4e854bd4 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Thu, 4 Dec 2025 15:47:55 +0000
Subject: [PATCH 05/17] Check pipeline status before retrying duplicate errors

---
 app/services/merge_requests/create_pipeline_service.rb    | 8 ++++++--
 .../services/ee/merge_requests/create_pipeline_service.rb | 8 ++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index 697492f2391a52..d5e0ad1bd0eb7b 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -7,8 +7,12 @@ def execute(merge_request)
       return permanent_validation_error('no commits to build') if merge_request.has_no_commits?
 
       # Check for retriable race conditions
-      if !allow_duplicate && merge_request.find_diff_head_pipeline&.merge_request?
-        return retriable_validation_error('duplicate pipeline detected')
+      unless allow_duplicate
+        existing_pipeline = merge_request.find_diff_head_pipeline
+
+        if existing_pipeline&.merge_request? && existing_pipeline.running_or_pending?
+          return retriable_validation_error('duplicate pipeline still in progress')
+        end
       end
 
       create_merge_request_pipeline(merge_request)
diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index 53f806fbd4eef2..ae22aea6b34acc 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -25,8 +25,12 @@ def create_merged_result_pipeline_for(merge_request)
           return permanent_validation_error('merged result pipeline not allowed')
         end
 
-        if !allow_duplicate && merge_request.find_diff_head_pipeline&.merge_request?
-          return retriable_validation_error('duplicate pipeline detected')
+        unless allow_duplicate
+          existing_pipeline = merge_request.find_diff_head_pipeline
+
+          if existing_pipeline&.merge_request? && existing_pipeline.running_or_pending?
+            return retriable_validation_error('duplicate pipeline still in progress')
+          end
         end
 
         result = ::MergeRequests::MergeabilityCheckService.new(merge_request).execute(recheck: true)
-- 
GitLab


From d3784640421439d07af9e858eb3970e838726f36 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Fri, 5 Dec 2025 10:23:01 +0000
Subject: [PATCH 06/17] Make merge pipelines enabled check retriable

---
 ee/app/services/ee/merge_requests/create_pipeline_service.rb | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index ae22aea6b34acc..bdc72bb8ef5659 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -21,6 +21,10 @@ def allowed?(merge_request)
       private
 
       def create_merged_result_pipeline_for(merge_request)
+        unless merge_request.project.merge_pipelines_enabled?
+          return retriable_validation_error('merge pipeline not enabled')
+        end
+
         unless can_create_merged_result_pipeline_for?(merge_request)
           return permanent_validation_error('merged result pipeline not allowed')
         end
@@ -53,7 +57,6 @@ def create_merged_result_pipeline_for(merge_request)
       end
 
       def can_create_merged_result_pipeline_for?(merge_request)
-        return false unless merge_request.project.merge_pipelines_enabled?
         return false unless can_create_pipeline_in_target_project?(merge_request)
 
         return false if merge_request.has_no_commits?
-- 
GitLab


From 240933b3426b13aa5112cc8286d666271204e3a8 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Fri, 5 Dec 2025 11:11:18 +0000
Subject: [PATCH 07/17] Increase retry count

---
 app/workers/merge_requests/create_pipeline_worker.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/workers/merge_requests/create_pipeline_worker.rb b/app/workers/merge_requests/create_pipeline_worker.rb
index 051355a96f1592..8042174b2fd0a0 100644
--- a/app/workers/merge_requests/create_pipeline_worker.rb
+++ b/app/workers/merge_requests/create_pipeline_worker.rb
@@ -6,7 +6,7 @@ class CreatePipelineWorker
 
     data_consistency :sticky
 
-    sidekiq_options retry: 2
+    sidekiq_options retry: 3
     sidekiq_retry_in do |_count|
       10
     end
-- 
GitLab


From aa3c73df595ef9c4b36eb70cc6f9d85f632e18b5 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Tue, 9 Dec 2025 11:42:50 +0000
Subject: [PATCH 08/17] Add tests and cleanup code

---
 .../merge_requests/create_pipeline_service.rb | 27 ++----
 .../merge_requests/create_pipeline_worker.rb  |  5 +-
 .../merge_requests/create_pipeline_service.rb | 10 +-
 .../create_pipeline_service_spec.rb           | 94 ++++++++++++++++++-
 4 files changed, 108 insertions(+), 28 deletions(-)

diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index d5e0ad1bd0eb7b..c7709968f9a595 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -3,15 +3,13 @@
 module MergeRequests
   class CreatePipelineService < MergeRequests::BaseService
     def execute(merge_request)
-      # Check for permanent validation errors first
-      return permanent_validation_error('no commits to build') if merge_request.has_no_commits?
+      return cannot_create_pipeline_error('no commits to build') if merge_request.has_no_commits?
 
-      # Check for retriable race conditions
       unless allow_duplicate
         existing_pipeline = merge_request.find_diff_head_pipeline
 
-        if existing_pipeline&.merge_request? && existing_pipeline.running_or_pending?
-          return retriable_validation_error('duplicate pipeline still in progress')
+        if existing_pipeline&.merge_request? && existing_pipeline.active?
+          return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
         end
       end
 
@@ -107,20 +105,15 @@ def can_update_source_branch_in_target_project?(merge_request)
         .can_update_branch?(merge_request.source_branch)
     end
 
-    def permanent_validation_error(reason)
+    def cannot_create_pipeline_error(reason, retriable: false)
       message = "Cannot create a pipeline for this merge request: #{reason}."
 
-      # Mark as failed ASAP - no need to retry
-      ::Ci::PipelineCreation::Requests.failed(params[:pipeline_creation_request], message)
-
-      ServiceResponse.error(message: message, payload: nil)
-    end
-
-    def retriable_validation_error(reason)
-      message = "Cannot create a pipeline for this merge request: #{reason}."
-
-      # now THIS we retry
-      ServiceResponse.error(message: message, payload: nil, reason: :retriable_error)
+      if retriable
+        ServiceResponse.error(message: message, payload: nil, reason: :retriable_error)
+      else
+        ::Ci::PipelineCreation::Requests.failed(params[:pipeline_creation_request], message)
+        ServiceResponse.error(message: message, payload: nil)
+      end
     end
   end
 end
diff --git a/app/workers/merge_requests/create_pipeline_worker.rb b/app/workers/merge_requests/create_pipeline_worker.rb
index 8042174b2fd0a0..0f05128df1f73f 100644
--- a/app/workers/merge_requests/create_pipeline_worker.rb
+++ b/app/workers/merge_requests/create_pipeline_worker.rb
@@ -59,10 +59,7 @@ def perform(project_id, user_id, merge_request_id, params = {})
           }
         ).execute(merge_request)
 
-      # If the service returned a retriable error, raise to trigger Sidekiq retry
-      # The request will only be marked as FAILED when retries are exhausted (see sidekiq_retries_exhausted hook)
-
-      raise StandardError, result.message if result.error? && result.reason == :retriable_error
+      raise StandardError, result.message if result&.error? && result.reason == :retriable_error
 
       merge_request.update_head_pipeline
 
diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index bdc72bb8ef5659..a3ab046d758361 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -22,18 +22,18 @@ def allowed?(merge_request)
 
       def create_merged_result_pipeline_for(merge_request)
         unless merge_request.project.merge_pipelines_enabled?
-          return retriable_validation_error('merge pipeline not enabled')
+          return cannot_create_pipeline_error('merge pipeline not enabled', retriable: true)
         end
 
         unless can_create_merged_result_pipeline_for?(merge_request)
-          return permanent_validation_error('merged result pipeline not allowed')
+          return cannot_create_pipeline_error('merged result pipeline not allowed')
         end
 
         unless allow_duplicate
           existing_pipeline = merge_request.find_diff_head_pipeline
 
-          if existing_pipeline&.merge_request? && existing_pipeline.running_or_pending?
-            return retriable_validation_error('duplicate pipeline still in progress')
+          if existing_pipeline&.merge_request? && existing_pipeline.active?
+            return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
           end
         end
 
@@ -52,7 +52,7 @@ def create_merged_result_pipeline_for(merge_request)
               push_options: params[:push_options])
             .execute(:merge_request_event, merge_request: merge_request)
         else
-          permanent_validation_error('mergeability check failed')
+          cannot_create_pipeline_error('mergeability check failed')
         end
       end
 
diff --git a/spec/services/merge_requests/create_pipeline_service_spec.rb b/spec/services/merge_requests/create_pipeline_service_spec.rb
index 19d71d8a90d11e..804bc9e5c54df3 100644
--- a/spec/services/merge_requests/create_pipeline_service_spec.rb
+++ b/spec/services/merge_requests/create_pipeline_service_spec.rb
@@ -173,7 +173,11 @@
     context 'when service is called multiple times' do
       it 'creates a pipeline once' do
         expect do
+          first_pipeline = service.execute(merge_request)
+          first_pipeline.payload.update!(status: :running)
           service.execute(merge_request)
+
+          allow(merge_request).to receive(:find_diff_head_pipeline).and_call_original
           service.execute(merge_request)
         end.to change { Ci::Pipeline.count }.by(1)
       end
@@ -266,12 +270,37 @@
         expect { response }.not_to change { Ci::Pipeline.count }
 
         expect(response).to be_error
-        expect(response.message).to eq('Cannot create a pipeline for this merge request.')
+        expect(response.message).to eq('Cannot create a pipeline for this merge request: no commits to build.')
         expect(response.payload).to be_nil
 
         failed_creation = ::Ci::PipelineCreation::Requests.hget(request)
         expect(failed_creation['status']).to eq(::Ci::PipelineCreation::Requests::FAILED)
-        expect(failed_creation['error']).to eq('Cannot create a pipeline for this merge request.')
+        expect(failed_creation['error']).to eq('Cannot create a pipeline for this merge request: no commits to build.')
+      end
+    end
+
+    context 'when duplicate pipeline is still in progress' do
+      let(:request) { ::Ci::PipelineCreation::Requests.start_for_merge_request(merge_request) }
+      let(:params) { { pipeline_creation_request: request } }
+
+      before do
+        existing_pipeline = create(:ci_pipeline, merge_requests_as_head_pipeline: [merge_request])
+        allow(existing_pipeline).to receive_messages(merge_request?: true, running_or_pending?: true)
+        allow(merge_request).to receive_messages(has_no_commits?: false, find_diff_head_pipeline: existing_pipeline)
+      end
+
+      it 'calls cannot_create_pipeline_error with retriable flag' do
+        response = service.execute(merge_request)
+
+        expect(response).to be_error
+        expect(response.message).to include('duplicate pipeline still in progress')
+      end
+
+      it 'keeps pipeline creation in progress for retry' do
+        service.execute(merge_request)
+
+        request_data = ::Ci::PipelineCreation::Requests.hget(params[:pipeline_creation_request])
+        expect(request_data['status']).to eq(::Ci::PipelineCreation::Requests::IN_PROGRESS)
       end
     end
 
@@ -394,4 +423,65 @@
       it { is_expected.to be_falsey }
     end
   end
+
+  describe '#cannot_create_pipeline_error' do
+    let(:service) { described_class.new(project: project, current_user: user, params: params) }
+    let(:params) { { pipeline_creation_request: { 'key' => '123', 'id' => '456' } } }
+    let(:merge_request) { create(:merge_request, source_project: project, target_project: project) }
+
+    context 'when called with retriable_error: false (default)' do
+      it 'returns an error response' do
+        response = service.send(:cannot_create_pipeline_error, 'test reason')
+
+        expect(response).to be_error
+        expect(response.message).to eq('Cannot create a pipeline for this merge request: test reason.')
+      end
+
+      it 'marks the pipeline creation request as failed' do
+        service.send(:cannot_create_pipeline_error, 'test reason')
+
+        failed_request = ::Ci::PipelineCreation::Requests.hget(params[:pipeline_creation_request])
+        expect(failed_request['status']).to eq(::Ci::PipelineCreation::Requests::FAILED)
+        expect(failed_request['error']).to eq('Cannot create a pipeline for this merge request: test reason.')
+      end
+
+      it 'includes the reason in the error message' do
+        response = service.send(:cannot_create_pipeline_error, 'custom failure reason')
+
+        expect(response.message).to include('custom failure reason')
+      end
+    end
+  end
+
+  describe '#cannot_create_pipeline_error with retriable_error flag' do
+    let(:merge_request) { create(:merge_request, source_project: project, target_project: project) }
+    let(:request) { ::Ci::PipelineCreation::Requests.start_for_merge_request(merge_request) }
+    let(:service) { described_class.new(project: project, current_user: user, params: params) }
+    let(:params) { { pipeline_creation_request: request } }
+
+    context 'when called with retriable: true' do
+      it 'returns an error response' do
+        response = service.send(:cannot_create_pipeline_error, 'test reason', retriable: true)
+
+        expect(response).to be_error
+        expect(response.message).to eq('Cannot create a pipeline for this merge request: test reason.')
+      end
+
+      it 'does NOT mark the pipeline creation request as failed' do
+        service.send(:cannot_create_pipeline_error, 'test reason', retriable: true)
+
+        # The request should still be in progress, not marked as failed
+        request_data = ::Ci::PipelineCreation::Requests.hget(params[:pipeline_creation_request])
+        expect(request_data['status']).to eq(::Ci::PipelineCreation::Requests::IN_PROGRESS)
+        expect(request_data['error']).to be_nil
+      end
+
+      it 'allows the worker to retry the job' do
+        response = service.send(:cannot_create_pipeline_error, 'duplicate pipeline still in progress', retriable: true)
+
+        expect(response).to be_error
+        expect(response.reason).to eq(:retriable_error)
+      end
+    end
+  end
 end
-- 
GitLab


From 7ef339ceee1b069a698f01f1dc605c4a71fe97bc Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Tue, 9 Dec 2025 11:57:16 +0000
Subject: [PATCH 09/17] Fixes duplicate pipeline tests

---
 .../ee/merge_requests/create_pipeline_service_spec.rb       | 6 +++++-
 .../services/merge_requests/create_pipeline_service_spec.rb | 6 ++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
index fdf4894d440ebd..be1d9b08f9ed4d 100644
--- a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
+++ b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
@@ -153,7 +153,11 @@
     context 'when the CreateService is retried' do
       it 'does not create a merge request pipeline twice' do
         expect do
-          2.times { service.execute(merge_request) }
+          first_pipeline = service.execute(merge_request)
+          first_pipeline.payload.update!(status: :running)
+
+          allow(merge_request).to receive(:find_diff_head_pipeline).and_call_original
+          service.execute(merge_request)
         end.to change { Ci::Pipeline.count }.by(1)
       end
     end
diff --git a/spec/services/merge_requests/create_pipeline_service_spec.rb b/spec/services/merge_requests/create_pipeline_service_spec.rb
index 804bc9e5c54df3..809ec7acfc28df 100644
--- a/spec/services/merge_requests/create_pipeline_service_spec.rb
+++ b/spec/services/merge_requests/create_pipeline_service_spec.rb
@@ -175,7 +175,6 @@
         expect do
           first_pipeline = service.execute(merge_request)
           first_pipeline.payload.update!(status: :running)
-          service.execute(merge_request)
 
           allow(merge_request).to receive(:find_diff_head_pipeline).and_call_original
           service.execute(merge_request)
@@ -187,7 +186,10 @@
 
         it 'creates pipelines multiple times' do
           expect do
-            service.execute(merge_request)
+            first_pipeline = service.execute(merge_request)
+            first_pipeline.payload.update!(status: :running)
+
+            allow(merge_request).to receive(:find_diff_head_pipeline).and_call_original
             service.execute(merge_request)
           end.to change { Ci::Pipeline.count }.by(2)
         end
-- 
GitLab


From b7ad3a21f297bcfcb9b9d550da0130ab8afd6441 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Wed, 10 Dec 2025 02:21:19 +0000
Subject: [PATCH 10/17] Fix #allowed tests

---
 .../services/ee/merge_requests/create_pipeline_service.rb   | 6 +++++-
 .../ee/merge_requests/create_pipeline_service_spec.rb       | 4 ++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index a3ab046d758361..61654c074cbace 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -15,7 +15,11 @@ def execute(merge_request)
       end
 
       def allowed?(merge_request)
-        (can_create_merged_result_pipeline_for?(merge_request) && user_can_run_pipeline?(merge_request)) || super
+        (
+          merge_request.project.merge_pipelines_enabled? &&
+        can_create_merged_result_pipeline_for?(merge_request) &&
+        user_can_run_pipeline?(merge_request)
+        ) || super
       end
 
       private
diff --git a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
index be1d9b08f9ed4d..d38c1b2031688a 100644
--- a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
+++ b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
@@ -218,6 +218,7 @@
 
     subject(:allowed) { service.allowed?(merge_request) }
 
+    let(:merge_pipelines_enabled) { true }
     let(:user_without_permissions) { create(:user) }
 
     where(:merged_result_pipeline_supported, :detached_mr_pipeline_supported, :user_can_run_pipeline, :result) do
@@ -244,6 +245,9 @@
           .and_return(detached_mr_pipeline_supported)
 
         project.add_developer(user) if user_can_run_pipeline
+
+        source_project.merge_pipelines_enabled = merge_pipelines_enabled
+        stub_licensed_features(merge_pipelines: true)
       end
 
       it 'matches the expected result' do
-- 
GitLab


From a608f9a069045579fe503fb081b6aae29888d947 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Wed, 10 Dec 2025 14:52:43 +0000
Subject: [PATCH 11/17] Fix failing invalid gitlab yml file test

---
 app/services/merge_requests/create_pipeline_service.rb        | 2 +-
 ee/app/services/ee/merge_requests/create_pipeline_service.rb  | 2 +-
 .../ee/merge_requests/create_pipeline_service_spec.rb         | 4 +++-
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index c7709968f9a595..c5560005a1cf66 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -8,7 +8,7 @@ def execute(merge_request)
       unless allow_duplicate
         existing_pipeline = merge_request.find_diff_head_pipeline
 
-        if existing_pipeline&.merge_request? && existing_pipeline.active?
+        if existing_pipeline&.merge_request?
           return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
         end
       end
diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index 61654c074cbace..6bcc58ee43303d 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -36,7 +36,7 @@ def create_merged_result_pipeline_for(merge_request)
         unless allow_duplicate
           existing_pipeline = merge_request.find_diff_head_pipeline
 
-          if existing_pipeline&.merge_request? && existing_pipeline.active?
+          if existing_pipeline&.merge_request?
             return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
           end
         end
diff --git a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
index d38c1b2031688a..0225890a983acd 100644
--- a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
+++ b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
@@ -208,7 +208,9 @@
 
       it 'responds with error', :aggregate_failures do
         expect(subject).to be_error
-        expect(subject.message).to eq('Cannot create a pipeline for this merge request.')
+        expect(subject.message).to eq(
+          'Cannot create a pipeline for this merge request: duplicate pipeline still in progress.'
+        )
       end
     end
   end
-- 
GitLab


From 744994680d4c74205a10275b39c58f78408be6d1 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Wed, 10 Dec 2025 15:34:11 +0000
Subject: [PATCH 12/17] Fix invalid gitlab-ci.yml spec by checking for failed
 pipelines

---
 app/services/merge_requests/create_pipeline_service.rb      | 6 +++++-
 .../ee/merge_requests/create_pipeline_service_spec.rb       | 2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index c5560005a1cf66..9041ac29cd73be 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -9,7 +9,11 @@ def execute(merge_request)
         existing_pipeline = merge_request.find_diff_head_pipeline
 
         if existing_pipeline&.merge_request?
-          return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
+          if existing_pipeline.running? || existing_pipeline.pending?
+            return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
+          end
+
+          return cannot_create_pipeline_error('duplicate pipeline') if existing_pipeline.failed?
         end
       end
 
diff --git a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
index 0225890a983acd..9387e7c92fe52c 100644
--- a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
+++ b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
@@ -209,7 +209,7 @@
       it 'responds with error', :aggregate_failures do
         expect(subject).to be_error
         expect(subject.message).to eq(
-          'Cannot create a pipeline for this merge request: duplicate pipeline still in progress.'
+          'Cannot create a pipeline for this merge request: duplicate pipeline.'
         )
       end
     end
-- 
GitLab


From 4746c8454d9bc90eee90bd71b317446a3685aa2c Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Thu, 11 Dec 2025 18:52:44 +0000
Subject: [PATCH 13/17] Add failed pipeline check

---
 .../ee/merge_requests/create_pipeline_service.rb       | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index 6bcc58ee43303d..793f1c673f8bdc 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -17,8 +17,8 @@ def execute(merge_request)
       def allowed?(merge_request)
         (
           merge_request.project.merge_pipelines_enabled? &&
-        can_create_merged_result_pipeline_for?(merge_request) &&
-        user_can_run_pipeline?(merge_request)
+          can_create_merged_result_pipeline_for?(merge_request) &&
+          user_can_run_pipeline?(merge_request)
         ) || super
       end
 
@@ -37,7 +37,11 @@ def create_merged_result_pipeline_for(merge_request)
           existing_pipeline = merge_request.find_diff_head_pipeline
 
           if existing_pipeline&.merge_request?
-            return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
+            if existing_pipeline.running? || existing_pipeline.pending?
+              return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
+            end
+
+            return cannot_create_pipeline_error('duplicate pipeline') if existing_pipeline.failed?
           end
         end
 
-- 
GitLab


From 024c3673dc997a34ac81c232094973ab1c1b7296 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Mon, 15 Dec 2025 13:13:06 +0000
Subject: [PATCH 14/17] Create a common helper function for duplicate check

---
 .../merge_requests/create_pipeline_service.rb | 29 ++++++++++++-------
 .../merge_requests/create_pipeline_worker.rb  |  7 +++--
 .../merge_requests/create_pipeline_service.rb | 13 ++-------
 3 files changed, 24 insertions(+), 25 deletions(-)

diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index 9041ac29cd73be..e3651d765582da 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -5,17 +5,8 @@ class CreatePipelineService < MergeRequests::BaseService
     def execute(merge_request)
       return cannot_create_pipeline_error('no commits to build') if merge_request.has_no_commits?
 
-      unless allow_duplicate
-        existing_pipeline = merge_request.find_diff_head_pipeline
-
-        if existing_pipeline&.merge_request?
-          if existing_pipeline.running? || existing_pipeline.pending?
-            return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
-          end
-
-          return cannot_create_pipeline_error('duplicate pipeline') if existing_pipeline.failed?
-        end
-      end
+      duplicate_error = check_duplicate_pipeline(merge_request)
+      return duplicate_error if duplicate_error
 
       create_merge_request_pipeline(merge_request)
     end
@@ -109,6 +100,22 @@ def can_update_source_branch_in_target_project?(merge_request)
         .can_update_branch?(merge_request.source_branch)
     end
 
+    def check_duplicate_pipeline(merge_request)
+      return if allow_duplicate
+
+      existing_pipeline = merge_request.find_diff_head_pipeline
+
+      if existing_pipeline&.merge_request?
+        if existing_pipeline.running? || existing_pipeline.pending?
+          return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
+        end
+
+        return cannot_create_pipeline_error('duplicate pipeline') if existing_pipeline.failed?
+      end
+
+      nil
+    end
+
     def cannot_create_pipeline_error(reason, retriable: false)
       message = "Cannot create a pipeline for this merge request: #{reason}."
 
diff --git a/app/workers/merge_requests/create_pipeline_worker.rb b/app/workers/merge_requests/create_pipeline_worker.rb
index 0f05128df1f73f..41abce49ed26e1 100644
--- a/app/workers/merge_requests/create_pipeline_worker.rb
+++ b/app/workers/merge_requests/create_pipeline_worker.rb
@@ -22,12 +22,13 @@ class CreatePipelineWorker
       pipeline_creation_request = job['args'][3]&.dig('pipeline_creation_request')
       next unless pipeline_creation_request
 
-      merge_request = ::Ci::PipelineCreation::Requests.merge_request_from_key(pipeline_creation_request&.dig('key'))
-
       error_message = 'Cannot create a pipeline for this merge request after multiple retries.'
 
       ::Ci::PipelineCreation::Requests.failed(pipeline_creation_request, error_message)
-      GraphqlTriggers.ci_pipeline_creation_requests_updated(merge_request)
+
+      merge_request = ::Ci::PipelineCreation::Requests.merge_request_from_key(pipeline_creation_request&.dig('key'))
+
+      GraphqlTriggers.ci_pipeline_creation_requests_updated(merge_request) if merge_request
     end
 
     def perform(project_id, user_id, merge_request_id, params = {})
diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index 793f1c673f8bdc..80409a69308217 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -33,17 +33,8 @@ def create_merged_result_pipeline_for(merge_request)
           return cannot_create_pipeline_error('merged result pipeline not allowed')
         end
 
-        unless allow_duplicate
-          existing_pipeline = merge_request.find_diff_head_pipeline
-
-          if existing_pipeline&.merge_request?
-            if existing_pipeline.running? || existing_pipeline.pending?
-              return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
-            end
-
-            return cannot_create_pipeline_error('duplicate pipeline') if existing_pipeline.failed?
-          end
-        end
+        duplicate_error = check_duplicate_pipeline(merge_request)
+        return duplicate_error if duplicate_error
 
         result = ::MergeRequests::MergeabilityCheckService.new(merge_request).execute(recheck: true)
 
-- 
GitLab


From 9a37a422107e5aedba19354f29ee0e33d4aba681 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Mon, 15 Dec 2025 17:17:07 +0000
Subject: [PATCH 15/17] Directly return service error when merge requests are
 not enabled

---
 ee/app/services/ee/merge_requests/create_pipeline_service.rb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/ee/app/services/ee/merge_requests/create_pipeline_service.rb b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
index 80409a69308217..e963db3bc3e0e2 100644
--- a/ee/app/services/ee/merge_requests/create_pipeline_service.rb
+++ b/ee/app/services/ee/merge_requests/create_pipeline_service.rb
@@ -26,7 +26,9 @@ def allowed?(merge_request)
 
       def create_merged_result_pipeline_for(merge_request)
         unless merge_request.project.merge_pipelines_enabled?
-          return cannot_create_pipeline_error('merge pipeline not enabled', retriable: true)
+          return ServiceResponse.error(
+            message: 'Cannot create a pipeline for this merge request: merge pipelines not enabled'
+          )
         end
 
         unless can_create_merged_result_pipeline_for?(merge_request)
-- 
GitLab


From 4f1d92f928f46f2d6606571e7e13adf241c1725d Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Tue, 16 Dec 2025 12:07:47 +0000
Subject: [PATCH 16/17] Ensure that the duplicate pipeline check only runs for
 the same commit

---
 app/services/merge_requests/create_pipeline_service.rb      | 4 ++--
 .../ee/merge_requests/create_pipeline_service_spec.rb       | 6 ++----
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index e3651d765582da..d067bc4e6ef4b0 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -105,12 +105,12 @@ def check_duplicate_pipeline(merge_request)
 
       existing_pipeline = merge_request.find_diff_head_pipeline
 
-      if existing_pipeline&.merge_request?
+      if existing_pipeline&.merge_request? && existing_pipeline&.sha == merge_request.diff_head_sha
         if existing_pipeline.running? || existing_pipeline.pending?
           return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
         end
 
-        return cannot_create_pipeline_error('duplicate pipeline') if existing_pipeline.failed?
+        return cannot_create_pipeline_error('duplicate pipeline')
       end
 
       nil
diff --git a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
index 9387e7c92fe52c..b5f97a9d97ea28 100644
--- a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
+++ b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
@@ -152,11 +152,9 @@
 
     context 'when the CreateService is retried' do
       it 'does not create a merge request pipeline twice' do
+        service.execute(merge_request)
+        merge_request.reload
         expect do
-          first_pipeline = service.execute(merge_request)
-          first_pipeline.payload.update!(status: :running)
-
-          allow(merge_request).to receive(:find_diff_head_pipeline).and_call_original
           service.execute(merge_request)
         end.to change { Ci::Pipeline.count }.by(1)
       end
-- 
GitLab


From 220ea44b1f2311c3b57309ae33e0fc6372c2d7f5 Mon Sep 17 00:00:00 2001
From: Sahil Sharma <sasharma@gitlab.com>
Date: Tue, 16 Dec 2025 15:51:49 +0000
Subject: [PATCH 17/17] Using pipeline `merge_request_diff_sha` instead of
 `sha` for comparing same commit

---
 app/models/ci/pipeline.rb                            | 12 ++++++------
 .../merge_requests/create_pipeline_service.rb        |  2 +-
 .../merge_requests/create_pipeline_service_spec.rb   |  4 +---
 .../merge_requests/create_pipeline_service_spec.rb   |  6 +++++-
 4 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/app/models/ci/pipeline.rb b/app/models/ci/pipeline.rb
index 1fb1cf4132c30a..7a90dfee8e1e93 100644
--- a/app/models/ci/pipeline.rb
+++ b/app/models/ci/pipeline.rb
@@ -1656,12 +1656,6 @@ def cancel_async_on_job_failure
       end
     end
 
-    private
-
-    def add_message(severity, content)
-      messages.build(severity: severity, content: content, project_id: project_id)
-    end
-
     def merge_request_diff_sha
       return unless merge_request?
 
@@ -1672,6 +1666,12 @@ def merge_request_diff_sha
       end
     end
 
+    private
+
+    def add_message(severity, content)
+      messages.build(severity: severity, content: content, project_id: project_id)
+    end
+
     def push_details
       strong_memoize(:push_details) do
         Gitlab::Git::Push.new(project, before_sha, sha, git_ref)
diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
index d067bc4e6ef4b0..d2fa8b9030f9a8 100644
--- a/app/services/merge_requests/create_pipeline_service.rb
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -105,7 +105,7 @@ def check_duplicate_pipeline(merge_request)
 
       existing_pipeline = merge_request.find_diff_head_pipeline
 
-      if existing_pipeline&.merge_request? && existing_pipeline&.sha == merge_request.diff_head_sha
+      if existing_pipeline&.merge_request? && existing_pipeline&.merge_request_diff_sha == merge_request.diff_head_sha
         if existing_pipeline.running? || existing_pipeline.pending?
           return cannot_create_pipeline_error('duplicate pipeline still in progress', retriable: true)
         end
diff --git a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
index b5f97a9d97ea28..bd5a82c6ed9f6b 100644
--- a/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
+++ b/ee/spec/services/ee/merge_requests/create_pipeline_service_spec.rb
@@ -152,10 +152,8 @@
 
     context 'when the CreateService is retried' do
       it 'does not create a merge request pipeline twice' do
-        service.execute(merge_request)
-        merge_request.reload
         expect do
-          service.execute(merge_request)
+          2.times { service.execute(merge_request) }
         end.to change { Ci::Pipeline.count }.by(1)
       end
     end
diff --git a/spec/services/merge_requests/create_pipeline_service_spec.rb b/spec/services/merge_requests/create_pipeline_service_spec.rb
index 809ec7acfc28df..485ba9987a75e1 100644
--- a/spec/services/merge_requests/create_pipeline_service_spec.rb
+++ b/spec/services/merge_requests/create_pipeline_service_spec.rb
@@ -287,7 +287,11 @@
 
       before do
         existing_pipeline = create(:ci_pipeline, merge_requests_as_head_pipeline: [merge_request])
-        allow(existing_pipeline).to receive_messages(merge_request?: true, running_or_pending?: true)
+        allow(existing_pipeline).to receive_messages(
+          merge_request?: true,
+          running_or_pending?: true,
+          merge_request_diff_sha: merge_request.diff_head_sha
+        )
         allow(merge_request).to receive_messages(has_no_commits?: false, find_diff_head_pipeline: existing_pipeline)
       end
 
-- 
GitLab