=s_('ProjectSettings|To enable this feature, configure pipelines. %{link_start}How to configure pipelines for merge requests?%{link_end}').html_safe%{link_start: configuring_pipelines_for_merge_requests_help_link_start,link_end: '</a>'.html_safe}
@@ -802,7 +802,7 @@ Managed Redis from cloud providers (such as AWS ElastiCache) will work. If these
services support high availability, be sure it _isn't_ of the Redis Cluster type.
Redis version 5.0 or higher is required, which is included with Omnibus GitLab
packages starting with GitLab 13.0. Older Redis versions don't support an
optional count argument to SPOP, which is required for [Merge Trains](../../ci/merge_request_pipelines/pipelines_for_merged_results/merge_trains/index.md).
optional count argument to SPOP, which is required for [Merge Trains](../../ci/pipelines/merge_trains.md).
Note the Redis node's IP address or hostname, port, and password (if required).
These will be necessary later when configuring the [GitLab application servers](#configure-gitlab-rails).
@@ -804,7 +804,7 @@ Managed Redis from cloud providers (such as AWS ElastiCache) will work. If these
services support high availability, be sure it _isn't_ of the Redis Cluster type.
Redis version 5.0 or higher is required, which is included with Omnibus GitLab
packages starting with GitLab 13.0. Older Redis versions don't support an
optional count argument to SPOP, which is required for [Merge Trains](../../ci/merge_request_pipelines/pipelines_for_merged_results/merge_trains/index.md).
optional count argument to SPOP, which is required for [Merge Trains](../../ci/pipelines/merge_trains.md).
Note the Redis node's IP address or hostname, port, and password (if required).
These will be necessary later when configuring the [GitLab application servers](#configure-gitlab-rails).
@@ -812,7 +812,7 @@ Managed Redis from cloud providers (such as AWS ElastiCache) will work. If these
services support high availability, be sure it _isn't_ of the Redis Cluster type.
Redis version 5.0 or higher is required, which is included with Omnibus GitLab
packages starting with GitLab 13.0. Older Redis versions don't support an
optional count argument to SPOP, which is required for [Merge Trains](../../ci/merge_request_pipelines/pipelines_for_merged_results/merge_trains/index.md).
optional count argument to SPOP, which is required for [Merge Trains](../../ci/pipelines/merge_trains.md).
Note the Redis node's IP address or hostname, port, and password (if required).
These will be necessary later when configuring the [GitLab application servers](#configure-gitlab-rails).
| [Git submodules for CI/CD](git_submodules.md) | Configure jobs for using Git submodules. |
| [SSH keys for CI/CD](ssh_keys/index.md) | Using SSH keys in your CI pipelines. |
| [Pipeline triggers](triggers/index.md) | Trigger pipelines through the API. |
| [Pipelines for Merge Requests](merge_request_pipelines/index.md) | Design a pipeline structure for running a pipeline in merge requests. |
| [Pipelines for Merge Requests](pipelines/merge_request_pipelines.md) | Design a pipeline structure for running a pipeline in merge requests. |
| [Integrate with Kubernetes clusters](../user/project/clusters/index.md) | Connect your project to Google Kubernetes Engine (GKE) or an existing Kubernetes cluster. |
| [Optimize GitLab and GitLab Runner for large repositories](large_repositories/index.md) | Recommended strategies for handling large repositories. |
| [`.gitlab-ci.yml` full reference](yaml/index.md) | All the attributes you can use with GitLab CI/CD. |
- If the pipeline is for a merge request, the first rule matches, and the job
is added to the [merge request pipeline](../merge_request_pipelines/index.md)
is added to the [merge request pipeline](../pipelines/merge_request_pipelines.md)
with attributes of:
-`when: manual` (manual job)
-`allow_failure: true` (the pipeline continues running even if the manual job is not run)
...
...
@@ -220,7 +220,7 @@ check the value of the `$CI_PIPELINE_SOURCE` variable:
| `chat` | For pipelines created by using a [GitLab ChatOps](../chatops/index.md) command. |
| `external` | When you use CI services other than GitLab. |
| `external_pull_request_event` | When an external pull request on GitHub is created or updated. See [Pipelines for external pull requests](../ci_cd_for_external_repos/index.md#pipelines-for-external-pull-requests). |
| `merge_request_event` | For pipelines created when a merge request is created or updated. Required to enable [merge request pipelines](../merge_request_pipelines/index.md), [merged results pipelines](../merge_request_pipelines/pipelines_for_merged_results/index.md), and [merge trains](../merge_request_pipelines/pipelines_for_merged_results/merge_trains/index.md). |
| `merge_request_event` | For pipelines created when a merge request is created or updated. Required to enable [merge request pipelines](../pipelines/merge_request_pipelines.md), [merged results pipelines](../pipelines/pipelines_for_merged_results.md), and [merge trains](../pipelines/merge_trains.md). |
| `parent_pipeline` | For pipelines triggered by a [parent/child pipeline](../parent_child_pipelines.md) with `rules`. Use this pipeline source in the child pipeline configuration so that it can be triggered by the parent pipeline. |
| `pipeline` | For [multi-project pipelines](../multi_project_pipelines.md) created by [using the API with `CI_JOB_TOKEN`](../multi_project_pipelines.md#create-multi-project-pipelines-by-using-the-api), or the [`trigger`](../yaml/index.md#trigger) keyword. |
| `push` | For pipelines triggered by a `git push` event, including for branches and tags. |
...
...
@@ -243,7 +243,7 @@ job:
-if:'$CI_PIPELINE_SOURCE=="push"'
```
The following example runs the job as a `when: on_success` job in [merge request pipelines](../merge_request_pipelines/index.md)
The following example runs the job as a `when: on_success` job in [merge request pipelines](../pipelines/merge_request_pipelines.md)
and scheduled pipelines. It does not run in any other pipeline type.
```yaml
...
...
@@ -382,7 +382,7 @@ Read more about how to use `only:changes` and `except:changes`:
#### Use `only:changes` with pipelines for merge requests
With [pipelines for merge requests](../merge_request_pipelines/index.md),
With [pipelines for merge requests](../pipelines/merge_request_pipelines.md),
it's possible to define a job to be created based on files modified
in a merge request.
...
...
@@ -432,7 +432,7 @@ properly corrects any failures from previous pipelines.
#### Use `only:changes` without pipelines for merge requests
Without [pipelines for merge requests](../merge_request_pipelines/index.md), pipelines
Without [pipelines for merge requests](../pipelines/merge_request_pipelines.md), pipelines
run on branches or tags that don't have an explicit association with a merge request.
In this case, a previous SHA is used to calculate the diff, which is equivalent to `git diff HEAD~`.
This can result in some unexpected behavior, including:
...
...
@@ -511,7 +511,7 @@ types the variables can control for:
- Branch pipelines that run for Git `push` events to a branch, like new commits or tags.
- Tag pipelines that run only when a new Git tag is pushed to a branch.
-[Merge request pipelines](../merge_request_pipelines/index.md) that run for changes
-[Merge request pipelines](../pipelines/merge_request_pipelines.md) that run for changes
to a merge request, like new commits or selecting the **Run pipeline** button
info:To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
- You must have the Developer [role](../../user/permissions.md)
to run a pipeline for merge requests.
## Configure pipelines for merge requests
To configure pipelines for merge requests, you must configure your [CI/CD configuration file](../yaml/index.md).
To do this, you can use [`rules`](#use-rules-to-run-pipelines-for-merge-requests) or [`only/except`](#use-only-or-except-to-run-pipelines-for-merge-requests).
### Use `rules` to run pipelines for merge requests
GitLab recommends that you use the `rules` keyword, which is available in
### Use `only` or `except` to run pipelines for merge requests
You can use the `only/except` keywords. However, with this method, you must specify `only: - merge_requests` for each job.
In the following example, the pipeline contains a `test` job that is configured to run on merge requests.
The `build` and `deploy` jobs don't have the `only: - merge_requests` keyword,
so they don't run on merge requests.
```yaml
build:
stage:build
script:./build
only:
-main
test:
stage:test
script:./test
only:
-merge_requests
deploy:
stage:deploy
script:./deploy
only:
-main
```
#### Exclude specific jobs
When you use `only: [merge_requests]`, only jobs with
that keyword are run in the context of a merge request. No other jobs run.
However, you can invert this behavior and have all of your jobs run except
for one or two. For example, you might have a pipeline with jobs `A`, `B`, and `C`, and you want:
- All pipelines to always run `A` and `B`.
-`C` to run only for merge requests.
To achieve this outcome, configure your `.gitlab-ci.yml` file as follows:
```yaml
.only-default:&only-default
only:
-main
-merge_requests
-tags
A:
<<:*only-default
script:
-...
B:
<<:*only-default
script:
-...
C:
script:
-...
only:
-merge_requests
```
-`A` and `B` always run, because they get the `only:` rule to execute in all cases.
-`C` only runs for merge requests. It doesn't run for any pipeline
except a merge request pipeline.
In this example, you don't have to add the `only:` rule to all of your jobs to make
them always run. You can use this format to set up a Review App, which helps to
save resources.
#### Exclude specific branches
Branch refs use this format: `refs/heads/my-feature-branch`.
Merge request refs use this format: `refs/merge-requests/:iid/head`.
Because of this difference, the following configuration does not work as expected:
```yaml
# Does not exclude a branch named "docs-my-fix"!
test:
only:[merge_requests]
except:[/^docs-/]
```
Instead, use the
[`$CI_COMMIT_REF_NAME` predefined environment
variable](../variables/predefined_variables.md) in
combination with
[`only:variables`](../yaml/index.md#onlyvariables--exceptvariables) to
accomplish this behavior:
```yaml
test:
only:[merge_requests]
except:
variables:
-$CI_COMMIT_REF_NAME =~ /^docs-/
```
## Run pipelines in the parent project for merge requests from a forked project **(PREMIUM)**
> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/217451) in GitLab 13.3.
> - [Moved](https://about.gitlab.com/blog/2021/01/26/new-gitlab-product-subscription-model/) to GitLab Premium in 13.9.
By default, external contributors who work in forks can't create pipelines in the
parent project. When a merge request that comes from a fork triggers a pipeline:
- The pipeline is created and runs in the fork (source) project, not the parent (target) project.
- The pipeline uses the fork project's CI/CD configuration and resources.
If a pipeline runs in a fork, a **fork** badge appears for the pipeline in the merge request.
Sometimes parent project members want the pipeline to run in the parent
project. They may want to ensure that the post-merge pipeline passes in the parent project.
For example, a fork project could try to use a corrupted runner that doesn't execute
test scripts properly, but reports a passed pipeline. Reviewers in the parent project
could mistakenly trust the merge request because it passed a faked pipeline.
Parent project members with at least the [Developer role](../../user/permissions.md)
can create pipelines in the parent project for merge requests
from a forked project. In the merge request, go to the **Pipelines** tab and select
**Run pipeline**.
WARNING:
Fork merge requests can contain malicious code that tries to steal secrets in the
parent project when the pipeline runs, even before merge. As a reviewer, you must carefully
check the changes in the merge request before triggering the pipeline. GitLab shows
a warning that you must accept before you can trigger the pipeline.
## Predefined variables available for pipelines for merge requests
When you use pipelines for merge requests, [additional predefined variables](../variables/predefined_variables.md#predefined-variables-for-merge-request-pipelines) are available to the CI/CD jobs.
These variables contain information from the associated merge request, so that you can
integrate your job with the [GitLab Merge Request API](../../api/merge_requests.md).
## Troubleshooting
### Two pipelines created when pushing to a merge request
If you are experiencing duplicated pipelines when using `rules`, take a look at
the [important differences between `rules` and `only`/`except`](../jobs/job_control.md#avoid-duplicate-pipelines),
which helps you get your starting configuration correct.
If you are seeing two pipelines when using `only/except`, please see the caveats
related to using `only/except` above (or, consider moving to `rules`).
In [GitLab 13.7](https://gitlab.com/gitlab-org/gitlab/-/issues/201845) and later,
you can add `workflow:rules` to [switch from branch pipelines to merge request pipelines](../yaml/index.md#switch-between-branch-pipelines-and-merge-request-pipelines).
After a merge request is open on the branch, the pipeline switches to a merge request pipeline.
### Two pipelines created when pushing an invalid CI configuration file
Pushing to a branch with an invalid CI configuration file can trigger
the creation of two types of failed pipelines. One pipeline is a failed merge request
pipeline, and the other is a failed branch pipeline, but both are caused by the same
invalid configuration.
## Related topics
-[Pipelines for merged results](pipelines_for_merged_results/index.md).
info:To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
This document was moved to [another location](../../pipelines/pipelines_for_merged_results.md).
> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/7380) in [GitLab Premium](https://about.gitlab.com/pricing/) 11.10.
When you submit a merge request, you are requesting to merge changes from a
source branch into a target branch. By default, the CI pipeline runs jobs
against the source branch.
With *pipelines for merged results*, the pipeline runs as if the changes from
the source branch have already been merged into the target branch. The commit shown for the pipeline does not exist on the source or target branches but represents the combined target and source branches.
If the pipeline fails due to a problem in the target branch, you can wait until the
target is fixed and re-run the pipeline.
This new pipeline runs as if the source is merged with the updated target, and you
don't need to rebase.
The pipeline does not automatically run when the target branch changes. Only changes
to the source branch trigger a new pipeline. If a long time has passed since the last successful
pipeline, you may want to re-run it before merge, to ensure that the source changes
can still be successfully merged into the target.
When the merge request can't be merged, the pipeline runs against the source branch only. For example, when:
- The target branch has changes that conflict with the changes in the source branch.
- The merge request is a [**Draft** merge request](../../../user/project/merge_requests/drafts.md).
In these cases, the pipeline runs as a [pipeline for merge requests](../index.md)
and is labeled as `detached`. If these cases no longer exist, new pipelines
again run against the merged results.
Any user who has developer [permissions](../../../user/permissions.md) can run a
pipeline for merged results.
## Prerequisites
To enable pipelines for merge results:
- You must have the [Maintainer role](../../../user/permissions.md).
- You must be using [GitLab Runner](https://gitlab.com/gitlab-org/gitlab-runner) 11.9 or later.
info:To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
type:reference
last_update:2019-07-03
redirect_to:'../../../pipelines/merge_trains.md'
---
# Merge Trains **(PREMIUM)**
This document was moved to [another location](../../../pipelines/merge_trains.md).
> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/9186) in [GitLab Premium](https://about.gitlab.com/pricing/) 12.0.
> - [Squash and merge](../../../../user/project/merge_requests/squash_and_merge.md) support [introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/13001) in [GitLab Premium](https://about.gitlab.com/pricing/) 12.6.
For more information about why you might want to use Merge Trains, read [How merge trains keep your master green](https://about.gitlab.com/blog/2020/01/30/all-aboard-merge-trains/).
When [pipelines for merged results](../index.md#pipelines-for-merged-results) are
enabled, the pipeline jobs run as if the changes from your source branch have already
been merged into the target branch.
However, the target branch may be changing rapidly. When you're ready to merge,
if you haven't run the pipeline in a while, the target branch may have already changed.
Merging now could introduce breaking changes.
*Merge trains* can prevent this from happening. A merge train is a queued list of merge
requests, each waiting to be merged into the target branch.
Many merge requests can be added to the train. Each merge request runs its own merged results pipeline,
which includes the changes from all of the other merge requests in *front* of it on the train.
All the pipelines run in parallel, to save time.
If the pipeline for a merge request fails, the breaking changes are not merged, and the target
branch is unaffected. The merge request is removed from the train, and all pipelines behind it restart.
If the pipeline for the merge request at the front of the train completes successfully,
the changes are merged into the target branch, and the other pipelines continue to
run.
To add a merge request to a merge train, you need [permissions](../../../../user/permissions.md) to push to the target branch.
Each merge train can run a maximum of **twenty** pipelines in parallel.
If more than twenty merge requests are added to the merge train, the merge requests
are queued until a slot in the merge train is free. There is no limit to the
number of merge requests that can be queued.
## Merge train example
Three merge requests (`A`, `B` and `C`) are added to a merge train in order, which
creates three merged results pipelines that run in parallel:
1. The first pipeline runs on the changes from `A` combined with the target branch.
1. The second pipeline runs on the changes from `A` and `B` combined with the target branch.
1. The third pipeline runs on the changes from `A`, `B`, and `C` combined with the target branch.
If the pipeline for `B` fails, it is removed from the train. The pipeline for
`C` restarts with the `A` and `C` changes, but without the `B` changes.
If `A` then completes successfully, it merges into the target branch, and `C` continues
to run. If more merge requests are added to the train, they now include the `A`
changes that are included in the target branch, and the `C` changes that are from
the merge request already in the train.
Read more about [how merge trains keep your master green](https://about.gitlab.com/blog/2020/01/30/all-aboard-merge-trains/).
[Merge When Pipeline Succeeds](../../../../user/project/merge_requests/merge_when_pipeline_succeeds.md)
is currently unavailable when Merge Trains are enabled.
See [the related issue](https://gitlab.com/gitlab-org/gitlab/-/issues/12267)
for more information.
### Merge Train Pipeline cannot be retried
When a pipeline for merge trains fails the merge request is dropped from the train and the pipeline can't be retried.
Pipelines for merge trains run on the merged result of the changes in the merge request and
the changes from other merge requests already on the train. If the merge request is dropped from the train,
the merged result is out of date and the pipeline can't be retried.
Instead, you should [add the merge request to the train](#add-a-merge-request-to-a-merge-train)
again, which triggers a new pipeline.
### Unable to add to merge train with message "The pipeline for this merge request failed."
Sometimes the **Start/Add to Merge Train** button is not available and the merge request says,
"The pipeline for this merge request failed. Please retry the job or push a new commit to fix the failure."
This issue occurs when [**Pipelines must succeed**](../../../../user/project/merge_requests/merge_when_pipeline_succeeds.md#only-allow-merge-requests-to-be-merged-if-the-pipeline-succeeds)
is enabled in **Settings > General > Merge requests**. This option requires that you
run a new successful pipeline before you can re-add a merge request to a merge train.
Merge trains ensure that each pipeline has succeeded before a merge happens, so
you can clear the **Pipelines must succeed** check box and keep
**Enable merge trains and pipelines for merged results** (merge trains) enabled.
If you want to keep the **Pipelines must succeed** option enabled along with Merge
Trains, create a new pipeline for merged results when this error occurs:
1. Go to the **Pipelines** tab and click **Run pipeline**.
1. Click **Start/Add to merge train when pipeline succeeds**.
See [the related issue](https://gitlab.com/gitlab-org/gitlab/-/issues/35135)
for more information.
### Merge Trains feature flag **(PREMIUM SELF)**
In [GitLab 13.6 and later](https://gitlab.com/gitlab-org/gitlab/-/issues/244831),
you can [enable or disable merge trains in the project settings](#enable-merge-trains).
In GitLab 13.5 and earlier, merge trains are automatically enabled when
[pipelines for merged results](../index.md#pipelines-for-merged-results) are enabled.
To use pipelines for merged results without using merge trains, you can enable a
[feature flag](../../../../user/feature_flags.md) that blocks the merge trains feature.
[GitLab administrators with access to the GitLab Rails console](../../../../administration/feature_flags.md)
can enable the feature flag to disable merge trains:
```ruby
Feature.enable(:disable_merge_trains)
```
After you enable this feature flag, all existing merge trains are cancelled and
the **Start/Add to Merge Train** button no longer appears in merge requests.
To disable the feature flag, and enable merge trains again:
```ruby
Feature.disable(:disable_merge_trains)
```
<!-- This redirect file can be deleted after 2021-09-29. -->
<!-- Before deletion, see: https://docs.gitlab.com/ee/development/documentation/#move-or-rename-a-page -->
info:To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
type:reference, index
last_update:2019-07-03
---
# Pipelines for merge requests **(FREE)**
> [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/15310) in GitLab 11.6.
In a [basic configuration](pipeline_architectures.md#basic-pipelines), GitLab runs a pipeline each time
changes are pushed to a branch.
If you want the pipeline to run jobs **only** on commits associated with a merge request,
you can use *pipelines for merge requests*.
In the UI, these pipelines are labeled as `detached`. Otherwise, these pipelines are the same
as other pipelines.
Pipelines for merge requests can run when you:
- Create a new merge request.
- Commit changes to the source branch for the merge request.
- Select the **Run pipeline** button from the **Pipelines** tab in the merge request.
If you use this feature with [merge when pipeline succeeds](../../user/project/merge_requests/merge_when_pipeline_succeeds.md),
pipelines for merge requests take precedence over other pipelines.
## Prerequisites
To enable pipelines for merge requests:
- Your repository must be a GitLab repository, not an
- You must have the Developer [role](../../user/permissions.md)
to run a pipeline for merge requests.
## Configure pipelines for merge requests
To configure pipelines for merge requests, you must configure your [CI/CD configuration file](../yaml/index.md).
To do this, you can use [`rules`](#use-rules-to-run-pipelines-for-merge-requests) or [`only/except`](#use-only-or-except-to-run-pipelines-for-merge-requests).
### Use `rules` to run pipelines for merge requests
GitLab recommends that you use the `rules` keyword, which is available in
### Use `only` or `except` to run pipelines for merge requests
You can use the `only/except` keywords. However, with this method, you must specify `only: - merge_requests` for each job.
In the following example, the pipeline contains a `test` job that is configured to run on merge requests.
The `build` and `deploy` jobs don't have the `only: - merge_requests` keyword,
so they don't run on merge requests.
```yaml
build:
stage:build
script:./build
only:
-main
test:
stage:test
script:./test
only:
-merge_requests
deploy:
stage:deploy
script:./deploy
only:
-main
```
#### Exclude specific jobs
When you use `only: [merge_requests]`, only jobs with
that keyword are run in the context of a merge request. No other jobs run.
However, you can invert this behavior and have all of your jobs run except
for one or two. For example, you might have a pipeline with jobs `A`, `B`, and `C`, and you want:
- All pipelines to always run `A` and `B`.
-`C` to run only for merge requests.
To achieve this outcome, configure your `.gitlab-ci.yml` file as follows:
```yaml
.only-default:&only-default
only:
-main
-merge_requests
-tags
A:
<<:*only-default
script:
-...
B:
<<:*only-default
script:
-...
C:
script:
-...
only:
-merge_requests
```
-`A` and `B` always run, because they get the `only:` rule to execute in all cases.
-`C` only runs for merge requests. It doesn't run for any pipeline
except a merge request pipeline.
In this example, you don't have to add the `only:` rule to all of your jobs to make
them always run. You can use this format to set up a Review App, which helps to
save resources.
#### Exclude specific branches
Branch refs use this format: `refs/heads/my-feature-branch`.
Merge request refs use this format: `refs/merge-requests/:iid/head`.
Because of this difference, the following configuration does not work as expected:
```yaml
# Does not exclude a branch named "docs-my-fix"!
test:
only:[merge_requests]
except:[/^docs-/]
```
Instead, use the
[`$CI_COMMIT_REF_NAME` predefined environment
variable](../variables/predefined_variables.md) in
combination with
[`only:variables`](../yaml/index.md#onlyvariables--exceptvariables) to
accomplish this behavior:
```yaml
test:
only:[merge_requests]
except:
variables:
-$CI_COMMIT_REF_NAME =~ /^docs-/
```
## Run pipelines in the parent project for merge requests from a forked project **(PREMIUM)**
> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/217451) in GitLab 13.3.
> - [Moved](https://about.gitlab.com/blog/2021/01/26/new-gitlab-product-subscription-model/) to GitLab Premium in 13.9.
By default, external contributors who work in forks can't create pipelines in the
parent project. When a merge request that comes from a fork triggers a pipeline:
- The pipeline is created and runs in the fork (source) project, not the parent (target) project.
- The pipeline uses the fork project's CI/CD configuration and resources.
If a pipeline runs in a fork, a **fork** badge appears for the pipeline in the merge request.
Sometimes parent project members want the pipeline to run in the parent
project. They may want to ensure that the post-merge pipeline passes in the parent project.
For example, a fork project could try to use a corrupted runner that doesn't execute
test scripts properly, but reports a passed pipeline. Reviewers in the parent project
could mistakenly trust the merge request because it passed a faked pipeline.
Parent project members with at least the [Developer role](../../user/permissions.md)
can create pipelines in the parent project for merge requests
from a forked project. In the merge request, go to the **Pipelines** tab and select
**Run pipeline**.
WARNING:
Fork merge requests can contain malicious code that tries to steal secrets in the
parent project when the pipeline runs, even before merge. As a reviewer, you must carefully
check the changes in the merge request before triggering the pipeline. GitLab shows
a warning that you must accept before you can trigger the pipeline.
## Predefined variables available for pipelines for merge requests
When you use pipelines for merge requests, [additional predefined variables](../variables/predefined_variables.md#predefined-variables-for-merge-request-pipelines) are available to the CI/CD jobs.
These variables contain information from the associated merge request, so that you can
integrate your job with the [GitLab Merge Request API](../../api/merge_requests.md).
## Troubleshooting
### Two pipelines created when pushing to a merge request
If you are experiencing duplicated pipelines when using `rules`, take a look at
the [important differences between `rules` and `only`/`except`](../jobs/job_control.md#avoid-duplicate-pipelines),
which helps you get your starting configuration correct.
If you are seeing two pipelines when using `only/except`, please see the caveats
related to using `only/except` above (or, consider moving to `rules`).
In [GitLab 13.7](https://gitlab.com/gitlab-org/gitlab/-/issues/201845) and later,
you can add `workflow:rules` to [switch from branch pipelines to merge request pipelines](../yaml/index.md#switch-between-branch-pipelines-and-merge-request-pipelines).
After a merge request is open on the branch, the pipeline switches to a merge request pipeline.
### Two pipelines created when pushing an invalid CI configuration file
Pushing to a branch with an invalid CI configuration file can trigger
the creation of two types of failed pipelines. One pipeline is a failed merge request
pipeline, and the other is a failed branch pipeline, but both are caused by the same
invalid configuration.
## Related topics
-[Pipelines for merged results](pipelines_for_merged_results.md).
info:To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
type:reference
last_update:2019-07-03
---
# Merge Trains **(PREMIUM)**
> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/9186) in [GitLab Premium](https://about.gitlab.com/pricing/) 12.0.
> - [Squash and merge](../../user/project/merge_requests/squash_and_merge.md) support [introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/13001) in [GitLab Premium](https://about.gitlab.com/pricing/) 12.6.
For more information about why you might want to use Merge Trains, read [How merge trains keep your master green](https://about.gitlab.com/blog/2020/01/30/all-aboard-merge-trains/).
When [pipelines for merged results](pipelines_for_merged_results.md) are
enabled, the pipeline jobs run as if the changes from your source branch have already
been merged into the target branch.
However, the target branch may be changing rapidly. When you're ready to merge,
if you haven't run the pipeline in a while, the target branch may have already changed.
Merging now could introduce breaking changes.
*Merge trains* can prevent this from happening. A merge train is a queued list of merge
requests, each waiting to be merged into the target branch.
Many merge requests can be added to the train. Each merge request runs its own merged results pipeline,
which includes the changes from all of the other merge requests in *front* of it on the train.
All the pipelines run in parallel, to save time.
If the pipeline for a merge request fails, the breaking changes are not merged, and the target
branch is unaffected. The merge request is removed from the train, and all pipelines behind it restart.
If the pipeline for the merge request at the front of the train completes successfully,
the changes are merged into the target branch, and the other pipelines continue to
run.
To add a merge request to a merge train, you need [permissions](../../user/permissions.md) to push to the target branch.
Each merge train can run a maximum of **twenty** pipelines in parallel.
If more than twenty merge requests are added to the merge train, the merge requests
are queued until a slot in the merge train is free. There is no limit to the
number of merge requests that can be queued.
## Merge train example
Three merge requests (`A`, `B` and `C`) are added to a merge train in order, which
creates three merged results pipelines that run in parallel:
1. The first pipeline runs on the changes from `A` combined with the target branch.
1. The second pipeline runs on the changes from `A` and `B` combined with the target branch.
1. The third pipeline runs on the changes from `A`, `B`, and `C` combined with the target branch.
If the pipeline for `B` fails, it is removed from the train. The pipeline for
`C` restarts with the `A` and `C` changes, but without the `B` changes.
If `A` then completes successfully, it merges into the target branch, and `C` continues
to run. If more merge requests are added to the train, they now include the `A`
changes that are included in the target branch, and the `C` changes that are from
the merge request already in the train.
Read more about [how merge trains keep your master green](https://about.gitlab.com/blog/2020/01/30/all-aboard-merge-trains/).
[Merge When Pipeline Succeeds](../../user/project/merge_requests/merge_when_pipeline_succeeds.md)
is currently unavailable when Merge Trains are enabled.
See [the related issue](https://gitlab.com/gitlab-org/gitlab/-/issues/12267)
for more information.
### Merge Train Pipeline cannot be retried
When a pipeline for merge trains fails the merge request is dropped from the train and the pipeline can't be retried.
Pipelines for merge trains run on the merged result of the changes in the merge request and
the changes from other merge requests already on the train. If the merge request is dropped from the train,
the merged result is out of date and the pipeline can't be retried.
Instead, you should [add the merge request to the train](#add-a-merge-request-to-a-merge-train)
again, which triggers a new pipeline.
### Unable to add to merge train with message "The pipeline for this merge request failed."
Sometimes the **Start/Add to Merge Train** button is not available and the merge request says,
"The pipeline for this merge request failed. Please retry the job or push a new commit to fix the failure."
This issue occurs when [**Pipelines must succeed**](../../user/project/merge_requests/merge_when_pipeline_succeeds.md#only-allow-merge-requests-to-be-merged-if-the-pipeline-succeeds)
is enabled in **Settings > General > Merge requests**. This option requires that you
run a new successful pipeline before you can re-add a merge request to a merge train.
Merge trains ensure that each pipeline has succeeded before a merge happens, so
you can clear the **Pipelines must succeed** check box and keep
**Enable merge trains and pipelines for merged results** (merge trains) enabled.
If you want to keep the **Pipelines must succeed** option enabled along with Merge
Trains, create a new pipeline for merged results when this error occurs:
1. Go to the **Pipelines** tab and click **Run pipeline**.
1. Click **Start/Add to merge train when pipeline succeeds**.
See [the related issue](https://gitlab.com/gitlab-org/gitlab/-/issues/35135)
for more information.
### Merge Trains feature flag **(PREMIUM SELF)**
In [GitLab 13.6 and later](https://gitlab.com/gitlab-org/gitlab/-/issues/244831),
you can [enable or disable merge trains in the project settings](#enable-merge-trains).
In GitLab 13.5 and earlier, merge trains are automatically enabled when
[pipelines for merged results](pipelines_for_merged_results.md) are enabled.
To use pipelines for merged results without using merge trains, you can enable a
[feature flag](../../user/feature_flags.md) that blocks the merge trains feature.
[GitLab administrators with access to the GitLab Rails console](../../administration/feature_flags.md)
can enable the feature flag to disable merge trains:
```ruby
Feature.enable(:disable_merge_trains)
```
After you enable this feature flag, all existing merge trains are cancelled and
the **Start/Add to Merge Train** button no longer appears in merge requests.
To disable the feature flag, and enable merge trains again:
info:To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
type:reference
last_update:2019-07-03
---
# Pipelines for merged results **(PREMIUM)**
> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/7380) in [GitLab Premium](https://about.gitlab.com/pricing/) 11.10.
When you submit a merge request, you are requesting to merge changes from a
source branch into a target branch. By default, the CI pipeline runs jobs
against the source branch.
With *pipelines for merged results*, the pipeline runs as if the changes from
the source branch have already been merged into the target branch. The commit shown for the pipeline does not exist on the source or target branches but represents the combined target and source branches.
If the pipeline fails due to a problem in the target branch, you can wait until the
target is fixed and re-run the pipeline.
This new pipeline runs as if the source is merged with the updated target, and you
don't need to rebase.
The pipeline does not automatically run when the target branch changes. Only changes
to the source branch trigger a new pipeline. If a long time has passed since the last successful
pipeline, you may want to re-run it before merge, to ensure that the source changes
can still be successfully merged into the target.
When the merge request can't be merged, the pipeline runs against the source branch only. For example, when:
- The target branch has changes that conflict with the changes in the source branch.
- The merge request is a [**Draft** merge request](../../user/project/merge_requests/drafts.md).
In these cases, the pipeline runs as a [pipeline for merge requests](merge_request_pipelines.md)
and is labeled as `detached`. If these cases no longer exist, new pipelines
again run against the merged results.
Any user who has developer [permissions](../../user/permissions.md) can run a
pipeline for merged results.
## Prerequisites
To enable pipelines for merge results:
- You must have the [Maintainer role](../../user/permissions.md).
- You must be using [GitLab Runner](https://gitlab.com/gitlab-org/gitlab-runner) 11.9 or later.
@@ -170,8 +170,8 @@ a branch to its remote repository. To illustrate the problem, suppose you've had
This is because the previous pipeline cannot find a checkout-SHA (which is associated with the pipeline record)
from the `example` branch that the commit history has already been overwritten by the force-push.
Similarly, [Pipelines for merged results](merge_request_pipelines/pipelines_for_merged_results/index.md)
might have failed intermittently due to [the same reason](merge_request_pipelines/pipelines_for_merged_results/index.md#intermittently-pipelines-fail-by-fatal-reference-is-not-a-tree-error).
Similarly, [Pipelines for merged results](pipelines/pipelines_for_merged_results.md)
might have failed intermittently due to [the same reason](pipelines/pipelines_for_merged_results.md#intermittently-pipelines-fail-by-fatal-reference-is-not-a-tree-error).
As of GitLab 12.4, we've improved this behavior by persisting pipeline refs exclusively.
To illustrate its life cycle:
...
...
@@ -211,7 +211,7 @@ is displayed.
If the pipeline is still running, the **Merge** button is replaced with the
**Merge when pipeline succeeds** button.
If [**Merge Trains**](merge_request_pipelines/pipelines_for_merged_results/merge_trains/index.md)
If [**Merge Trains**](pipelines/merge_trains.md)
are enabled, the button is either **Add to merge train** or **Add to merge train when pipeline succeeds**. **(PREMIUM)**
#### "A CI/CD pipeline must run and be successful before merge" message
...
...
@@ -224,9 +224,9 @@ should disable **Pipelines must succeed** so you can accept merge requests.
### "The pipeline for this merge request did not complete. Push a new commit to fix the failure or check the troubleshooting documentation to see other possible actions." message
This message is shown if the [merge request pipeline](merge_request_pipelines/index.md),
@@ -328,7 +328,7 @@ runs on a [protected branch](../../user/project/protected_branches.md) or
Review all merge requests that introduce changes to the `.gitlab-ci.yml` file before you:
-[Run a pipeline in the parent project for a merge request submitted from a forked project](../merge_request_pipelines/index.md#run-pipelines-in-the-parent-project-for-merge-requests-from-a-forked-project).
-[Run a pipeline in the parent project for a merge request submitted from a forked project](../pipelines/merge_request_pipelines.md#run-pipelines-in-the-parent-project-for-merge-requests-from-a-forked-project).
- Merge the changes.
The following example shows malicious code in a `.gitlab-ci.yml` file:
@@ -125,7 +125,7 @@ There are also [Kubernetes-specific deployment variables](../../user/project/clu
These variables are available when:
- The pipelines [are merge request pipelines](../merge_request_pipelines/index.md).
- The pipelines [are merge request pipelines](../pipelines/merge_request_pipelines.md).
- The merge request is open.
| Variable | GitLab | Runner | Description |
...
...
@@ -141,12 +141,12 @@ These variables are available when:
| `CI_MERGE_REQUEST_PROJECT_URL` | 11.6 | all | The URL of the project of the merge request. For example, `http://192.168.10.15:3000/namespace/awesome-project`. |
| `CI_MERGE_REQUEST_REF_PATH` | 11.6 | all | The ref path of the merge request. For example, `refs/merge-requests/1/head`. |
| `CI_MERGE_REQUEST_SOURCE_BRANCH_NAME` | 11.6 | all | The source branch name of the merge request. |
| `CI_MERGE_REQUEST_SOURCE_BRANCH_SHA` | 11.9 | all | The HEAD SHA of the source branch of the merge request. The variable is empty in merge request pipelines. The SHA is present only in [merged results pipelines](../merge_request_pipelines/pipelines_for_merged_results/index.md). **(PREMIUM)** |
| `CI_MERGE_REQUEST_SOURCE_BRANCH_SHA` | 11.9 | all | The HEAD SHA of the source branch of the merge request. The variable is empty in merge request pipelines. The SHA is present only in [merged results pipelines](../pipelines/pipelines_for_merged_results.md). **(PREMIUM)** |
| `CI_MERGE_REQUEST_SOURCE_PROJECT_ID` | 11.6 | all | The ID of the source project of the merge request. |
| `CI_MERGE_REQUEST_SOURCE_PROJECT_PATH` | 11.6 | all | The path of the source project of the merge request. |
| `CI_MERGE_REQUEST_SOURCE_PROJECT_URL` | 11.6 | all | The URL of the source project of the merge request. |
| `CI_MERGE_REQUEST_TARGET_BRANCH_NAME` | 11.6 | all | The target branch name of the merge request. |
| `CI_MERGE_REQUEST_TARGET_BRANCH_SHA` | 11.9 | all | The HEAD SHA of the target branch of the merge request. The variable is empty in merge request pipelines. The SHA is present only in [merged results pipelines](../merge_request_pipelines/pipelines_for_merged_results/index.md). **(PREMIUM)** |
| `CI_MERGE_REQUEST_TARGET_BRANCH_SHA` | 11.9 | all | The HEAD SHA of the target branch of the merge request. The variable is empty in merge request pipelines. The SHA is present only in [merged results pipelines](../pipelines/pipelines_for_merged_results.md). **(PREMIUM)** |
| `CI_MERGE_REQUEST_TITLE` | 11.9 | all | The title of the merge request. |
| `CI_MERGE_REQUEST_EVENT_TYPE` | 12.3 | all | The event type of the merge request. Can be `detached`, `merged_result` or `merge_train`. |
| `CI_MERGE_REQUEST_DIFF_ID` | 13.7 | all | The version of the merge request diff. |
@@ -298,9 +298,9 @@ makes your pipelines run for branches and tags.
Branch pipeline status is displayed in merge requests that use the branch
as a source. However, this pipeline type does not support any features offered by
[merge request pipelines](../merge_request_pipelines/), like
[pipelines for merged results](../merge_request_pipelines/pipelines_for_merged_results/index.md)
or [merge trains](../merge_request_pipelines/pipelines_for_merged_results/merge_trains/).
[merge request pipelines](../pipelines/merge_request_pipelines.md), like
[pipelines for merged results](../pipelines/pipelines_for_merged_results.md)
or [merge trains](../pipelines/merge_trains.md).
This template intentionally avoids those features.
To [include](#include) it:
...
...
@@ -313,7 +313,7 @@ include:
The [`MergeRequest-Pipelines` template](https://gitlab.com/gitlab-org/gitlab/-/tree/master/lib/gitlab/ci/templates/Workflows/MergeRequest-Pipelines.gitlab-ci.yml)
makes your pipelines run for the default branch, tags, and
all types of merge request pipelines. Use this template if you use any of the
the [pipelines for merge requests features](../merge_request_pipelines/).
the [pipelines for merge requests features](../pipelines/merge_request_pipelines.md).
To [include](#include) it:
...
...
@@ -1335,7 +1335,7 @@ pipeline based on branch names or pipeline types.
| `chat` | For pipelines created by using a [GitLab ChatOps](../chatops/index.md) command. |
| `external` | When you use CI services other than GitLab. |
| `external_pull_requests` | When an external pull request on GitHub is created or updated (See [Pipelines for external pull requests](../ci_cd_for_external_repos/index.md#pipelines-for-external-pull-requests)). |
| `merge_requests` | For pipelines created when a merge request is created or updated. Enables [merge request pipelines](../merge_request_pipelines/index.md), [merged results pipelines](../merge_request_pipelines/pipelines_for_merged_results/index.md), and [merge trains](../merge_request_pipelines/pipelines_for_merged_results/merge_trains/index.md). |
| `merge_requests` | For pipelines created when a merge request is created or updated. Enables [merge request pipelines](../pipelines/merge_request_pipelines.md), [merged results pipelines](../pipelines/pipelines_for_merged_results.md), and [merge trains](../pipelines/merge_trains.md). |
| `pipelines` | For [multi-project pipelines](../multi_project_pipelines.md) created by [using the API with `CI_JOB_TOKEN`](../multi_project_pipelines.md#create-multi-project-pipelines-by-using-the-api), or the [`trigger`](#trigger) keyword. |
| `pushes` | For pipelines triggered by a `git push` event, including for branches and tags. |
| `schedules` | For [scheduled pipelines](../pipelines/schedules.md). |
...
...
@@ -4776,7 +4776,7 @@ pushing multiple changes in a single `git push` invocation.
This limitation does not affect any of the updated merge request pipelines.
All updated merge requests have a pipeline created when using
[pipelines for merge requests](../merge_request_pipelines/index.md).
[pipelines for merge requests](../pipelines/merge_request_pipelines.md).
[very specific cases](https://about.gitlab.com/handbook/engineering/workflow/#criteria-for-merging-during-broken-master).
For other cases, follow these [handbook instructions](https://about.gitlab.com/handbook/engineering/workflow/#merging-during-broken-master).
- If the **latest [Pipeline for Merged Results](../ci/merge_request_pipelines/pipelines_for_merged_results/#pipelines-for-merged-results)** finished less than 2 hours ago, you
- If the **latest [Pipeline for Merged Results](../ci/pipelines/pipelines_for_merged_results.md)** finished less than 2 hours ago, you
might merge without starting a new pipeline as the merge request is close
enough to `main`.
- When you set the MR to "Merge When Pipeline Succeeds", you should take over
...
...
@@ -444,7 +444,7 @@ Merge Results against the latest `main` at the time of the pipeline creation.
WARNING:
**Review all changes thoroughly for malicious code before starting a
[Pipeline for Merged Results](../ci/merge_request_pipelines/index.md#run-pipelines-in-the-parent-project-for-merge-requests-from-a-forked-project).**
[Pipeline for Merged Results](../ci/pipelines/merge_request_pipelines.md#run-pipelines-in-the-parent-project-for-merge-requests-from-a-forked-project).**
When reviewing merge requests added by wider community contributors:
-[Mirroring with Perforce Helix via Git Fusion](../user/project/repository/repository_mirroring.md#mirroring-with-perforce-helix-via-git-fusion)
- Runners:
- Run pipelines in the parent project [for merge requests from a forked project](../ci/merge_request_pipelines/index.md#run-pipelines-in-the-parent-project-for-merge-requests-from-a-forked-project)
- Run pipelines in the parent project [for merge requests from a forked project](../ci/pipelines/merge_request_pipelines.md#run-pipelines-in-the-parent-project-for-merge-requests-from-a-forked-project)
- A project built in Rails that uses RSpec for testing.
- CI/CD configured to:
- Use a Docker image with Ruby available.
- Use [Pipelines for merge requests](../../../ci/merge_request_pipelines/index.md#configure-pipelines-for-merge-requests)
-[Pipelines for Merged Results](../../../ci/merge_request_pipelines/pipelines_for_merged_results/index.md#enable-pipelines-for-merged-results)
- Use [Pipelines for merge requests](../../../ci/pipelines/merge_request_pipelines.md#configure-pipelines-for-merge-requests)
-[Pipelines for Merged Results](../../../ci/pipelines/pipelines_for_merged_results.md#enable-pipelines-for-merged-results)
enabled in the project settings.
- A Docker image with Ruby available. The template uses `image: ruby:2.6` by default, but you [can override](../../../ci/yaml/includes.md#overriding-external-template-values) this.
@@ -23,7 +23,7 @@ or link to useful information directly from merge requests:
| [License Compliance](../../compliance/license_compliance/index.md)**(ULTIMATE)** | Manage the licenses of your dependencies. |
| [Metrics Reports](../../../ci/metrics_reports.md)**(PREMIUM)** | Display the Metrics Report on the merge request so that it's fast and easy to identify changes to important metrics. |
| [Multi-Project pipelines](../../../ci/multi_project_pipelines.md)**(PREMIUM)** | When you set up GitLab CI/CD across multiple projects, you can visualize the entire pipeline, including all cross-project interdependencies. |
| [Pipelines for merge requests](../../../ci/merge_request_pipelines/index.md) | Customize a specific pipeline structure for merge requests in order to speed the cycle up by running only important jobs. |
| [Pipelines for merge requests](../../../ci/pipelines/merge_request_pipelines.md) | Customize a specific pipeline structure for merge requests in order to speed the cycle up by running only important jobs. |
| [Pipeline Graphs](../../../ci/pipelines/index.md#visualize-pipelines) | View the status of pipelines within the merge request, including the deployment process. |
| [Test Coverage visualization](test_coverage_visualization.md) | See test coverage results for merge requests, within the file diff. |
@@ -73,7 +73,7 @@ threads. Some quick actions might not be available to all subscription tiers.
| `/iteration *iteration:"iteration name"` | **{check-circle}** Yes | **{dotted-circle}** No | **{dotted-circle}** No | Set iteration. For example, to set the `Late in July` iteration: `/iteration *iteration:"Late in July"` ([introduced in GitLab 13.1](https://gitlab.com/gitlab-org/gitlab/-/issues/196795)). |
| `/label ~label1 ~label2` | **{check-circle}** Yes | **{check-circle}** Yes | **{check-circle}** Yes | Add one or more labels. Label names can also start without a tilde (`~`), but mixed syntax is not supported. |
| `/lock` | **{check-circle}** Yes | **{check-circle}** Yes | **{dotted-circle}** No | Lock the discussions. |
| `/merge` | **{dotted-circle}** No | **{check-circle}** Yes | **{dotted-circle}** No | Merge changes. Depending on the project setting, this may be [when the pipeline succeeds](merge_requests/merge_when_pipeline_succeeds.md), or adding to a [Merge Train](../../ci/merge_request_pipelines/pipelines_for_merged_results/merge_trains/index.md). |
| `/merge` | **{dotted-circle}** No | **{check-circle}** Yes | **{dotted-circle}** No | Merge changes. Depending on the project setting, this may be [when the pipeline succeeds](merge_requests/merge_when_pipeline_succeeds.md), or adding to a [Merge Train](../../ci/pipelines/merge_trains.md). |
| `/milestone %milestone` | **{check-circle}** Yes | **{check-circle}** Yes | **{dotted-circle}** No | Set milestone. |
| `/move <path/to/project>` | **{check-circle}** Yes | **{dotted-circle}** No | **{dotted-circle}** No | Move this issue to another project. |
| `/parent_epic <epic>` | **{dotted-circle}** No | **{dotted-circle}** No | **{check-circle}** Yes | Set parent epic to `<epic>`. The `<epic>` value should be in the format of `&epic`, `group&epic`, or a URL to an epic ([introduced in GitLab 12.1](https://gitlab.com/gitlab-org/gitlab/-/issues/10556)). |
=s_('ProjectSettings|When pipelines for merge requests are enabled in the CI/CD configuration file, pipelines validate the combined results of the source and target branches. %{link_start}How to configure pipelines for merge requests?%{link_end}').html_safe%{link_start: configuring_pipelines_for_merge_requests_help_link_start,link_end: '</a>'.html_safe}
=s_('ProjectSettings|Merge requests approved for merge are queued, and pipelines validate the combined results of the source and target branches before merge. %{link_start}What are merge trains?%{link_end}').html_safe%{link_start: merge_trains_help_link_start,link_end: '</a>'.html_safe}
