Amazon CodeCatalyst is no longer open to new customers. Existing customers can continue to use the service as normal. For more information, see [How to migrate from CodeCatalyst](migration.md).

# Usage guidelines for triggers and branches
<a name="workflows-add-trigger-considerations"></a>

This section describes some of the main guidelines when setting up Amazon CodeCatalyst triggers that include branches.

For more information about triggers, see [Starting a workflow run automatically using triggers](workflows-add-trigger.md).
+ **Guideline 1:** For both push and pull request triggers, if you are going to specify a branch, you must specify the destination (or 'to') branch in the trigger configuration. Never specify the source (or 'from') branch.

  In the following example, a push from any branch to `main` activates the workflow.

  ```
  Triggers:
    - Type: PUSH
      Branches:
        - main
  ```

  In the following example, a pull request from any branch into `main` activates the workflow.

  ```
  Triggers:
    - Type: PULLREQUEST
      Branches:
        - main
      Events:
        - OPEN
        - REVISION
  ```
+ **Guideline 2:** For push triggers, after the workflow is activated, the workflow will run using the workflow definition file and source files in the *destination* branch.
+ **Guideline 3:** For pull request triggers, after the workflow is activated, the workflow will run using the workflow definition file and source files in the *source* branch (even though you specified the destination branch in the trigger configuration).
+ **Guideline 4:** The exact same trigger in one branch might not run in another branch.

  Consider the following push trigger:

  ```
  Triggers:
    - Type: PUSH
      Branches:
        - main
  ```

  If the workflow definition file containing this trigger exists in `main` and gets cloned to `test`, the workflow will never start automatically using the files in `test` (although you could start the workflow *manually* to have it use the files in `test`). Review **Guideline 2** to understand why the workflow will never run automatically using the files in `test`.

  Consider also the following pull request trigger:

  ```
  Triggers:
    - Type: PULLREQUEST
      Branches:
        - main
      Events:
        - OPEN
        - REVISION
  ```

  If the workflow definition file containing this trigger exists in `main`, the workflow will never run using the files in `main`. (However, if you create a `test` branch off of `main`, the workflow will run using the files in `test`.) Review **Guideline 3** to understand why.