Merge branch 'add-docs-for-collapsing-generated-files' into 'master'

Add docs for collapsing generated files

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/141452



Merged-by: Phillip Wells <pwells@gitlab.com>
Approved-by: Amy Qualls <aqualls@gitlab.com>
Approved-by: Phillip Wells <pwells@gitlab.com>
Reviewed-by: Sincheol (David) Kim <dkim@gitlab.com>
Reviewed-by: Phillip Wells <pwells@gitlab.com>
Co-authored-by: David Kim <dkim@gitlab.com>
Co-authored-by: Amy Qualls <aqualls@gitlab.com>
Co-authored-by: Kai Armstrong <karmstrong@gitlab.com>

doc/user/project/merge_requests/changes.md

@@ -34,6 +34,66 @@ To view the diff of changes included in a merge request:
 Files with many changes are collapsed to improve performance. GitLab displays the message:
 **Some changes are not shown**. To view the changes for that file, select **Expand file**.
 
+### Collapse generated files **(FREE SELF)**
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/140180) in GitLab 16.8 [with a flag](../../../administration/feature_flags.md) named `collapse_generated_diff_files`. Disabled by default.
+
+FLAG:
+On self-managed GitLab, by default this feature is not available. To make it available,
+an administrator can [enable the feature flag](../../../administration/feature_flags.md)
+named `collapse_generated_diff_files`.
+On GitLab.com, this feature is not available.
+
+To help reviewers focus on the files needed to perform a code review, GitLab collapses
+several common types of generated files. These files are collapsed by default, because
+they are unlikely to require code reviews:
+
+1. Files with `.nib`, `.xcworkspacedata`, or `.xcurserstate` extensions.
+1. Package lock files such as `package-lock.json` or `Gopkg.lock`.
+1. Files in the `node_modules` folder.
+1. Minified `js` or `css` files.
+1. Source map reference files.
+1. Generated Go files, including the generated files by protocol buffer compiler.
+
+If you want to automatically collapse additional files or file types, you can use the `gitlab-generated` attribute. To mark or unmark certain files/paths as generated if the default doesn't suit
+your preference. See [overriding syntax highlighting](../highlighting.md#override-syntax-highlighting-for-a-file-type) for more
+detail on how to use override attributes.
+
+#### View a collapsed file
+
+1. On the left sidebar, select **Search or go to** and find your project.
+1. Select **Code > Merge requests** and find your merge request.
+1. Below the merge request title, select **Changes**.
+1. Find the file you want to view, and select **Expand file**.
+
+#### Configure collapse behavior for a file type
+
+To change the default collapse behavior for a file type:
+
+1. If a `.gitattributes` file does not exist in the root directory of your project,
+   create a blank file with this name.
+1. For each file type you want to modify, add a line to the `.gitattributes` file
+   declaring the file extension and your desired behavior:
+
+   ```conf
+   # Collapse all files with a .txt extension
+   *.txt gitlab-generated
+
+   # Collapse all files within the docs directory
+   docs/** gitlab-generated
+
+   # Do not collapse package-lock.json
+   package-json -gitlab-generated
+   ```
+
+1. Commit, push, and merge your changes into your default branch.
+
+After the changes merge into your [default branch](../repository/branches/default.md),
+all files of this type in your project use this behavior in merge requests.
+
+For technical details about how generated files are detected, see the
+[`go-enry`](https://github.com/go-enry/go-enry/blob/master/data/generated.go) repository.
+
 ## Show one file at a time
 
 For larger merge requests, you can review one file at a time. You can change this setting