---
title: "revision(_:)"
framework: swift-package-manager
role: symbol
role_heading: Type Method
path: "swift-package-manager/documentation/packagedescription/package/dependency/requirement-swift.enum/revision(_:)"
---

# revision(_:)

Returns a requirement for a source control revision such as the hash of a commit.

## Declaration

```swift
static func revision(_ ref: String) -> Package.Dependency.Requirement
```

## Parameters

- `ref`: The Git revision, usually a commit hash.

## Discussion

Discussion Note that packages that use commit-based dependency requirements can’t be depended upon by packages that use version-based dependency requirements; you should remove commit-based dependency requirements before publishing a version of your package. The following example defines a version requirement for a specific commit hash. .revision(“e74b07278b926c9ec6f9643455ea00d1ce04a021”)