Several behavioral differences exist between Artifact actions `v3` and below vs `v4`. This document outlines common scenarios in `v3`, and how they would be handled in `v4`.
## Multiple uploads to the same named Artifact
In `v3`, Artifacts are _mutable_ so it's possible to write workflow scenarios where multiple jobs upload to the same Artifact like so:
In v4, Artifacts are immutable (unless deleted). So you must change each of the uploaded Artifacts to have a different name and filter the downloads by name to achieve the same effect:
In `v4`, the new `pattern:` input will filter the downloaded Artifacts to match the name specified. The new `merge-multiple:` input will support downloading multiple Artifacts to the same directory. If the files within the Artifacts have the same name, the last writer wins.
In `v3`, the contents of an Artifact were mutable so something like the following was possible:
```yaml
jobs:
upload:
runs-on: ubuntu-latest
steps:
- name: Create a file
run: echo "hello world" > my-file.txt
- name: Upload Artifact
uses: actions/upload-artifact@v3
with:
name: my-artifact # NOTE: same artifact name
path: my-file.txt
upload-again:
needs: upload
runs-on: ubuntu-latest
steps:
- name: Create a different file
run: echo "goodbye world" > my-file.txt
- name: Upload Artifact
uses: actions/upload-artifact@v3
with:
name: my-artifact # NOTE: same artifact name
path: my-file.txt
```
The resulting `my-file.txt` in `my-artifact` will have "goodbye world" as the content.
In `v4`, Artifacts are immutable unless deleted. To achieve this same behavior, you can use `overwrite: true` to delete the Artifact before a new one is created:
```diff
jobs:
upload:
runs-on: ubuntu-latest
steps:
- name: Create a file
run: echo "hello world" > my-file.txt
- name: Upload Artifact
- uses: actions/upload-artifact@v3
+ uses: actions/upload-artifact@v4
with:
name: my-artifact # NOTE: same artifact name
path: my-file.txt
upload-again:
needs: upload
runs-on: ubuntu-latest
steps:
- name: Create a different file
run: echo "goodbye world" > my-file.txt
- name: Upload Artifact
- uses: actions/upload-artifact@v3
+ uses: actions/upload-artifact@v4
with:
name: my-artifact # NOTE: same artifact name
path: my-file.txt
+ overwrite: true
```
Note that this will create an _entirely_ new Artifact, with a different ID from the previous.
## Merging multiple artifacts
In `v3`, multiple uploads from multiple jobs could be done to the same Artifact. This would result in a single archive, which could be useful for sending to upstream systems outside of Actions via API or UI downloads.
Note that this will download all artifacts to a temporary directory and reupload them as a single artifact. For more information on inputs and other use cases for `actions/upload-artifact/merge@v4`, see [the action documentation](https://github.com/actions/upload-artifact/blob/main/merge/README.md).
