The snap daemon, snapd, is the background service that manages and maintains your snaps.
Occasionally, snapd may develop an issue or bug that is only apparent on specific devices or in specific circumstances. A fix will be developed as soon as possible, but we may need to test a fix on those devices or installations before it can be merged and more widely distributed.
In such cases, a patched snapd can be provided via a pull request and installed by those affected so they can report on whether it solves the original issue. This process is outlined below.
Access GitHub
The snap daemon, and its associated tools and projects are hosted GitHub (see https://github.com/snapcore). The snapd repository contains all the branches, pull requests, automated tests and discussions applicable to snapd.
A fix will typically be contained within a pull request prior to it being merged. The snapd repository is configured to automatically test and build an approved pull request, creating what is called an artifact that can be downloaded and tested locally.
A test release, especially from a pull request, should only be installed in a test environment as its behaviour could obviously be unpredictable. To install a test release, you will first need a GitHub account and you will need to be logged in from your favourite web browser.
Locate the pull request
This location of the pull request will usually have been communicated separately, but open pull requests can be found linked to from the snapd repository (https://github.com/snapcore/snapd/pulls). Each pull request has a unique number identifier, such as #11085.
With the pull request opened in your web browser, select the Checks tab. This contains the output from the automated tests and build processes initiated when an approved pull request is created or updated. If a pull request has only recently been submitted or updated, it can take some time for this page to become fully populated.
Download the artifact
Select Tests from the menu on the left. This will take you to the Actions tab for the snapd repository showing the test runs for the previously selected pull request. Scroll to the bottom of this list and you’ll see the artifacts section containing a link to the downloadable snap-files zip archive (GitHub stores build logs and artifacts for 90 days):
Click on snap-files to download the archive.
Install the test version
First, unzip the file we downloaded:
$ unzip snap-files.zip
Archive: snap-files.zip
inflating: snapd_2.53.2+git6345be5.6345be5-dirty_amd64.snap
This resultant snap for the specific pull request we selected earlier can now be installed with snap’s dangerous mode:
$ snap install --dangerous snapd_2.53.2+git6345be5.6345be5-dirty_amd64.snap
2021-11-24T13:06:46Z INFO Waiting for automatic snapd restart...
snapd 2.53.2+git6345be5.6345be5-dirty installed
At this point, the fix for the issue or bug can now be tested and the results reported.
To revert the local installation to an official snapd release, simply refresh the snapd snap to its stable channel:
$ snap refresh snapd --stable --amend