Saving cache on job failure in GitHub Actions - github

Question

I am using the GitHub cache action, but I noticed that the no cache will be created if the job fails. From the docs:
If the job completes successfully, the action creates a new cache with the contents of the path directory.
A stripped down version of my workflow YAML file:
name: Build
on: [push]
jobs:
deploy:
runs-on: ubuntu-latest
steps:
- name: Checkout
uses: actions/checkout#v1
- name: Setup Node.js
uses: actions/setup-node#master
with:
node-version: '10.x'
- name: Get yarn cache path
id: yarn-cache-dir-path
run: echo "::set-output name=dir::$(yarn cache dir)"
- name: Restore yarn cache
uses: actions/cache#v1
id: yarn-cache
with:
path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
restore-keys: |
${{ runner.os }}-yarn-
- name: Install yarn dependencies
run: yarn install
- name: Build
run: yarn build
I noticed that if my Build step fails the cache post-step will be skipped unnecessarily, which causes the installed dependencies to not be cached. This requires subsequent runs to download dependencies again, slowing down the job.
Is there a way to always cache the dependencies, even when the build step fails?

Answer 1

In the official version of the action, no it's not possible to cache dependencies if the build fails. See this line in the cache action's manifest:
runs:
using: 'node12'
main: 'dist/restore/index.js'
post: 'dist/save/index.js'
post-if: 'success()'
It will only run the post-step if the job succeeds. I don't know the original reasoning for this, but there are a few issues opened around this idea. In this issue a user forked the action to change the post-if to always(), which may be what you're after, assuming you're willing to run an unofficial action.