Should configure ccache before restore cache about setup-ccache-action

[zhongfly]

One thing more, don't run updatePackgerIndex if install_ccache is false.

[Chocobo1]

If set cache_dir to another place,it will make restore cache never success.

I resolved it in 64fc5fd.
Thanks for reporting!

[zhongfly]

Still have problem with env:
example:cache_dir=$GITHUB_WORKSPACE/.ccache
This action will save cache in path /__w/my-repo-name/my-repo-name/.ccache(run job in a docker image) or /home/runner/work/my-repo-name/my-repo-name/.ccache, but restore cache using $GITHUB_WORKSPACE/.ccache.
So restore will always fail.
You can find $GITHUB_WORKSPACE in https://docs.github.com/en/actions/learn-github-actions/variables#default-environment-variables

@Chocobo1 my pr can fix this, but 64fc5fd can't.
In my opinion, #19 simply solves the problem and avoids the bugs that restore cache and save cache use different paths

[Chocobo1]

example:cache_dir=$GITHUB_WORKSPACE/.ccache

Strictly speaking it is invalid to use environment variables here. Use cache_dir=${{ github.workspace }}/.ccache instead.
Here we are not invoking ccache via shell but from "github actions" context so environment variables aren't resolved (at least github actions chooses not to).
However, I do agree that this is a bit unexpected for the common users. I'll ponder on it.

In my opinion, #19 simply solves the problem and avoids the bugs that restore cache and save cache use different paths

I'm concerned that if the ccache config resides within the cache path and after cache restore it will overwritten the configuration. I don't consider it correct.

[Chocobo1]

Strictly speaking it is invalid to use environment variables here. Use cache_dir=${{ github.workspace }}/.ccache instead.
Here we are not invoking ccache via shell but from "github actions" context so environment variables aren't resolved (at least github actions chooses not to).

I think this is the relevant documentation:
https://docs.github.com/en/actions/learn-github-actions/variables#using-the-env-context-to-access-environment-variable-values

The run steps in a workflow, or in a referenced action, are processed by a runner. As a result, you can use runner environment variables here, using the appropriate syntax for the shell you are using on the runner - for example, $NAME for the bash shell on a Linux runner, or $env:NAME for PowerShell on a Windows runner. In most cases you can also use contexts, with the syntax ${{ CONTEXT.PROPERTY }}, to access the same value. The difference is that the context will be interpolated and replaced by a string before the job is sent to a runner.

However, you cannot use runner environment variables in parts of a workflow that are processed by GitHub Actions and are not sent to the runner. Instead, you must use contexts.

And as I mentioned, setup-ccache-action is processed by GitHub Actions not via a runner/shell.

https://docs.github.com/en/actions/learn-github-actions/variables#default-environment-variables

However, most of the default variables have a corresponding, and similarly named, context property. For example, the value of the GITHUB_REF variable can be read during workflow processing using the ${{ github.ref }} context property.

Also it seems to me that github have already known this (downside) and decided to provide both context properties and runner env variables.

[zhongfly]

Strictly speaking it is invalid to use environment variables here. Use cache_dir=${{ github.workspace }}/.ccache instead.

In most cases you can also use contexts, with the syntax ${{ CONTEXT.PROPERTY }}, to access the same value.

Yes, but $GITHUB_WORKSPACE and ${{ github.workspace}} are different for job running in a container.
see this actions/checkout#785 and actions/runner#2058

Example:

name: archlinux

on: workflow_dispatch

jobs:
  build:
    runs-on: ubuntu-latest
    container:
      image: archlinux/archlinux:base-devel
    steps:
      - run: echo "${{ github.workspace }}" ; echo "$GITHUB_WORKSPACE"

${{ github.workspace }} is /home/runner/work/..., but $GITHUB_WORKSPACE is /__w/...

Github action does have some weirdness to it.

[zhongfly]

I think the main problem is that the paths to save cache and restore cache have to be exactly the same in terms of characters.
Either both prioritize the value of ccache_options or both prioritize the value in the config file. Instead of using different values as it is now

setup-ccache-action/src/post.ts

Line 85 in 3c66724

const paths = [Path.normalize(await Utils.getCachePath())];

setup-ccache-action/src/main.ts

Line 146 in 3c66724

return [Path.normalize(userDefinedDir ?? await Utils.getCachePath())];

[Chocobo1]

${{ github.workspace }} is /home/runner/work/..., but $GITHUB_WORKSPACE is /__w/...

Github action does have some weirdness to it.

True and they still haven't address it yet...

Not sure if you are still looking for a workaround but just in case, perhaps the following will work:

  # export variable
  - run: echo "GITHUB_WORKSPACE=$GITHUB_WORKSPACE" >> $GITHUB_ENV
  # use variable
  - name: Set up ccache
    uses: Chocobo1/setup-ccache-action@v1
    with:
      ccache_options: |
        cache_dir=${{ env.GITHUB_WORKSPACE }}/.ccache

[zhongfly]

Earlier you talked about the possibility of overwriting the config file when restoring cache, so set the option after restoring.So maybe we can set the option cache_dir both before and after restore