[CI] Restore cache failed: Dependencies file is not found

[RainbowMango]

What would you like to be added:
Investigate if there is something wrong with the GitHub Action to address the warning:

Restore cache failed: Dependencies file is not found in /home/runner/work/karmada/karmada. Supported file pattern: go.sum

You can get the warning from here: https://github.com/karmada-io/karmada/actions/runs/8957867986

References:
actions/setup-go#427

Why is this needed:

[RainbowMango]

cc @liangyuanpeng @zhzhuang-zju

[liangyuanpeng]

Tracing upstream issue:

• Dependencies file is not found. Supported file pattern: go.sum actions/setup-go#476

[liangyuanpeng]

seems like the reason is this workflow have a specially workspace path:

karmada/.github/workflows/ci.yml

Line 50 in 5e1191f

go-version-file: ${{ env.GOPATH }}/src/github.com/karmada-io/karmada/go.mod

[zhzhuang-zju]

Refer to https://github.com/actions/setup-go/blob/cdcb36043654635271a94b9a6d1392de5bb323a7/src/cache-restore.ts#L52-L65, when cache restore occurs, it looks for the go.sum file at the next level of the directory ${{github.workspace}} and reports an error if it is not found. In our CI scenario, variable ${{github.workspace}} is /home/runner/work/karmada/karmada, but the path of file go.sum is /home/runner/work/karmada/karmada/src/github.com/karmada-io/karmada/go.sum, so the action cannot find file go.sum and print the warning log.

The reason for the inconsistency of the directory is what @liangyuanpeng said, this workflow have a specially workspace path. By tracing the history of the code, this specially workspace path was introduced in #1221 to solve the problem of ci failing to intercept the PR which introduced API change but without deepcopy update.

[RainbowMango]

Thanks for the details analysis, do we have a solution to fix it?

[zhzhuang-zju]

Thanks for the details analysis, do we have a solution to fix it?

The easiest way is to remove the specially workspace path. I gave it a try and submitting a PR which introduced API change but without deepcopy update and didn't end up with the problem described in #1221, so I guess I'll have to look into the reasons for adding the specially workspace path on PR #1221.

[liangyuanpeng]

actions/setup-go#427 (comment)
as second choice

[zhzhuang-zju]

The easiest way is to remove the specially workspace path. I gave it a try and submitting a PR which introduced API change but without deepcopy update and didn't end up with the problem described in #1221, so I guess I'll have to look into the reasons for adding the specially workspace path on PR #1221.

Through experimentation, directly deleting the specially workspace path will not affect the functionality of the CI, as can be seen in https://github.com/zhzhuang-zju/karmada/actions/runs/8966655310/job/24622621482.

The specific reason for this is the addition of this code inside the file hack/update-codegen.sh

karmada/hack/update-codegen.sh

Lines 43 to 45 in c7c8f49

	source "${REPO_ROOT}"/hack/util.sh
	util:create_gopath_tree "${REPO_ROOT}" "${go_path}"
	export GOPATH="${go_path}"

This code sets the variable ${{GOPATH}} to a path under ${REPO_ROOT}, so CI doesn't need to run under path ${{ env.GOPATH }}/src/github.com/karmada-io/karmada

cc @RainbowMango @liangyuanpeng

[RainbowMango]

Good job! @zhzhuang-zju
#1221 fixed the issue of CI, but with #1731, we don't need it anymore.
Can you send a PR for this?

[zhzhuang-zju]

/assign