[3.5] add more debug info for opening WAL files failure

[ahrtr]

Backport #14862 to 3.5.

Related issue: #14851

Signed-off-by: Benjamin Wang wachao@vmware.com

Please read https://github.com/etcd-io/etcd/blob/main/CONTRIBUTING.md#contribution-flow.

[ahrtr]

cc @serathius

[serathius]

Not a big fan of backporting a feature, especially one that breaks backward compatibility. Returned error will no longer be ErrFileNotFound, so all the checks err == ErrFileNotFound need to be changed to error.Is(err, ErrFileNotFound).

In my opinion the benefits don't outweigh the risk of something breaking.

[ahrtr]

all the checks err == ErrFileNotFound need to be changed to error.Is(err, ErrFileNotFound)

Already updated.

Not a big fan of backporting a feature, especially one that breaks backward compatibility.

Note that the reason why I submitted this PR is that it's hard to tell where is the error coming from in #14851. Since we will maintain 3.5 for a long time, it's definitely worthwhile to add such debug info.

In my opinion the benefits don't outweigh the risk of something breaking.

I don't get what's the risk you are talking about. It only affects unit test.