I have about 40 git repositories, most of which have a `.git-blame-ignore-revs` file for using with `git blame`. So, instead of locally configuring each of them with `blame.ignorerevsfile=.git-blame-ignore-revs`, I applied it to my *global* git config.

However, the few repositories which do *not* have such a file are impacted by it: running `git blame` on them results in `fatal: could not open object name list: .git-blame-ignore-revs`.

Is there a way to tell git to read such file *if it exists*, ignoring it otherwise? That would be ideal: simple to setup, yet unobtrusive if no such file exists.

Note: another reason why having an *optional* `.git-blame-ignore-revs` file is useful, is that virtually all git repositories are created *without* such a file, and only later it is added. However, when bisecting old commits, we may end up returning to a point *before* the file exists, and then we have to `touch` it, finish bisecting, then remove it again to be able to return to the HEAD commit. Even if I use a *local* config for the file, this extremely annoying situation will still happen. For that reason, I do believe the default behavior should be to ignore the file if it does not exist.