I've had to change the output of git annex metadata --json. The old output looked like this:

{"command":"metadata","file":"foo","key":"...","author":["bar"],...,"note":"...","success":true}

That was not good, because it didn't separate the metadata fields from the rest of the JSON object. What if a metadata field is named "note" or "success"? It would collide with the other "note" and "success" in the JSON.

So, changed this to a new format, which moves the metadata fields into a "fields" object:

{"command":"metadata","file":"foo","key":"...","fields":{"author":["bar"],...},"note":"...","success":true}

I don't like breaking backwards compatability of JSON output, but in this case I could see no real alternative. I don't know if anyone is using metadata --batch anyway. If you are and this will cause a problem, get in touch.

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While making that change, I also improved the JSON output layer, so it can use Aeson. Update: And switched everything over to using Aeson, so git-annex no longer depends on two different JSON libraries.

This let me use Aeson to generate the "fields" object for metadata --json. And it was also easy enough to use Aeson to parse the output of that command (and some simplified forms of it).

So, I've laid the groundwork for git annex metadata --batch today.