update

doc/todo/api_for_telling_when_nonexistant_or_non_git_files_passed.mdwn

@@ -11,3 +11,17 @@ it to skip processing certian files.
 Perhaps something like `--json-error-unmatch` which would make it output
 an additional line with a JSON record indicating that git ls-files
 --error-unmatch had errored out.
+
+Or `--json` could enable this additional JSON record output.
+The advantage would be that datalad would not need to check the git-annex
+version to see if the option is supported. It would need to output a
+JSON record even when git-ls-files did not fail. Perhaps something like
+this:
+
+	{"git-ls-files exit status": 0}
+	{"git-ls-files exit-status": 1}
+
+This does risk breaking things that parse the existing JSON and fall
+over on the new record, but I think git-annex should be free to add new
+records and fields to its JSON output in general, and it has probably
+at least added new fields before. --[[Joey]]