Invalid JSON output when no rows

[gravis]

sqlite-utils query generates a JSON output with the result from the query:

[{...},{...}]

If no rows are returned by the query, I'm expecting an empty JSON array:

[]

But actually I'm getting an empty string. To be consistent, the output should be [] when the request succeeds (return code == 0).

[simonw]

Good catch, thanks.

[simonw]

The bug is in this code:

sqlite-utils/sqlite_utils/cli.py

Lines 2205 to 2227 in 77c240d

	def output_rows(iterator, headers, nl, arrays, json_cols):
	# We have to iterate two-at-a-time so we can know if we
	# should output a trailing comma or if we have reached
	# the last row.
	current_iter, next_iter = itertools.tee(iterator, 2)
	next(next_iter, None)
	first = True
	for row, next_row in itertools.zip_longest(current_iter, next_iter):
	is_last = next_row is None
	data = row
	if json_cols:
	# Any value that is a valid JSON string should be treated as JSON
	data = [maybe_json(value) for value in data]
	if not arrays:
	data = dict(zip(headers, data))
	line = "{firstchar}{serialized}{maybecomma}{lastchar}".format(
	firstchar=("[" if first else " ") if not nl else "",
	serialized=json.dumps(data, default=json_binary),
	maybecomma="," if (not nl and not is_last) else "",
	lastchar="]" if (is_last and not nl) else "",
	)
	yield line
	first = False

[gravis]

Wow, that was fast! Thank you!