query --output jsonproto produces invalid json when multiple objects are returned

[novas0x2a]

Description of the bug:

bazel query --output jsonproto //pkg1:target+//pkg2:target

produces json that looks like:

{
  "type": "RULE",
  "rule": {...}
}{
  "type": "RULE",
  "rule": {...}
}

i.e. it produces a stream of json objects without the necessary [] wrapper to make it an array. Some tools handle this (e.g. jq has no problem with it) but other parsers (like python's json) fail with

json.decoder.JSONDecodeError: Extra data: line 240 column 2 (char 6270)

I suspect this is the same problem as #14209

Which category does this issue belong to?

CLI

What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

git clone https://github.com/bazelbuild/bazel repro
cd repro
git checkout 7.0.0-pre.20230906.2
bazel query --output jsonproto //tools/aquery_differ:aquery_differ+//tools/aquery_differ:aquery_differ_test | python -m json.tool

produces

Extra data: line 241 column 2 (char 6533)

Which operating system are you running Bazel on?

linux

What is the output of bazel info release?

release 6.3.2

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse master; git rev-parse HEAD ?

No response

Is this a regression? If yes, please try to identify the Bazel commit where the bug was introduced.

No response

Have you found anything relevant by searching the web?

No response

Any other information, logs, or outputs that you want to share?

No response

[brentleyjones]

Can you try 6.4.0rc1, which has this a8b2543?

[brentleyjones]

Key thing: #18701 (comment)

It's now called streamed_jsonproto and it's in NDJSON format.

[novas0x2a]

It's sort of a minor nit, but maybe it should be called streamed_ndjsonproto? I'm not sure I would have recognized the output as ndjson if it hadn't been mentioned above. Loading it with a json parser requires a bit of additional work, and googling "ndjson python" led me to --json-lines. Knowing the name of the format made it a lot easier to figure it out. It does work, though:

$ bazel info release
release 6.4.0rc1
$ bazel query --output streamed_jsonproto //tools/aquery_differ:aquery_differ+//tools/aquery_differ:aquery_differ_test | python -mjson.tool --json-lines | head -n5
Loading: 0 packages loaded
Loading: 0 packages loaded
{
    "type": "RULE",
    "rule": {
        "name": "//tools/aquery_differ:aquery_differ",
        "ruleClass": "py_binary",

[zhengwei143]

I'm leaning for this to be a documentation fix (https://bazel.build/query/language#output-formats).