Error when generating/serializing keys with multilines and colon

[eginez]

Hello there

I wanted to report that a key containing a colon : followed by new line chars \n does not seem to be parsing correctly. For example the following test case reproduces the error

    @Test(expected = JsonParseException.class)
    public void testYamlMultiLineNotCanonical() throws Exception {
        String key = "SomeKey:\n\nOtherLine";
        ObjectMapper jsonMapper = new ObjectMapper();
        ObjectNode jsonRoot = jsonMapper.createObjectNode();
        jsonRoot.put(key, 302);

        YAMLFactory yamlFactory = new YAMLFactory();
        ObjectMapper yamlObjectMapper = new ObjectMapper(yamlFactory);
        yamlObjectMapper.configure(JsonParser.Feature.STRICT_DUPLICATE_DETECTION, true);
        StringWriter swriter = new StringWriter();

        yamlObjectMapper.writeValue(swriter, jsonRoot);

        ObjectMapper readMapper =  new ObjectMapper(yamlFactory);
        ObjectNode readJsonRoot = (ObjectNode) readMapper.readTree(swriter.toString());
        Assert.assertEquals(readJsonRoot.get(key).asInt(),302 );
    }

I would have expected the parser to quote the key as \n and : are supported yaml content.

There is work around for this: Force canonical output.

        yamlFactory.configure(YAMLGenerator.Feature.CANONICAL_OUTPUT, true);

That however could have other side effects. Maybe I am missing some other configuration that would do the same?

Thoughts, comments are welcomed.

[cowtowncoder]

Sounds reasonable that such characters (if and when allowed by YAML) should be properly escaped so that round-trip handling would work. So sounds like a bug.
I don't remember if there are relevant settings, off the top of my head, but I guess there aren't (you probably checked :) ).

[eginez]

Thanks for confirming @cowtowncoder. As far as I can tell this bug is in SnakeYAML? Would that be a fair assessment?

[cowtowncoder]

@eginez It does sound like it would be, but I have not had a chance to check this yet. If you can write a simple reproduction against SnakeYAML, that'd allow filing a bug against it.

@asomov would be a good contact here, I think.

[asomov]

@eginez what is swriter.toString() ?

[asomov]

@eginez @cowtowncoder I made a test and it is green:

  public void testKey() {
    String key = "SomeKey:\n\nOtherLine";
    Map<String, Integer> map = new HashMap<>();
    map.put(key, 302);
    Yaml yaml = new Yaml();
    String obj = yaml.dump(map);
    assertEquals("? |-\n"
        + "  SomeKey:\n"
        + "\n"
        + "  OtherLine\n"
        + ": 302\n", obj);
    Map<String, String> parsed = yaml.load(obj);
    assertEquals(302, parsed.get(key));
  }

[eginez]

@asomov interesting so the bug could indeed somewhere in the jackson library. We should expect this to work right??? (currently fails)

@Test
    public void testYaml2() throws Exception {
        String key = "SomeKey:\n\nOtherLine";
        Map<String, Integer> map = new HashMap<>();
        map.put(key, 302);

        Yaml yaml = new Yaml();
        String dump = yaml.dump(map);

        YAMLFactory yamlFactory = new YAMLFactory();
        ObjectMapper yamlObjectMapper = new ObjectMapper(yamlFactory);
        StringWriter swriter = new StringWriter();
        yamlObjectMapper.writeValue(swriter, map);

        Assert.assertEquals(dump, swriter.toString());
    }

The only difference is the absence of |-

@asomov swriter.toString() pushes the contents of the string buffer to a string object

[cowtowncoder]

It does sound like potential Jackson bug. I can probably use/repurpose the original sample; the goal is not so much to replicate what specific SnakeYAML settings produce but to ensure that what is written is read back reliably.

I suspect that Jackson's logic that tries to prevent coercion of "NO" into false is leading it to specify some output mode that disables SnakeYAML's escaping or checks.

[cowtowncoder]

I added a simple failing test like so:

    public void testComplexName() throws Exception
    {
        final String key = "SomeKey:\nOtherLine";
        Map<?,?> input = Collections.singletonMap(key, 302);
        final String doc = MAPPER.writeValueAsString(input);
        Map<?,?> actual = MAPPER.readValue(doc, Map.class);
        assertEquals(input, actual);
    }

and will try to see if I can figure out how to resolve this, since SnakeYAML should be able to handle it properly.

[eginez]

this is great thanks all!!

[asomov]

@cowtowncoder feel free to ping me if you need any help

[cowtowncoder]

@asomov Will do if need be, thanks!

Fix is in, for 2.13.2 release. Covers linefeed case but I suspect there may be other things that require quoting.