[v2.0.0-x] Error: Failed to resolve repeated object (this should not happen)

[MikeRalphson]

Describe the bug

When stringifying an object containing multiple references to the same object which have been serialised as strings, the anchor mechanism seems to get confused.

To Reproduce

const yaml = require('yaml');

const o = {};

const d = new Date();

o.d1 = d;
o.d2 = d;

console.log(yaml.stringify(o));

/Users/mikeralphson/node/oad/node_modules/yaml/dist/doc/anchors.js:67
                    throw error;
                    ^

Error: Failed to resolve repeated object (this should not happen)
    at setAnchors (/Users/mikeralphson/node/oad/node_modules/yaml/dist/doc/anchors.js:64:35)
    at Document.createNode (/Users/mikeralphson/node/oad/node_modules/yaml/dist/doc/Document.js:110:9)
    at new Document (/Users/mikeralphson/node/oad/node_modules/yaml/dist/doc/Document.js:50:34)
    at Object.stringify (/Users/mikeralphson/node/oad/node_modules/yaml/dist/public-api.js:100:12)
    at Object.<anonymous> (/Users/mikeralphson/node/oad/bin/testyd.js:10:18)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12) {
  source: 2021-06-17T10:49:08.525Z,
  ref: { anchor: 'a1', node: null }
}

Expected behaviour

yaml.stringify should not throw an Error.

Versions (please complete the following information):

• Environment: Node.js 14.16.0
• yaml: 2.0.0-6

Additional context

yaml 1.x stringifies this as two strings without an anchor.

[eemeli]

Good catch! There was an early return when creating scalars that didn't take this into account. Should be fixed now.