Fields with `default` not always set in the resource config during discover

[travjenkins]

I could see how this might not be a bug... but kind of feels like one to me and also causes an issue in the UI.

The source-postgres connector has a resource config schema that contains this property:

    "mode": {
      "type": "string",
      "enum": [
        "",
        "Normal",
        "Precise",
        "Only Changes",
        "Without Primary Key"
      ],
      "title": "Backfill Mode",
      "description": "How the preexisting contents of the table should be backfilled. This should generally not be changed.",
      "default": ""
    }

However during discover this default is not set on any of the bindings.

"bindings": [
      {
          "resource": {
              "namespace": "public",
              "stream": "bigtables00"
          },
          "target": "acme/foo/public/bigtables00"
      },
      {
          "resource": {
              "namespace": "public",
              "stream": "bigtables01"
          },
          "target": "acme/foo/public/bigtables01"
      },
      ...

This can cause problems in the UI as our schema validation tool ajv is setup to insert defaults when a property is not there. We could look into turning this off only for the edit flow - but I first wanted to gauge people's thoughts.

I think that having the empty string being a value is okay but marking it as the default seems unnecessary since the user could just leave that prop off all together.

[travjenkins]

We chatted in post stand up and since everyone agrees that this is not a huge issue and does not impact a lot of users we will not take any action on this.

The true intent for default in json schema is that it is stating the value that will be used if the prop is NOT in the config. This is not how the UI consumes this as it will use the default value and insert that value into the config if it is missing.

A true technically correct solution to this concern would be for the UI to have a good UI/UX to make it clear to a user that they can safely leave things blank and the connector will figure out the best value for them.

[travjenkins]

Marking as wontfix for not.