Incubator-superset: Malformed JSON in the extras field: SyntaxError: Unexpected end of JSON input

[gamebusterz]

While adding a new database connection (tried for Postgres and Redshift both), clicking on 'Test Connection' gives Malformed JSON in the extras field: SyntaxError: Unexpected end of JSON input error.
The Extra field has

{
    "metadata_params": {},
    "engine_params": {},
    "metadata_cache_timeout": {},
    "schemas_allowed_for_csv_upload": []
}

And the Secure Extra field is empty. I also tried removing the JSON in the Extra field altogether but I still get this error.

The connection strings, I've tried are:
redshift+psycopg2://user:pass@host/dbname for Redshift and postgresql://user:pass@host:5432/dbname for Postgres

Expected results

The connection should be tested successfully.

Actual results

Clicking on 'Test Connection' gives Malformed JSON in the extras field: SyntaxError: Unexpected end of JSON input error.

Screenshots

How to reproduce the bug

1. Go to Sources > Databases
2. Click on 'Add a new record' (Plus button)
3. Keeping all the field as it is, just add the database name and database URI
4. Click on 'Test Connection' to see the error.

Environment

(please complete the following information):

• superset version: "0.999.0dev",
• python version: Python 3.6.7
• node.js version: v13.1.0
• npm version: 6.12.1

Checklist

Make sure these boxes are checked before submitting your issue - thank you!

• [X] I have checked the superset logs for python stacktraces and included it here as text if there are any.
• [X] I have reproduced the issue with at least the latest released version of superset.
• [X] I have checked the issue tracker for the same issue and I haven't found one similar.

Additional context

I have copied the default JSON in the extras field and checked its validity, and it is a valid JSON.

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[dpgaspar]

Hi @gamebusterz,

Thank you for taking the time to report this, I'm able to reproduce

Investigating cause and possible fix

[maxmelnick]

@dpgaspar - I added #8630 to fix this issue.

Also, sorry...realize I missed this issue at first glance and created a new issue #8628 . I'll close my issue and update my PR to reference fixing this issue.

[bharath0208]

Getting the same error when trying to add a new presto database connection. It was working fine until last Tuesday. For some reason, I had to re-deploy my docker containers and then now I started seeing this error.

[gamebusterz]

@bharath0208 are you using the latest version?

[bharath0208]

@gamebusterz I think it's fixed now I tried with the latest version and I don't see the error anymore