Too many quotes in generated command

[SteadyGiant]

I originally submitted this issue to dbt_external_tables. Perhaps it belongs in dbt-core instead.

Describe the bug

When I run dbt run-operation stage_external_sources, I get the error message:

Encountered an error while running operation: Database Error cross-database reference to database "sources" is not supported

because dbt tries running this command:

drop table if exists "sources"."src_pendo"."src_accounts" cascade

when it should be:

drop table if exists "sources.src_pendo.src_accounts" cascade

And, indeed, when I run the latter SQL command in Redshift Query Editor on my warehouse there's no error, whereas when I run the former SQL command I get the same error.

Steps to reproduce

I'm running all CLI commands in PowerShell.

My models/staging/pendo/src_pendo.yml file (following this example) looks like this (one column for brevity):

version: 2

sources:
  - name: s3_pendo
    database: sources
    schema: src_pendo
    loader: S3
    loaded_at_field: _sdc_batched_at
    tables:
      - name: src_accounts
        external:
          location: <s3 path>
          row_format: serde 'org.apache.hadoop.hive.serde2.OpenCSVSerde'
          table_properties: "('skip.header.line.count'='1')"
          stored_as: parquet
        columns:
          - name: account_id
            data_type: varchar
            tests:
              - not_null
              - unique

<s3 path> contains CSV files.

Expected results

If I'm understanding correctly, the dbt run-operation stage_external_sources macro will create the external schema and table defined in src_pendo.yml in Redshift Spectrum, then populate the table with all data in the CSV files in <s3 path>. Let me know if this isn't the use case.

Actual results

See bug description.

Screenshots and log output

Full (PowerShell) output after running the macro:

System information

The contents of your packages.yml file:

packages:
  - package: dbt-labs/dbt_external_tables
    version: 0.8.0

Which database are you using dbt with?

• redshift
• snowflake
• other (specify: ____________)

The output of dbt --version:

installed version: 1.0.1
   latest version: 1.0.1

Up to date!

Plugins:
  - postgres: 1.0.1
  - redshift: 1.0.0

The operating system you're using: Windows 10

The output of python --version: Python 3.9.6

Additional context

If this is truly a bug then I'll try submitting a PR.