banDropNotNull¶

Group destructive · Recommended · Migrations only · Since 0.1.0
Diagnostic lint/banDropNotNull

Sources: inspired by squawk/ban-drop-not-null

Description¶

Dropping a NOT NULL constraint may break existing clients.

Application code or code written in procedural languages like PL/SQL or PL/pgSQL may not expect NULL values for the column that was previously guaranteed to be NOT NULL and therefore may fail to process them correctly.

You can consider using a marker value that represents NULL. Alternatively, create a new table allowing NULL values, copy the data from the old table, and create a view that filters NULL values.

Examples¶

Invalid¶

alter table users alter column email drop not null;

code-block.sql:1:1 lint/banDropNotNull ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Dropping a NOT NULL constraint may break existing clients.

  > 1 │ alter table users alter column email drop not null;
      │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    2 │ 

  i Consider using a marker value that represents NULL. Alternatively, create a new table allowing NULL values, copy the data from the old table, and create a view that filters NULL values.

How to configure¶

{
  "linter": {
    "rules": {
      "banDropNotNull": "error"
    }
  }
}

How to suppress¶

Suppress this diagnostic with a comment:

-- pgls-ignore banDropNotNull