[Introspection] Crashes when default value contains line breaks

[ejoebstl]

I've observed the Prisma 2 introspection code crash when a default value is not a constant, but some expression, in my case also containing a new line.

Consider a column in postgres with the following default value:

'Concatenated'||E'\n';

Introspection crashes with:

Schema parsing

error: Unexpected token. Expected one of: 
  -->  schema.prisma:389
   | 
388 |   columnName    String               @default("(Concatenated || 
389 | )")
   | ^ Unexpected token.

[janpio]

Needs decision @sorenbs:

• Can we handle this?
• Do we want to handle this?
• How do we want to handle this?

[sorenbs]

DECISION: Initially we will not support newlines in default values. If introspection encounters a default value with newlines, it should not print it.

We do not need to explicitly handle this in the parser - it is acceptable that we give random parse errors.

[janpio]

Slight adaptation: Let's treat this as a light guardrail, and print a comment in the schema - but not send a warning to the CLI as it doesn't make a difference right now.

[sorenbs]

Just don't spend any time trying to print a multi-line, commented-out default value. No mess like this:

model User {
  name String //@default("who thi
//nks a name should
//
//have line breaks????!?")
}

[janpio]

lol no - just a comment that the default value is missing here because %explanation+link%

Suggestion:

/// The default value of this field was skipped as it is currently not supported by Prisma. 
/// This does not negatively influence your app, as the default is enforced by the database.
/// Learn more at https://pris.ly/d/foo

[janpio]

Default value is removed - but is currently not treated as guardrail yet (which is not super important, but would be nice to have).