[Bug]: RecordTypeSymbol.fieldDescriptors() returns NPE

[TharmiganK]

Description

I have an error intersection like this:

type ErrorDetail record {
    string|string[] headers?;
    anydata body?;
};
type StatusCodeError distinct error<ErrorDetail>;
type NotFoundError distinct StatusCodeError;

type UserErrorInfo record {|
    string timeStamp;
    string userId;
    string message;
|};

type UserErrorDetail record {|
    *ErrorDetail;
    UserErrorInfo body;
|};

type Error distinct error;

type UserNotFoundError Error & NotFoundError & error<UserErrorDetail>;

In the compiler plugin, I am accessing this UserNotFoundError type symbol and get the effective error type from the intersection. Then I get the type descriptor of the detail field which is a Ballerina Record Type in this case.

When I call fieldDescriptors() method on this Record Type I am getting a Null Pointer Error.

Please note that this a blocker to this feature which is expected to deliver with update 9:

• Aligning error mapping with spec generation for new HTTP error structure ballerina-library#5135

Steps to Reproduce

See the description above.

Java code:

TypeSymbol intersectionErrorType = ((TypeReferenceTypeSymbol) typeSymbol).typeDescriptor();
TypeSymbol effectiveErrorType = ((IntersectionTypeSymbol) intersectionErrorType).effectiveTypeDescriptor();
TypeSymbol detailRecordType = ((ErrorTypeSymbol) effectiveErrorType).detailTypeDescriptor();
((RecordTypeSymbol) detailRecordType).fieldDescriptors();

Note:
If I change the error intersection like this then it works:

type Error0 distinct error<UserErrorDetail>;

type UserNotFoundError0 Error0 & NotFoundError;

Affected Version(s)

Ballerina SwanLake Update 8 (2201.8.4)

OS, DB, other environment details and versions

No response

Related area

-> Compilation

Related issue(s) (optional)

No response

Suggested label(s) (optional)

No response

Suggested assignee(s) (optional)

No response

[prakanth97]

In the type resolver, UserNotFoundError is resolved properly, seems semantic api is not exposing it in BallerinaRecordTypeSymbol

[nipunayf]

The latest changes in the master appear to work properly for the above scenario, even using the semantic API.

[TharmiganK]

@nipunayf please note that the sample is updated. The previous one was not reproducing this issue

[nipunayf]

The problem can be reduced to the following example.

type ErrorDetail record {
    string msg;
};

type UserNotFoundError distinct error & error<ErrorDetail> & error<ErrorDetail> ;

The error Cannot invoke "io.ballerina.tools.diagnostics.Location.lineRange()" because "symbol.pos" is null is generated at

ballerina-lang/compiler/ballerina-lang/src/main/java/io/ballerina/compiler/api/impl/symbols/BallerinaSymbol.java

Line 65 in 12560f8

LineRange lineRange = symbol.pos.lineRange();

After the first intersection between distinct error & error<ErrorDetail>, it generates a resultant record type, and the position of the msg field symbol is null, and this is propagated to the final intersection.

[github-actions]

This issue is NOT closed with a proper Reason/ label. Make sure to add proper reason label before closing. Please add or leave a comment with the proper reason label now.

      - Reason/EngineeringMistake - The issue occurred due to a mistake made in the past.
      - Reason/Regression - The issue has introduced a regression.
      - Reason/MultipleComponentInteraction - Issue occured due to interactions in multiple components.
      - Reason/Complex - Issue occurred due to complex scenario.
      - Reason/Invalid - Issue is invalid.
      - Reason/Other - None of the above cases.