[Bug]: Deleting a generated file doesn't show diagnostics immediately

[Dilhasha]

Description

Delete a generated file that has a function used by a non-generated function. That doesn't show diagnostics immediately without reloading. This is applicable for both source and test files.

Steps to Reproduce

For source files:

main.bal

import ballerina/io;

public function main() {
    io:println("Hello, World!");
    io:println(helloTest());
}

generated/main_new.bal

function helloTest() returns string {
    return "Hello World";
}

For test files:

mod1/test1.bal

@test:Config {}
function testFunction2() {
    string welcomeMsg = helloTest();
    test:assertEquals("Hello World", welcomeMsg);
}

generated/mod1/test_new1.bal

function helloTest() returns string {
    return "Hello World";
}

We need to test same for when using source function in a test case and deleting source file.

Affected Version(s)

2201.4.x, 2201.5.0

OS, DB, other environment details and versions

No response

Related area

-> Other Area

Related issue(s) (optional)

No response

Suggested label(s) (optional)

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Suggested assignee(s) (optional)

No response

[Dilhasha]

This happens only for the default module i.e. if a function in a generated file is called in another project file and then the generated file is deleted.

But calling non-default module functions from any module does not result in the mentioned behavior.

<style type="text/css"></style>

The function is defined at	The function is called at	immediately shows diagnostic when deleted
generated default module source	default module source	no
generated default module source	generated default module test source	no
generated default module source	default module test source	no
generated non-default module source	default module source	yes
generated non-default module source	non-default module source	yes
generated non default module source	generated default module source	yes
generated non default module source	generated non-default module test source	yes

The only difference I could notice between the two scenarios is that the params parameter has a duplicated entry during deleting the default module function in the below method call.

https://github.com/ballerina-platform/ballerina-lang/blob/master/language-server/modules/langserver-core/src/main/java/org/ballerinalang/langserver/BallerinaWorkspaceService.java#L87

[Dilhasha]

This was due to a duplicated listener registered for same file.