feature request: public the TransformationContext.addDiagnostic and read them in the compiler and transpileModule

Search Terms

custom transformer diagnostic

Suggestion

mark the method addDiagnostic in TransformationContext as public and read the diagnostic result in the compiler

Use Cases

I'm writing a custom transformer. In some cases, the transform will fail but I don't want to throw an Error. I want to add my error to the diagnostics.

Examples

I have tried to call the addDiagnostic by as any

function createDiagnosticForNodeInSourceFile(
    ts: ts,
    sourceFile: SourceFile,
    node: Node,
    message: DiagnosticMessage,
    arg0?: string | number,
    arg1?: string | number,
    arg2?: string | number,
    arg3?: string | number,
): DiagnosticWithLocation | undefined {
    return (ts as any).createDiagnosticForNodeInSourceFile?.(sourceFile, node, message, arg0, arg1, arg2, arg3)
}
function appendDiagnosticMessageForNode(context: TransformationContext, diag: DiagnosticWithLocation | undefined) {
    if (!diag) return false
    const _context = internalTransformationContext(context)
    if (!_context.addDiagnostic) return false
    _context.addDiagnostic(diag)
    return true

    function internalTransformationContext(
        context: TransformationContext,
    ): TransformationContext & { addDiagnostic?(diag: DiagnosticWithLocation): void } {
        return context as any
    }
}

But that doesn't work. After digging into the source code, I found that it seems like the diagnostics only read in the dts generating.

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

まず、issue で言及されている compiler、transpileModule、および宣言生成のパスを通じて TransformationContext.addDiagnostic を追跡します。現在 transformer の診断がどこで読み取られているかを確認し、カスタム transformer によって追加された診断が compiler と transpileModule の結果に到達することを示すために必要なテストを特定します。