textDocument/publishDiagnostics called multiple times but only one of the file's diagnostics are shown

[rcjsuen]

vscode-languageserver-node/client/src/common/client.ts

Lines 1742 to 1747 in 8e6bf18

	private setDiagnostics(uri: Uri, diagnostics: VDiagnostic[] | undefined) {
	if (!this._diagnostics) {
	return;
	}
	this._diagnostics.set(uri, diagnostics);
	}

I have a language server that boots up and scans the workspace folders. It finds four files to scan and publishes diagnostics for all four of them and only one of them has diagnostics in the "Problems" pane.

I have confirmed with a breakpoint that this._diagnostics.set(uri, diagnostics); is called multiple times but only one of the file's diagnostics are being shown. If I try to debug further I am greeted with your standard unreadable extensionHostProcess.js.

The traces for the missing files seem correct and I even made the correct one have an incorrect URI and it still showed up in the "Problems" pane just fine. This is 100% reproducible so I'm not convinced it's some strange race condition...? 🤨 How can I debug the extension so that I can walk through actual VS Code source code instead of looking at the unreadable extensionHostProcess.js?

[dbaeumer]

@rcjsuen you would need to run and compile VS Code from source :-). The instructions are here: https://github.com/microsoft/vscode/wiki/How-to-Contribute

Have you tried to reproduce this with a simple VS Code extension that adds the diagnostics directly in code?

[rcjsuen]

you would need to run and compile VS Code from source :-)

Sounds painful. :)

Have you tried to reproduce this with a simple VS Code extension that adds the diagnostics directly in code?

Great suggestion. I tried that and couldn't reproduce it.

vscode-languageserver-node/client/src/common/client.ts

Lines 1694 to 1705 in 8e6bf18

	private handleDiagnostics(params: PublishDiagnosticsParams) {
	if (!this._diagnostics) {
	return;
	}
	const key = params.uri;
	if (this._diagnosticQueueState.state === 'busy' && this._diagnosticQueueState.document === key) {
	// Cancel the active run;
	this._diagnosticQueueState.tokenSource.cancel();
	}
	this._diagnosticQueue.set(params.uri, params.diagnostics);
	this.triggerDiagnosticQueue();
	}

Also cheated with client as any and then calling the private handleDiagnostics function and that seems to work. I'll try to examine the payloads more closely to make sure I didn't make any copy/paste errors and see if I can further refine my testing...

[rcjsuen]

@dbaeumer I figured out the problem. It seems like vscode.DiagnosticSeverity.Hint diagnostics is intended to not show up in "Problems"...? 🤷 I only see three of the four.

const collection = vscode.languages.createDiagnosticCollection("rcjsuen-testing");
collection.set(vscode.Uri.file("/rcjsuen/testing"), [
    new vscode.Diagnostic(new vscode.Range(0, 0, 0, 10), "Error", vscode.DiagnosticSeverity.Error),
    new vscode.Diagnostic(new vscode.Range(0, 0, 0, 10), "Hint", vscode.DiagnosticSeverity.Hint),
    new vscode.Diagnostic(new vscode.Range(0, 0, 0, 10), "Information", vscode.DiagnosticSeverity.Information),
    new vscode.Diagnostic(new vscode.Range(0, 0, 0, 10), "Warning", vscode.DiagnosticSeverity.Warning),
])

[rcjsuen]

Looks like this is intentional (microsoft/vscode#45436) and someone else reported this this year (microsoft/vscode#203569). 🤔